www.geologicacarpathica.sk
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA
, FEBRUARY 2012, 63, 1, 33—48 doi: 10.2478/v10096-012-0003-9
Introduction
The Vâlcan Mountains are located in the Southern Car-
pathians between the Jiu Valley (to the east), the Petro ani Ba-
sin (to the north), the Motru Valley (to the west) and the Getic
Depression (to the south). The Upper Jurassic—Lower Creta-
ceous limestones crop out on the southern border of the Vâl-
can Mountains and they were studied in stratigraphic sections
along the Cheii, Pocuia, Sudoie ului, Valea lui Mare ,
Cire ului, Albului, Pârgavului, Bistri a, and Sârbului Valleys.
More than 800 samples have been collected and analysed.
In spite of the large number of previous regional geology
studies on this area, there are only a few data regarding the
biostratigraphy and lithology of the local sedimentary depos-
its. This is due to the scarcity of biostratigraphic markers
within these deposits and to their recrystallization caused by
late Senonian tectonics (Pop & Bucur 2001). This study repre-
sents a synthesis of the data obtained from a vast area in the
Vâlcan Mountains. It aims to describe the facies and microfa-
cies, to reconstruct the paleoenvironments and their evolution
in time, and to bring some new biostratigraphical data.
Geological setting
The structure of the western part of the Southern Car-
pathians is represented by three groups of tectonic units. The
lowermost unit is the Danubian Nappes, also called Danubi-
an Euxinides (Balintoni 1997), the Danubian Domain or
Danubian Autochthonous. This unit is overlain by the Sever-
in Nappe, representing the suture between the Danubian
An Upper Jurassic—Lower Cretaceous carbonate platform
from the Vâlcan Mountains (Southern Carpathians,
Romania): paleoenvironmental interpretation
MIHAI MICHETIUC
1
, CAMELIA CATINCU
1
and IOAN I. BUCUR
1,2
1
Babe -Bolyai University, Department of Geology, M. Kogălniceanu Str. 1, 400084 Cluj-Napoca, Romania;
m.michetiuc@yahoo.com; camelia0409@yahoo.com
2
Babe -Bolyai University, Centre for Integrated Geological Research, M. Kogălniceanu Str. 1, 400084 Cluj-Napoca, Romania;
ioan.bucur@ubbcluj.ro
(Manuscript received January 10, 2011; accepted in revised form June 9, 2011)
Abstract: The results of a biostratigraphic and sedimentological study of the Upper Jurassic—Lower Cretaceous limestones
cropping out in the southern sector of the Vâlcan Mountains in Romania are presented, including the definition of microfacies
types, fossil assemblages and environmental interpretation. Six microfacies types (MFT 1—MFT 6) have been identified,
each of them pointing to a specific depositional environment. The deposits are characteristic of a shallow carbonate platform.
They contain normal marine or restricted marine facies deposited in low or high energy environments from the inner, middle
and outer platform. The age attribution of these deposits (Late Jurassic to Berriasian—Valanginian—?Hauterivian, and Barremian)
is based on foraminiferal and calcareous algae associations. The micropaleontological assemblage is exceptionally rich in the
Vâlcan Mountains and brings new arguments for dating the Upper Jurassic—Lower Cretaceous limestones in this area.
Key words: Upper Jurassic—Lower Cretaceous, Vâlcan Mountains, paleoenvironment, carbonate platform, carbonate
sedimentology, microfacies.
Nappes and the Getic Nappe, which is the uppermost unit.
Except for some thin strips belonging to the Getic Nappe, the
Vâlcan Mountains are dominated by the crystalline and vol-
canic rocks of the Lower Danubian Nappes (Berza et al.
1983), and by their Mesozoic cover (Fig. 1). The Mesozoic
deposits belong to the sedimentary cover of the Lainici
Nappe (Berza in Balintoni et al. 1989).
The succession of the Mesozoic deposits in the area starts
with Liassic deposits in Gresten-type Facies, followed by
carbonate deposits of variable thickness (1—20 m), Middle
Jurassic in age. The Upper Jurassic is represented by three
formations: the Valea Pragurilor Formation (Oxfordian) – a
calcarenitic sequence, often consisting of dolosparites; the
Valea Cheii Formation (Upper Oxfordian—Lower Kimmerid-
gian) – a siliciclastic formation with regressive character
(1—20 m thick); and the Tope ti Formation (Kimmeridgian—
Tithonian) – consisting of shallow-water carbonate deposits
dominated by blackish, fine to coarse stratified calcarenites
and calcilutites. On the top of the Upper Jurassic deposits, a
40 m thick Neocomian limestone succession crops out. The
Izvarna Formation (Barremian—Aptian) is the last carbonate
formation developed in this region and it consists of Urgonian
limestones, followed transgressively, and sometimes uncon-
formably, by Upper Cretaceous clayey marls, marly-lime-
stones and clays (Pop 1973; Pop & Bucur 2001) (Fig. 2).
New biostratigraphic data
In a previously published study (Michetiuc et al. 2008) we
performed a micropaleontological study concerning only the
34
MICHETIUC, CATINCU and BUCUR
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA, 2012, 63, 1, 33—48
Lower Cretaceous deposits from several sections (Cheii,
Sudoie ului, Cire ului, Albului, Pârgavului) in the Vâlcan
Mountains. We combined here the micropaleontological data
published earlier with new ones, in order to provide a synthet-
ic image of the stratigraphic succession (Fig. 3). The studied
deposits can be assigned to the Upper Jurassic—Lower Creta-
ceous (Oxfordian—Barremian) with some uncertainties regard-
ing the Hauterivian deposits which were not documented
paleontologically due to a lack of reliable biostratigraphic
markers. Here we focus on our new findings which are dis-
cussed in order to stress their biostratigraphical significance.
The Late Jurassic age attribution is based on foraminifera:
Alveosepta jaccardi (Schrodt) (Fig. 4.1), Parurgonina caelin-
ensis Cuvillier, Foury & Pignatti Morano (Fig. 4.2), Kurnubia
palastiniensis Henson (Fig. 4.3), Protopeneroplis striata
Weyschenk (Fig. 4.4), Neokilianina sp., Verneuilina sp., and
on several dasycladalean algae: Megaporella boulangeri
Deloffre & Beun (Fig. 4.5), Clypeina sulcata (Alth) (Fig. 4.6),
and Salpingoporella annulata Carozzi.
Among the foraminifera, the most significant species is
Alveosepta jaccardi (Schrodt). It was first described by Schrodt
(1894, as Cyclammina jaccardi) from Upper Oxfordian—Mid-
dle Kimmeridgian deposits in Switzerland. It was subsequent-
ly reported from Upper Oxfordian—Lower Kimmeridgian
formations in France and in Romania (Pelissié & Peybern
è
s
1982; Cociuba 1997; Pop & Bucur 2001). Septfontaine (1981)
proposed an A. jaccardi Biozone, ranging from Middle
Oxfordian to Early Kimmeridgian. The species was also de-
scribed from Kimmmeridgian rocks in Turkey and Mexico
(Altiner 1991; Oma
ñ
a & Arreola 2008).
Parurgonina caelinensis Cuvillier, Foury & Pignattti Morano
was first described from Kimmeridgian—Portlandian forma-
Fig. 1. Location of the studied area (simplified map after Berza et al. 1994). 1 – Upper Danubian Nappes, 2 – Lower Danubian Nappes,
3 – Jurassic—Cretaceous cover, 4 – Getic Nappe, 5 – Severin Nappe, 6 – Pre-Alpine granitoids, 7 – Cenozoic basins, 8 – Fault, 9 – Over-
thrust. a—h – studied sections: a – Cheii, b – Pocuia, c – Sudoie ului, d – Valea lui Mare , e – Pârgavului, f – Albului, g – Cire ului,
h – Bistri a, i – Sârbului.
ñ
è
35
PALEOENVIRONMENTAL INTERPRETATION OF THE J/K CARBONATE PLATFORM (ROMANIA)
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA, 2012, 63, 1, 33—48
tions by Cuvillier et al. (1968). The species was placed either
in the Lower Kimmeridgian (Pelissié et al. 1984; Tasli
1993), the Kimmeridgian—Lower Tithonian (Pop & Bucur
2001; Bucur & Săsăran 2005; Velić 2007), or the Oxfordian—
Middle Tithonian (Bassoullet 1997a).
Kurnubia palastiniensis Henson is another typical fora-
minifer from Upper Jurassic deposits. It was found in Lower
Oxfordian (Pelissié & Peybern
è
s 1982), Oxfordian—Kim-
meridgian (Peybern
è
s 1976; Clark & Boudagher-Fadel
2002), Kimmeridgian (Hottinger 1967; Altiner 1991; Oma
ñ
a
& Arreola 2008), Kimmeridgian—Lower Tithonian (Pop &
Bucur 2001; Schlagintweit et al. 2005) or in Oxfordian—Mid-
dle Tithonian (Bassoullet 1997a; Bucur & Săsăran 2005;
Velić 2007) formations. To summarize, the distribution in-
terval for this species is Oxfordian—Middle Tithonian.
The same time interval is indicated by the calcareous algae
assemblage. Megaporella boulangeri Deloffre & Beun was
described from the Kimmeridgian of Morocco (Deloffre &
Beun 1986). Recently, Bouaouda et al. (2009) revised the
distribution of this alga in the Moroccan Atlantic basin; they
assigned it to the Callovian—Oxfordian interval. In the
Tethyan area, the species was identified by Pop & Bucur
(2001) in Kimmeridgian—Tithonian deposits from the South-
ern Carpathians, Romania. Clypeina sulcata (Alth) is typical
for the Kimmeridgian—Berriasian interval (Granier & Deloffre
1993; Bassoulet 1997b; Bucur 1999).
In the Berriasian—Valangian—?Hauterivian deposits, a mi-
cropaleontological association consisting of foraminifera:
Haplophragmoides joukowskyi (Charollais, Broennimann &
Zaninetti), Andersenolina cherchiae (Arnaud-Vanneau,
Boisseau & Darsac) (Fig. 4.7), Montsalevia salevensis
(Charollais, Broennimann & Zaninetti) (Fig. 4.8), Bramkam-
pella arabica Redmond, Vercorsella camposaurii (Sartoni &
Crescenti) (Fig. 4.9), Mohlerina basiliensis (Mohler), Mayn-
cina sp., and calcareous algae: Clypeina parasolkani Fari-
nacci & Radoičić, Clypeina sp., Salpingoporella circassa
(Farinacci & Radoičić), Salpingoporella annulata Carozzi,
and Macroporella praturloni Dragastan has been identified.
Andersenolina cherchiae (Arnaud-Vanneau, Boisseau &
Darsac) has been frequently reported from Berriasian—
Valanginian deposits (Arnaud-Vanneau 1980; Neagu 1994;
Bucur et al. 1995; Mancinelli & Coccia 1999; Pop & Bucur
2001). Velić (2007) considered H. joukowskyi, M. salevensis
and V. camposaurii to be index fossils for the Valanginian of
the Adriatic carbonate platform.
The Barremian—Aptian foraminiferal association consists
of the following species: Paracoskinolina? jourdanensis
(Foury & Moullade) (Fig. 4.10), Montseciella arabica (Hen-
son) (Fig. 4.11), Orbitolinopsis sp.?, Paracoskinolina sp.?,
Paracoskinolina cf. maynci (Chevalier) (Fig. 4.12), cf. Palaeo-
dictyoconus actinostoma Arnaud-Vanneau & Schroeder
(Fig. 4.13), ?Palorbitolina sp. (Fig. 4.14), Vercorsella scar-
sellai (De Castro) (Fig. 4.15), Everticyclammina hedbergi
(Maync), Pseudolituonella gavonensis (Foury), Debarina
hahounerensis (Fourcade, Roul & Vila), Neotrocholina
friburgensis Guillaume & Reichel, Sabaudia minuta (Hofker),
Pseudocyclammina lituus Yokoyama, Nautiloculina broenni-
manni Arnaud-Vanneau & Peybern
è
s, Everticyclamina sp.,
Vercorsella sp., Nautiloculina sp., Charentia sp. and Comma-
liama sp. The association of calcareous algae includes: Salpin-
goporella muehlbergii (Lorenz), Salpingoporella melite
Radoičić, Salpingoporella cf. cemi Radoičić, Salpingoporella
sp., Clypeina solkani Conrad & Radoičić, Clypeina cf. solkani
(Conrad & Radoičić), Suppiluliumaella tuberifera (Sokać &
Nikler), Milanovicella sp., Clypeina sp., Pseudoactinoporella
fragilis Conrad, Similiclypeina conradi Bucur, Salpingopo-
rella cf. genevensis (Conrad), Salpingoporella heraldica
Sokać, Salpingoporella urladanasi Conrad & Peybern
è
s, and
Falsolikanella danilovae (Radoičić).
As a whole, this association is characteristic of the Barremian
interval in the Mesogean area. Among the species in this asso-
ciation, the most important biostratigraphically are the orbito-
linids such as Paracoskinolina? jourdanensis (Foury &
Moullade). It represents clear paleontological evidence for the
Fig. 2. Stratigraphic succession of the Jurassic—Cretaceous deposits
from the Vâlcan Mountains (after Pop & Bucur 2001).
è
è
ñ
è
è
36
MICHETIUC, CATINCU and BUCUR
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA, 2012, 63, 1, 33—48
Fig. 3. General succession of the carbonate deposits from the Vâlcan Mountains, with vertical distribution of the identified marker micro-
fossils (composite section).
37
PALEOENVIRONMENTAL INTERPRETATION OF THE J/K CARBONATE PLATFORM (ROMANIA)
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA, 2012, 63, 1, 33—48
Fig. 4. 1—6 – Microfossils from the Upper Jurassic association. 1 – Alveosepta jaccardi (Schrodt) (Sample 9345A); 2 – Parurgonina
caelinensis Cuvillier, Foury & Pignatti Morano (Sample 9499); 3 – Kurnubia palastiniensis Henson (Sample 11); 4 – Protopeneroplis
striata Weyschenk (Sample 7); 5 – Megaporella boulangeri Deloffre & Beun (Sample 9502); 6 – Clypeina sulcata (Alth) (Sam-
ple 9502). 7—9 – Microfossils from the Berriasian—Valangian—?Hauterivian association. 7 – Andersenolina cherchiae (Arnaud-Vanneau,
Boisseau & Darsac) (Sample 208); 8 – Montsalevia salevensis (Charollais, Broennimann & Zaninetti) (Sample 45); 9 – Vercorsella cam-
posaurii (Sartoni & Crescenti) (Sample 253). 10—15 – Microfossils from the Barremian association. 10 – Paracoskinolina? jourdanensis
(Foury & Moullade) (Sample 9517); 11 – Montseciella arabica (Henson) (Sample 9577); 12 – Paracoskinolina cf. maynci (Chevalier)
(Sample 9600); 13 – cf. Palaeodyctioconus actinostoma Arnaud-Vanneau & Schroeder (Sample 262); 14 – Palorbitolina sp. (Sam-
ple 263); 15 – Vercorsella scarsellai (De Castro) (Sample 9571).
38
MICHETIUC, CATINCU and BUCUR
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA, 2012, 63, 1, 33—48
presence of Lower Barremian in the studied limestone succes-
sion (Michetiuc et al. 2008). The orbitolinids Paracoskinolina
cf. maynci (Chevalier) and cf. Palaeodictyoconus actinostoma
Arnaud-Vanneau & Schroeder, encountered in the upper part
of the succession from Sârbului Valley, have also been identi-
fied in the interval between the upper part of Lower Barremian
and the Lower Aptian (Masse 1976; Arnaud-Vanneau 1980;
Bucur 1997). Clavel et al. (2010) revised the biostratigraphic
distribution of the orbitolinids by correlation with ammonite
zonations placing the first occurrence of Paracoskinolina
maynci (Chevalier) in the Upper Hauterivian and that of the
Palaeodictyoconus actinostoma Arnaud-Vanneau & Schroeder
in the lowermost Barremian. The calcareous algae assemblage
characterizes the Barremian—Aptian time interval (Granier &
Deloffre 1993; Bucur 1999).
Microfacies analysis
We have identified six main microfacies types (MFT) with-
in these successions. Microfacies types (sensu Flügel 2004)
are defined according to criteria that allow attribution of spe-
cific environmental factors and specific depositional settings.
The microfacies criteria used here include: depositional tex-
ture and fabric, grain composition and early diagenetic fea-
tures. Each MFT and its occurrence is described and the
environmental interpretation is discussed.
MFT 1: non-fossiliferous, fenestral, laminated mudstone/
wackestone and subaerial exposure facies
This facies type is scarcely represented in the stratigraphic
succession, but is more frequent in the lower part. The most
typical diagnostic features are the presence of non-fossilifer-
ous (or poorly fossiliferous), unstructured or finely-laminated,
fine granular micrites, locally including cryptomicrobial
(Fig. 5.1,2) or Rivularia-type structures. Scattered dolomite
rhombs are locally present in the micritic matrix and grains.
Sometimes the original structure is obliterated by mosaics of
euhedral to subhedral dolomite crystals. Biodiversity is very
low, microfossils being mainly represented by ostracods,
rare foraminifera and gastropods (Fig. 5.3). Charophyte frag-
ments (stems and gyrogonites) are also locally present in a
homogeneous or fenestral matrix (Fig. 5.4). Some reworked
bioclasts from the subtidal area may also occur.
Also included in this facies association are sediments that
have undergone subaerial exposure. Exposure features in-
clude desiccation cracks, paleosols and paleokarst. They are
more common in the lower parts of the profiles from the
Sârbului and Bistri a Valleys.
Interpretation: Non-fossiliferous, finely laminated carbon-
ate muds and cryptalgal fabrics are common constituents of
supratidal or upper intertidal environments with low water
energy. In these areas the fluctuating salinity and frequent
subaerial exposures do not permit proliferation of infauna or
browsing organisms that homogenize the primary sedimen-
tary structures (Shinn 1983). The presence of charophyte re-
mains is usually regarded as good indicator of freshwater
environments (Tucker & Wright 1990), but salinity-tolerant
forms were also reported from recent and ancient brackish
environments (e.g. Burne et al. 1980; Feist & Grambast-
Fessard 1984; Climent-Dom
è
nech & Martín-Closas 2009).
In the studied area the charophyte remains appear along with
a brackish fauna of ostracods, and some are impregnated
with Fe-oxides. The preferential staining of bioclasts is proba-
bly similar to the preferential blackening of Pleistocene corals
in Florida, attributed by Strasser (1984) to the percolation of
staining fluids through their skeletons. The red pigmentation
is probably related to subaerial alteration (Wright et al. 2000;
MacNeill & Jones 2006).
Evidence of pedogenic influence such as desiccation-brec-
ciation, mottling, glaebule development, black pebbles, root
structures and microkarst (Esteban & Klappa 1983; James &
Choquette 1984; Demicco & Hardie 1994), are all common
features of this facies association.
The in situ brecciation of muds has led to the formation of
polygonal fracture networks filled with sparite or with sedi-
ment containing peloids and pisoids (Fig. 5.5). Brecciation
can be induced by desiccation (Fig. 5.6), displacive crystalli-
zation of calcite, root activity and/or dissolution (Flügel
2004). Carbonate nodules (or glaebules in soil terminology,
see Esteban & Klappa 1983) are also frequent constituents of
caliche profiles, but their origins are not fully understood
(Wright & Tucker 1991). Circum-granular cracks, filled with
spar cement, usually develop around glaebules (Fig. 5.7).
They are formed by alternate shrinkage and expansion in-
duced by seasonal drying/wetting cycles (Esteban & Klappa
1983). Mottling from red-brown, yellow to grey is also
present (Fig. 5.8). This pedogenetic process may develop as
a result of fluctuating Eh—pH conditions or through redistri-
bution of iron oxide and iron hydroxide particles (Buurman
1980). The presence of black pebbles ‘floating’ in this type
of matrix is probably related to the burning of organic matter
because features like the gradation of blackening and the an-
gular nature of the pebbles (Fig. 5.9), seen here, are argu-
ments cited by Shinn & Lidz (1988) as characteristic of
subaerial blackening by fire. Other interpretations include
impregnation by dissolved, colloidal or finely particulate or-
ganic matter (Strasser 1984) or the blackening by finely dis-
seminated pyrite (Wright 1986a).
No rhizocretions have been encountered but some alveolar-
septal structures were found (Fig. 5.10). Similar structures
have been reported from ancient and recent paleosols (Adams
1980; Klappa 1980; Wright 1986b; Wright et al. 1988). They
have been interpreted by Wright (1986b) as resulting from
fungal activity around roots. Root traces represented by
rounded or irregular voids lined with dense micritic coatings
(Fig. 5.11) are interpreted as being the products of void lining
biofilms or calcitic cutans (MacNeil & Jones 2006).
Microkarstic products represented by collapse breccias,
solution voids, and some speleotems (flowstone) (Fig. 5.12)
are also present. Such structures probably represent the up-
per vadose zone (Esteban & Klappa 1983).
MFT 2: fenestral wackestone/packstone-grainstone
This MFT is interlayered at different levels within the whole
stratigraphic succession and is characteristic for the intertidal
è
39
PALEOENVIRONMENTAL INTERPRETATION OF THE J/K CARBONATE PLATFORM (ROMANIA)
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA, 2012, 63, 1, 33—48
Fig. 5. Deposits from the supratidal zone (MFT 1). 1 – microbial mats displaying crinkled lamination (Sample 220, Barremian); 2 – cryp-
tomicrobial structures (Sample 9408, Upper Jurassic); 3 – mudstone with ostracods (Sample 9345, Upper Jurassic); 4 – mudstone with
charophyte stems and gyrogonites (Sample 96, Barremian); 5 – brecciated micrite; fissures are filled with peloids and pisoids (Sam-
ple 234, Upper Jurassic); 6 – desiccation structures (mud chips) (Sample 9356, Upper Jurassic); 7 – incipient stage of glaebule develop-
ment; glaebules are surrounded by complete or incomplete circumgranular cracks (Sample 244, Upper Jurassic); 8 – paleosoil
development with intensive brecciation and mottling (Sample 236, Upper Jurassic); 9 – subangular black pebble displaying gradation of
blackening (Sample 242, Upper Jurassic); 10 – alveolar-septal structures (Sample 9344, Upper Jurassic); 11 – root traces lined with
dense micritic coatings (Sample 249, Upper Jurassic); 12 – flowstone structures (Sample 202, Upper Jurassic).
40
MICHETIUC, CATINCU and BUCUR
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA, 2012, 63, 1, 33—48
environment. One of the main features of these deposits is the
presence of fenestral structures. The fenestrae are a few milli-
meters in size and their shapes are flat to spherical or irregular.
They contain sparitic cement, geopetal infillings, or are filled
with vadose silt, pointing to a meteoric water influence. A
Fig. 6. 1—8 – Deposits from the intertidal zone (MFT 2). 1 – alternating deposition and erosion (arrow) processes, as a result of changes in
current velocity: quiet water deposition (bottom of the picture) vs. higher energy deposition (top of the picture) (Sample 213, Neocomian);
2 – peloidal wackestone with irregular fenestrae (Sample 217, Neocomian); 3 – laminoid-fenestral peloidal wackestone (Sample 9391, Up-
per Jurassic); 4 – microbial mats with small gastropods (Sample 216, Neocomian); 5 – burrowed micrite containing Favreina-type coproli-
tes grading into fenestral microbial mats (upper part) (Sample 9363, Upper Jurassic); 6 – intraclastic peloidal packstone-grainstone; note the
early cementation by micritic cements and bimodal sorting (Sample 9513, Neocomian); 7 – peloidal intraclastic grainstone with keystone
vugs (KV) (Sample 9465, Barremian); 8 – intraclastic peloidal packstone-grainstone with Rivularia-type microbial structure (arrow) (Sam-
ple 41, Neocomian). 9—11 – Deposits of the high-energy subtidal zone (MFT 3). 9 – very well-sorted peloidal bioclastic grainstone (Sam-
ple 7, Upper Jurassic); 10 – laminated peloidal grainstone (Sample 9396, Upper Jurassic); 11 – packstone-grainstone with large benthic
foraminifera (Pseudocyclammina lituus) (Sample 9515, Barremian).
transition from muddy low-energy deposits to grainy high-en-
ergy deposits was encountered in some of the cases. The limit
between them is usually marked by an erosional surface
(Fig. 6.1). Two subtypes have been distinguished on the basis
of structural and textural features: a) fenestral-laminated peloi-
41
PALEOENVIRONMENTAL INTERPRETATION OF THE J/K CARBONATE PLATFORM (ROMANIA)
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA, 2012, 63, 1, 33—48
dal wackestone (formed in low-energy hydrodynamic condi-
tions) and b) fenestral peloidal packstone-grainstone (formed
when the hydrodynamic energy was intermittently high).
MFT 2a
The first subtype (Fig. 6.2,3) is commonly associated
with microbial bindstones and wackestones. The biodi-
versity is still low; sometimes inside the fenestrae one can
find charophyte oogones, probably reworked. Gyrogo-
nites are easily transported, especially if they are desiccat-
ed (Wright 1990). Small gastropods are locally present in
the microbial mats (Fig. 6.4). Sometimes intensely biotur-
bated micrites, containing many Favreina-type coprolites
and rare ostracods, are grading into fenestral microbial
mats (Fig. 6.5). The fenestrae associated with this subfa-
cies are of laminoid-fenestral and irregular type.
MFT 2b
These deposits are moderately to well sorted, some-
times displaying bimodal sorting; the particles are repre-
sented by well-sorted and well-rounded peloids, micritic
intraclasts and oncoids. Bioclasts are relatively rare, they
are represented by foraminifera (miliolids, textulariids,
Sabaudia minuta (Hofker), Vercorsella sp.) sometimes
showing a micritic envelope, bivalves, gastropod molds,
algae, or Rivularia-type structures (Fig. 6.6—8). The
fenestral pores within these deposits are of spherical to ir-
regular types, and keystone vugs are also locally present.
Interpretation: As many authors mentioned (e.g. Tucker &
Wright 1990; Flügel 2004) the assignment of ancient lime-
stones to the intertidal environment is a difficult task. This is
due to the lack of reliable diagnostic features, and to the sim-
ilarities with the adjacent supratidal environments. Fenestral
structures in ancient and recent carbonate deposits are usual-
ly regarded as good indicators of upper intertidal to supratid-
al settings (Shinn 1983; Tucker & Wright 1990). Shinn &
Robbin (1983) showed that open fenestrae are destroyed by
mechanical compaction so that the preservation of fenestrae
of all types in mudstones signifies that the host sediments
were cemented before even shallow burial. Such an early ce-
mentation is a characteristic feature of peritidal deposits
(Grover & Read 1978; Shinn 1983; James & Choquette
1984; Tucker & Wright 1990). Fenestrae have polygenic ori-
gins and may be caused by wetting and drying of carbonate
mud, by degassing of decaying organic material, by drying
out of the surface of cyanobacterial mats (in case of laminoid
and irregular fenestrae), or by air and gas bubbles trapped
during deposition of the host sediment or generated by post-
depositional decay of organic matter (in the case of spherical
fenestrae) (Demicco & Hardie 1994). Keystone vugs present
in the grain-supported facies are probably the result of air-
bubble trapping during storm deposition in the swash zone
on beaches or in the sheetwash zone on tidal flats (Shinn
1986; Demicco & Hardie 1994; Flügel 2004). Irregular
fenestrae associated with cyanobacterial mats can be the re-
sult of irregular growth of these mats (Săsăran 2006).
Other characteristic features of the intertidal regime are ero-
sion alternating with deposition, as well as rapid changes in
current and wave velocity (Ginsburg 1975).
Fenestral limestones containing abundant fenestrae, associ-
ated with distinctive early diagenetic features (crystal silt,
leached fossils, micritization of bioclasts originating from nor-
mal marine environments), erosional surfaces, cryptalgal sedi-
ments, and a restricted fauna (ostracods and gastropods)
suggesting periodic emergence and desiccation, point to an in-
tertidal environment of formation in the case of these deposits.
MFT 3: peloidal bioclastic packstone/grainstone
These limestone types are interlayered at several levels
within the stratigraphic succession. The granular facies mainly
consists of moderate- to well-sorted peloids with subangular
to rounded morphologies (Figs. 6.9,10), besides rare superfi-
cial ooids, micritic intraclasts and oncoids. Micritized bio-
clasts are common. Skeletal grains appear in various
quantities and are represented by gastropods, fragments of bi-
valves and echinoderms, benthic foraminifera (Fig. 6.11), and
dasycladalean algae. The foraminifera include: Kurnubia pa-
lastiniensis Henson, Protopeneroplis striata Weyschenk,
Andersenolina cherchiae (Arnaud-Vanneau & Boisseau),
Mohlerina basiliensis (Mohler), Paracoskinolina? jourdanen-
sis (Foury & Moullade), Pseudocyclammina lituus Yokoya-
ma, Sabaudia minuta (Hofker), Vercorsella sp. The
dasycladalean algae are represented by Clypeina parasolkani
Farinacci & Radoičić, Pseudoactinoporella fragilis Conrad,
Salpingoporella sp. Also microbial nodules (of Rivularia-
type) occur.
Interpretation: The non-skeletal components, such as pe-
loids, intraclasts, ooids, cortoids and oncoids, and mostly
sparitic, or at least partly sparitic groundmass indicate an agi-
tated subtidal environment. The diverse skeletal components,
such as larger and smaller benthic foraminifera and calcareous
algae point to normal-marine, well-oxygenated conditions.
These deposits were formed in shallow subtidal environments
above the fair-weather wave base.
MFT 4: packstone-grainstone with rudists and wackestone/
packstone with green algae and foraminifera
These deposits, characteristic of the middle and upper part
of the section, consist of wackestone/packstone, and pack-
stone-grainstone with highly diversified paleontological as-
semblages: molluscs, benthic foraminifera, and green algae.
At certain intervals, rudists took part to the colonization of the
substrate building-up a typical Urgonian-type facies (Masse
1979, 1995; Gili et al. 1995) (Fig. 7.1,2). The rudists charac-
terizing this facies have a patchy distribution, thick shells,
large sizes, and they show no signs of perforation, micritiza-
tion or encrustation. The sediment associated with this facies
is usually represented by poorly washed packstone-grainstone
with small and very diverse foraminifera (especially miliolids,
cuneolinids and textulariids) and peloids (Fig. 7.3).
Another microfacies, associated with the rudistid one, is
represented by wackestone-packstone with green algae and
large benthic foraminifera (Fig. 7.4,5). The main characteristic
42
MICHETIUC, CATINCU and BUCUR
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA, 2012, 63, 1, 33—48
Fig. 7. 1—6 – Deposits from the shallow subtidal environments (MFT 4): 1—2 – poorly washed packstone-grainstone with large rudists and
small foraminifera (Samples 53 and 9488, Barremian); 3 – packstone-grainstone with abundant small foraminifera (Sample 9467, Barremian);
4 – bioturbated wackestone with abundant dasycladalean algae fragments (Sample 207, Neocomian); 5 – wackestone with orbitolinids
(Montseciella arabica) (Sample 95, Barremian); 6 – normal-marine deposits affected by subaerial exposure, leading to dissolution and vadose
silt infiltration (Sample 9486, Barremian). 7—12 – Deposits from the restricted subtidal environments (MFT 5). 7 – inhomogeneous wacke-
stone-packstone with Lithocodium (Sample 9498A, Barremian); 8 – Bacinella bindstone containing rudist fragments (Sample 98, Barremian);
9 – packstone with Bacinella oncoids (Sample 9460, Barremian); 10 – bored and micritized rudist fragment, encrusted by Bacinella and Li-
thocodium (Sample 79, Barremian); 11 – rudist fragment consumed by microbes; note the microstalactitic microbial cement formed beneath it
(probably also of microbial origin as suggested by their micropeloidal structure) (Sample 218, Barremian); 12 – pervasive dissolution of rudist
fragment and matrix and subsequent deposition of vadose silt (Sample 9472, Barremian). 13—15 – Deposits from the offshore zone (MFT 6).
13—14 – well sorted bioclastic grainstone with echinoderm plates and other recrystallized or micritized bioclastic fragments (Samples 101 and
9492, Barremian); 15 – packstone with angular bioclastic fragments; the large bioclastic fragment is a brachiopod shell (Sample 9538, Barremian).
43
PALEOENVIRONMENTAL INTERPRETATION OF THE J/K CARBONATE PLATFORM (ROMANIA)
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA, 2012, 63, 1, 33—48
of this microfacies is the diversification of organisms in mud-
supported, sometimes bioturbated matrix. Dasycladalean al-
gae are very frequent (Clypeina solkani Conrad & Radoičić,
Salpingoporella melite Radoičić, Salpingoporella muehl-
bergii (Lorenz), Similiclypeina conradi Bucur), along with
benthic foraminifera (Montseciella arabica (Henson), Neotro-
cholina friburgensis Guillaume & Reichel, Vercorsella
scarsellai (De Castro)) and other skeletal grains similar to
those of the high-energy environment (MFT 3).
Interpretation: The Lower Cretaceous rudists are usually re-
garded as characteristic inhabitants of very shallow waters and
are especially linked to the inner, more or less protected parts
of the Urgonian platforms (Masse 1976, 1979, 1992; Masse &
Philip 1981; Skelton & Gili 1991). Their association with a
grainy-muddy substrate containing abundant small foramini-
fera also suggests inner platform (lagoonal) conditions with
moderate to low-energy conditions.
The intensely bioturbated bioclastic wackestone microfacies
types containing normal marine fauna dominated by dasycla-
dalean algae besides foraminifera with complex tests, rudist
fragments, and gastropods have been interpreted as being
formed in the lower subtidal environment with low hydrody-
namic energy. The presence of dasycladalean algae points to
warm, relatively shallow waters (Bucur & Săsăran 2005).
Some of the beds containing microfacies types 3 and 4
show traces of subaerial exposure, such as dissolution and
recrystallization of bioclasts, or voids filled with vadose-silt
(Fig. 7.6).
MFT 5: wackestone/packstone with rudist fragments and mi-
croencrusters, and packstone-grainstone with microbialite
This MFT is associated with the subtidal marine facies pre-
sented above and it is represented by peloidal wackestone/
packstone with abundant microencrusters and bioclastic pack-
stone-grainstone with microbialite. The diversity of flora and
fauna is low, bioclasts being mainly represented by problem-
atic microencrusters of Bacinella- (very abundant) or Lithoco-
dium-type and Rivularia-type organisms (Fig. 7.7). Bacinella
is present either in the matrix of these deposits, or inside and
around the bioclastic fragments forming oncoids (Fig. 7.8,9).
The bioclastic fragments are mainly represented by bored and
micritized rudist fragments (Fig. 7.10) but never by whole
rudist shells. The sediment is inhomogeneous, suggesting in-
tensive burrowing.
Some of these deposits may contain a normal-marine fauna
with foraminifera, green algae, echinoids or rudists, associated
with peloids and intraclasts. This association witnesses an
original normal-marine environment later grading into a re-
strictive one, a change leading to the colonization of the sub-
strate by calcimicrobial structures (Fig. 7.11) and finally even
to the subaerial exposure of the sediment, with related dissolu-
tion, reprecipitation and micritization processes affecting the
bioclasts (Fig. 7.12).
Interpretation: This association is characterized by the pres-
ence of Bacinella and Lithocodium along with fragmented
rudist shells. The systematic position of Bacinella and
Lithocodium was intensely disputed; the first one being usual-
ly interpreted as a cyanobacterium (Schäffer & Senowbari-
Daryan 1983; Maurin et al. 1985; Camoin & Maurin 1988)
while the second one was regarded as a Codiacean alga, lituolid
foraminifer, or cyanobacterium (for a comparison of different
taxonomic interpretations see Schlagintweit et al. 2010). Re-
cently, Schlagintweit et al. (2010) re-interpreted these organ-
isms as being ulvophycean green algae.
Regardless of their taxonomic position, most authors regard
the two microproblematic organisms as being characteristic of
very shallow, well-oxygenated and relatively oligotrophic en-
vironments (Leinfelder et al. 1993; Dupraz & Strasser 1999,
2002; Pittet et al. 2002; Reolid et al. 2009). The large oncoids
with lobate outlines, dominated by microencrusters (Bacinella
and Lithocodium), correspond to oncoids of types 3 and 4 de-
scribed by Védrine et al. (2007) or to the organism-bearing
oncoids of Dahanayake (1977). The above-mentioned authors
ascribed these types of oncoids to the low-energy open-la-
goonal environments, where the microbial meshwork had
time to grow. In contrast, the smaller, spherical oncoids, with
micritic, homogeneous cortex (type 1 oncoids of Védrine et al.
2007) are often associated with packstone-grainstone and rep-
resent higher energy conditions.
Encrustation, borings, breakage, burrowing and micritiza-
tion are common, indicating low accumulation rates (Enos
1983). Oncoid growth also requires low sedimentary rates
(Peryt 1981; Flügel 2004; Védrine et al. 2007). The presence
of abundant oncoids in the Oxfordian of the Swiss Jura was
correlated (Védrine et al. 2007) with the beginning of a long-
term sea-level rise. Furthermore, the authors correlated the
different types of oncoids with small-scale sea-level fluctua-
tions. Consequently, this facies was probably formed in a
subtidal lagoonal environment characterized by reduced accu-
mulation rates and was mainly controlled by water depth.
MFT 6: bioclastic packstone/ grainstone
This facies dominates the upper part of the succession. The
most typical carbonate particles included are bioclasts, repre-
sented by echinoid plates (sometimes comprising more than
50 % of the total) of arenitic sizes and recrystallized fragments
of molluscs (Fig. 7.13). Most bioclasts either exhibit construc-
tive micritic envelopes, or are marginally or completely micri-
tized (Fig. 7.14). Besides, well-rounded to subangular peloids,
micritic intraclasts, microbial nodules, bryozoans, brachio-
pods, foraminifera (Montseciella arabica (Henson), Palorbi-
tolina sp., Palaeodyctioconus actinostoma Arnaud-Vanneau
& Schroeder), and dasycladalean algae are present. The echi-
noid fragments are well-rounded and locally show syntaxial
overgrowth cement. Some bioclasts are affected by processes
of micritization, dissolution and recrystallization under the ef-
fect of meteoric waters.
Interpretation: These deposits showing evidence of intense
reworking and containing a predominantly open marine fau-
na imply a formation in a marine environment with high hy-
drodynamic energy; they represent bioclastic shoals on the
platform margin or on highs in the platform interior (corre-
sponding to FZ 6 sensu Wilson 1975 and Flügel 2004). This
microfacies is sometimes associated with wackestones and
packstones containing angular bioclastic fragments and repre-
senting the perishoal offshore environment (Fig. 7.15).
44
MICHETIUC, CATINCU and BUCUR
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA, 2012, 63, 1, 33—48
Paleoenvironmental reconstruction and evolution
The detailed microfacies study allows the differentiation of
several facies belts. In a transect from the shoreline to the plat-
form margin the following facies zones occur: (1) inner plat-
form, (2) middle platform and (3) outer platform (Fig. 8). For
a better understanding of the depositional facies belts, com-
parisons with modern settings have been used.
1. Inner platform. In most of the studied sections the periti-
dal deposits dominate their lower parts, although some thin in-
tercalations exist in the whole section. The supratidal facies
belt was dominated by fine, non-fossiliferous muds (MFT 1)
representing the result of sedimentation on the vast, protected
supratidal marshes that were subject to periodic flooding by
sea water during spring tides and storm events. The charo-
phyte remains in some of these supratidal deposits suggests
the presence of freshwater ponds.
No well-developed caliche profile or karstic features have
been encountered in these deposits, but some evidence of sub-
aerial exposure and pedogenesis do exist. In contrast, the su-
pratidal deposits from the lower part of Sârbului section show
greater thickness, no marine influence and more pronounced
pedogenic features. Such deposits were defined by MacNeil &
Jones (2006) as “disconnected palustrine deposits”. Their lo-
cal presence suggests lateral facies variability, probably
caused by the inherited paleotopography or by differential
subsidence. A modern example of such deposits are the Flori-
da Everglades showing that the climate and topography were
important controls of the marginal marine settings (e.g. Platt
& Wright 1992).
The supratidal environments are good indicators of climat-
ic conditions: even without having any clay-mineralogical
data, but by virtue of sedimentological and early diagenetic
data (lack of evaporites, paleosoil characteristics, meteoric
water input) humid to sub-humid climatic conditions can be
assumed, similar to those of the modern Andros Island
(Ginsburg & Hardie 1975).
As already mentioned, recognition of the intertidal facies
belt and its subenvironments in ancient carbonates is a diffi-
cult task. Based on the energy of the environment we distin-
Fig. 8. Schematic reconstruction of the distribution of paleoenvironments of the Vâlcan car-
bonate platform.
guished a low-energy and a high-energy sub-environment.
The first one contains cryptalgal fabrics associated with lam-
inar-fenestral or irregular fenestral fabrics (MFT 2a). They
contain a restricted fauna and were deposited on intertidal
flats with shallow ponds. In recent intertidal environments,
situated especially in more humid climates, ponds are a very
common feature (Pratt et al. 1992). The presence of abun-
dant crustacean coprolites and burrows and their association
with microbialites are also indicative for intertidal environ-
ments. In recent environments, burrows by fiddler crabs are
abundant in the lower intertidal flats and subtidal ponds
(Shinn 1983, 1986).
The granular subfacies (MFT 2b) contains light grey intrac-
lasts and rounded peloids, suggesting reworking of an early
lithified sediment from the tidal flats. Some of them may rep-
resent high-energy events affecting the flats, while those con-
taining keystone vugs might represent poorly developed beach
ridges generated seaward of the tidal flats in the zone of break-
ing waves. Bimodal sorting is also a characteristic of beach
foreshores or beach storm layers (Taira & Scholle 1979).
In the studied sections, the peritidal deposits could not be
individualized into cycles with clearly visible deepening-
shallowing facies trends. This can be explained by lateral
migration of tidal flat subenvironments (facies mosaic;
Wilkinson & Drummond 2004; Wright & Burgess 2005).
2. Middle platform. The winnowed packstones and grain-
stones (MFT 3) rich in peloids, cortoids and intraclasts, con-
taining different amounts of reworked benthic foraminifera
and green algae, reflect deposition under high-energy condi-
tions. Moderate turbulence is indicated by high packing densi-
ty, good sorting and roundness of particles (Bauer et al. 2002).
They represent subtidal sand bars moved by bottom currents.
In some cases, especially in the lower parts of the sections,
where they are associated with intertidal deposits, they might
represent tidal channel infillings. Unfortunately, the presence
of tidal channels can only be assumed because bipolar (her-
ringbone) cross-stratification is not present, possibly having
been destroyed by intense bioturbation.
The low-energy subtidal environments (MFT 4) dominate
the middle—upper parts of the sections and were deposited in
protected or semi-protected parts of the
platform. The protection was ensured
by the bioclastic shoals on the platform
margin (see discussion below). The
ecological requirements of fauna and
flora (especially benthic foraminifera
and green algae) suggest a shallow-
marine environment. The same envi-
ronment is inferred for the rudists
assemblages, which were compared
(Masse 1976; Masse et al. 2003) with
the Pinna—Pinctada assemblages thriv-
ing in the shallow-waters of Shark Bay
or the Arabian Gulf. Such shallow-wa-
ter environments were very sensitive to
bathymetric changes that could either
open or isolate the carbonate platform.
These middle platform deposits show
meter-scale cycles, each displaying a
45
PALEOENVIRONMENTAL INTERPRETATION OF THE J/K CARBONATE PLATFORM (ROMANIA)
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA, 2012, 63, 1, 33—48
shallowing-upward trend. At one end of the spectrum are the
mud dominated algal, foraminiferal wackestone—packstones,
representing the deeper, protected environments of the photic
zone. They are followed by packstones—grainstones with
small foraminifera, associated with rudists, representing shal-
lower and more energetic environments. The lack of micritiza-
tion, borings and encrustation on rudists shells suggests high
depositional rates. In the middle part of the sections (Lower
Barremian) the cycles are predominantly composed of rudist
fragments and microencrusters (MFT 5). They also show a
shallowing-up trend from deeper, low-energy environments,
to shallower and more energetic environments. The presence
of oncoids, intensive burrowing, perforations and micritiza-
tion suggest lower sedimentary rates. The fragmentation of
rudists is probably the result of intensive in-situ bioerosion
(Gili 1992; Gili et al. 1995) or of periodic reworking by high-
energy episodes.
Sometimes the cycles are capped by thin fenestral wacke-
stones and mudstones of the intertidal zone. The superim-
posed meteoric diagenesis (grain dissolution, recrystallization,
vadose silt) especially affected the MFT 5 and to some extent
the MFT 4, suggesting frequent subaerial exposures.
Such shallowing-up sequences in peritidal settings can
form through allocyclic or autocyclic processes (Strasser
1991). Autocyclic processes can be created by progradation
or migration of sedimentary systems (e.g. Ginsburg 1971;
Pratt & James 1986; Strasser 1991) without being related to
a sea-level fall. Allocyclic control mechanisms are indepen-
dent of the depositional processes and are commonly related
to different orders of eustatic sea-level fluctuations (e.g. Vail
et al. 1991; McLean & Mountjoy 1994; Strasser et al. 1999).
In our case, because of the bad outcrop conditions and the
effects of late Senonian tectonics, a correlation of meter-
scale cycles between sections is not possible, making it dif-
ficult to determine which of the two mechanisms (or a
combination of both) was involved. Still, in some of these
cycles vadose diagenesis directly overprints the subtidal fa-
cies, suggesting that allocyclic processes played an impor-
tant role in the formation of these sequences (Strasser 1991;
Strasser & Hillgärtner 1998; Burgess 2006).
3. Outer platform. The great thickness of the deposits,
predominance of echinoderm fragments along with other
stenohaline organisms, and the early diagenetic features sug-
gest the existence of bioclastic shoals situated at the platform
margin. These shoals were probably the main cause of plat-
form restriction, separating the inner and middle platform
from the open ocean (Fig. 8). The closest recent counterpart
is represented by the bank-margin shoals of the Great Bahama
Bank (Rankey & Reeder 2011). Even though this facies was
encountered only in the Upper Barremian, the existence of a
high-energy barrier at the platform margin before this period
can be inferred from the prevailing restricted conditions.
Likewise, in a section situated westward of the studied zone
(Mehedin i Plateau), belonging to the same limestone forma-
tion, we encountered a Tithonian—Berriasian reef barrier rep-
resented by coral-microbial boundstones.
The shallowing-up trend of the meter-scale cycles is still
maintained in the upper part of the sections, with the high-en-
ergy open marine shoals being covered by lagoonal environ-
ments. The great thickness of the high-energy, open marine
deposits, and the abrupt backstepping of facies (migration of
the platform rim toward platform interior) in the upper part of
the sections, implies a rapid growth of the accommodation
space. This may be related to a maximum flooding on the
long-term sea-level evolution (Strasser & Hillgärtner 1998).
The upward shallowing indicates that sedimentation kept
pace with the created accommodation space.
Conclusions
The carbonate deposits from the Vâlcan Mountains have
been analysed from a sedimentological and biostratigraphic
point of view; lithofacies types, fossil assemblages, and their
vertical distributions have been defined.
We have identified six microfacies types (MFT 1—MFT 6)
within these deposits, based on biotic and abiotic compo-
nents, sedimentary structures and textures, and early diage-
netic features with an environmental significance. The
deposits are characteristic of a shallow carbonate platform
that can be further subdivided into an inner, middle, and outer
platform.
The inner platform deposits are represented by tidal flat
deposits and were best developed during the Late Jurassic.
Deposition on the tidal flats occurred in a great variety of
low- and high-energy sub-environments represented by su-
pratidal marshes and disconnected palustrine deposits, inter-
tidal flats, ponds, beaches and possibly channels. They
reflect tropical humid to sub-humid climatic conditions.
These deposits were followed by predominantly middle
platform deposits, developed during the Early Cretaceous.
They were deposited in high-energy and low-energy envi-
ronments formed in protected or semi-protected shallow sub-
tidal conditions. Rudists and small benthic foraminifera were
the main sediment producers during the Early Cretaceous.
The middle platform deposits interfinger, in the upper
parts of the sections, with the outer platform deposits repre-
sented by high-energy bioclastic shoals and their associated
open-marine deposits.
The vertical succession of microfacies reflects cyclic
changes in water depth. They are more visible in successions
from the middle and outer platform where they are arranged
in shallowing-up cycles. These cycles are superimposed on
an overall transgressive trend, testified by the predominance
of the inner platform facies in the Upper Jurassic and the
transition to middle and outer platform facies during the Early
Cretaceous. This long term transgressive trend can be related
to the second-order tectono-eustatic cycle (Vail et al. 1991),
while the superimposed high frequency cycles can be the re-
sult of lower amplitude sea-level oscillations.
Following the micropaleontological study of some new sec-
tions, new biostratigraphic arguments have been added, com-
pleting and improving the few data available. Three
associations of algae and foraminifera have been identified.
The first association is characteristic of the Late Jurassic, the
second points to Berriasian—Valanginian (possibly also Hau-
terivian) age, while the third one indicates the Barremian in-
terval. The identified micropaleontological assemblages can
46
MICHETIUC, CATINCU and BUCUR
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA, 2012, 63, 1, 33—48
also serve comparisons with other Tethyan regions contain-
ing Upper Jurassic—Lower Cretaceous deposits (e.g. Jaffrezo
1980; Soták & Mišík 1993; Bassoulet 1997a).
Acknowledgments: The study is a contribution to the CNC-
SIS Project BD 413. We thank Jean-Pierre Masse for his valu-
able suggestions on the first draft of this manuscript. We are
also grateful to André Strasser and an anonymous reviewer for
their constructive remarks.
References
Adams A.E. 1980: Calcrete profiles in the Eyam limestone (Car-
boniferous) of Derbyshire: petrology and regional significance.
Sedimentology 27, 651—660.
Altiner D. 1991: Microfossil biostratigraphy (mainly foraminifers)
on the Jurassic—Lower Cretaceous carbonate successions in
north-western Anatolia (Turkey). Geol. Romana 27, 167—213.
Arnaud-Vanneau A. 1980: Micropaléontologie, paléoécologie et sédi-
mentologie d’une plate-forme carbonatée de la marge passive de
la Téthys: l’Urgonien du Vercors septentrional et de la Char-
treuse (Alpes occidentales). Géol. Alpine, Mém. 11, 1—874.
Balintoni I. 1997: Geotectonica terenurilor metamorfice din România.
Ed. Carpatica, Cluj-Napoca, 1—176.
Balintoni I., Berza T., Hann H.P., Iancu V., Krautner H.G. & Uduba a
A. 1989: Precambrian metamorphics in the South Carpathians.
Guide Excursion, Inst. Geol., Geophys., Bucharest, 1—83.
Bassoullet J.-P. 1997a: Foraminif
è
res—Les Grands Foraminif
è
res. In:
Groupe Français d’Étude du Jurassique, Cariou E. & Hantzper-
gue P. (Eds.): Biostratigraphie du Jurassique ouest-européen et
méditerranéen: zonations parall
è
les et distribution des in-
vertébrés et microfossiles. Bull. Cent. Rech. Explor-Prod. Elf-
Aquitaine 17, 293—304.
Bassoullet J.-P. 1997b: Algue Dasycladales – Distribution des prin-
cipales especes. In: Groupe Français d’Étude du Jurassique
(1997), Cariou E. & Hantzpergue P. (coord.): Biostratigraphie
du Jurassique ouest-européen et méditerranéen: zonations par-
all
è
les et distribution des invertébrés et microfossiles. Bull.
Cent. Rech. Explor-Prod. Elf-Aquitaine 17, 339—342.
Bauer J., Kuss J. & Steuber T. 2002: Platform environments, micro-
facies and systems tracts of the Upper Cenomanian—Lower San-
tonian of Sinai, Egypt. Facies 47, 1—26.
Berza T., Krautner H. & Dimitrescu R. 1983: Nappe Structure in the
Danubian Window of the Central-South Carpathians. An. Inst.
Geol. Geof. Rom. 60, 31—38.
Berza T., Balintoni I., Iancu V., Seghedi A. & Hann H.P. 1994: South
Carpathians. Romanian J. Tectonics and Regional Geol. 75, 2,
37—50.
Bouaouda M.S., Barattolo F., Kharrim M.R. & Kamarc A. 2009: Dis-
tribution de Megaporella boulangeri Deloffre & Beun, 1986 (al-
gue dasycladale) dans le Jurassique du bassin atlantique
marocain. Rev. Micropal. 52, 2, 107—122.
Bucur I.I. 1997: Forma iunile mezozoice din zona Re i a-Moldova-
Nouă. Ed. Presa Univ. Clujeană, Cluj, 1—214.
Bucur I.I. 1999: Stratigraphic significance of some skeletal calcare-
ous algae (Dasycladales, Caulerpales) of the Phanerozoic. In:
Farinacci A. & Lord A.R. (Eds.): Depositional episodes and bio-
events. Palaeopelagos, Spec. Publ. 2, 53—104.
Bucur I.I. & Săsăran E. 2005: Relationship between algae and envi-
ronment: an Early Cretaceous case study, Trascău Mountains,
Romania. Facies 51, 274—286.
Bucur I.I., Conrad M.A. & Radoičić R. 1995: Foraminifers and cal-
careous algae from the Valanginian limestones in the Jerma Riv-
er Canyon, Eastern Serbia. Rev. Paléobiologie 14, 2, 349—377.
Burgess P.M. 2006: The signal and the noise: forward modeling of al-
locyclic and autocyclic processes influencing peritidal carbonate
stacking patterns. J. Sed. Res.76, 962—977.
Burne R.V., Bauld J. & De Deckker P. 1980: Saline lake charo-
phytes and their geological significance. J. Sed. Petrology 50,
1, 281—293.
Buurman P. 1980: Palaeosols in the Reading Beds (Palaeocene) of
Alum Bay, Isle of Wight, UK. Sedimentology 27, 593—606.
Camoin G. & Maurin A.-F. 1988: Rôles des micro-organismes
(bactéries, cyanobactéries) dans la g
è
nese des “Mud Mounds”.
Exemple du Turonien des Jebels Bireno et Mrhila (Tunisie).
Comp. Rend. Acad. Sci. 307, 4, 401—407.
Clark G.N. & Boudagher-Fadel M.K. 2002: The larger benthic fora-
miniferal assemblages and stratigraphy of the Late Jurassic
Bhanness complex, Central Lebanon. Rev. Paléobiologie 21,
679—695.
Clavel B., Busnardo R., Charollais J., Conrad M.A. & Granier B.
2010: Répartition biostratigraphique des orbitolinidés dans la
biozonation
à
ammonites (plate-forme urgonienne du Sud-Est de
la France). Partie 1: Hauterivien supérieur—Barrémien basal.
Carnets de Géologie—Notebooks on Geology, Brest, Article
2010/06 (CG2010_A06), 1—53.
Climent-Dom
è
nech H. & Martín-Closas C. 2009: Charophyte-rich
microfacies in the Barremian of the Eastern Iberian Chain
(Spain). Facies 55, 387—400.
Cociuba I. 1997: The presence of the foraminifer Alveosepta jaccardi
(Schrodt) in the Upper Jurassic limestones of Pădurea Craiului
Mountains. In: Dragastan O. (Ed.): Acta Palaeont. Romaniae 1,
221—225.
Cuvillier J., Foury G. & Pignatti Morano A. 1968: Foraminiferes
noveaux du Jurasique superieur du Val Cellina (Frioul occiden-
tal, Italie). Geol. Romana 7, 141—156.
Dahanayake K. 1977: Classification of oncoids from the Upper Juras-
sic carbonates of the French Jura. Sed. Geol. 18, 337—353.
Deloffre R. & Beun N. 1986: Megaporella boulangeri, nouvelle al-
gue dasycladale du Kimmeridgien inferieur Marocain. Rev. Mi-
cropal. 28, 4, 233—242.
Demicco R.V. & Hardie L.A. 1994: Sedimentary structures and early
diagenetic features of shallow marine carbonate deposits. SEPM,
Atlas Ser. 1, 265.
Dupraz C. & Strasser A. 1999: Microbialites and micro-encrusters in
shallow coral bioherms (Middle to Late Oxfordian, Swiss Jura
Mountains). Facies 40, 101—130.
Dupraz C. & Strasser A. 2002: Nutritional modes in coral-microbi-
alite reefs (Jurassic, Oxfordian, Switzerland): Evolution of
trophic structure as a response to environmental change. Palaios
17, 449—471.
Enos P. 1983: Shelf. In: Scholle A.P., Bebour D.G. & Moore C.H.
(Eds.): Carbonate depositional environments. AAPG Mem. 33,
267—296.
Esteban M. & Klappa F.C. 1983: Subaerial exposure. In: Scholle
A.P., Bebour D.G. & Moore C.H. (Eds.): Carbonate depositional
environments. AAPG Mem. 33, 1—54.
Feist M. & Grambast-Fessard N. 1984: New porocharacea from the
Bathonian of Europe: phylogeny and palaeoecology. Palaeon-
tology 27, 2, 295—305.
Flügel E. 2004: Microfacies of carbonate rocks – analysis, inter-
pretation and application. Springer-Verlag, Heidelberg, 1—976.
Fugagnoli A. 2004: Trophic regimes of benthic foraminiferal assem-
blages in Lower Jurassic shallow water carbonates from north-
eastern Italy (Calcari Grigi, Trento Platform, Venetian Prealps).
Palaeogeogr. Palaeoclimatol. Palaeoecol. 205, 111—130.
Gili E. 1992: Palaeoecological significance of rudist constructions: a
case study from Les Collades de Basturs (Upper Cretaceous,
South-Central Pyrenees). Geol. Romana 28, 319—325.
Gili E., Masse J.-P. & Skelton P.W. 1995: Rudists as gregarious sedi-
è
è
è
è
è
à
è
47
PALEOENVIRONMENTAL INTERPRETATION OF THE J/K CARBONATE PLATFORM (ROMANIA)
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA, 2012, 63, 1, 33—48
ment-dwellers, not reef-builders, on Cretaceous carbonate plat-
forms. Palaeogeogr. Palaeoclimatol. Palaeoecol. 118, 245—267.
Ginsburg R.N. 1971: Landward movement of carbonate mud: new
model for regressive cycles in carbonates. Bull. Amer. Assoc.
Petrol. Geol. 55, Abstract, 340.
Ginsburg R.N. 1975: Tidal deposits: a casebook of recent examples
and fossil counterparts. Springer-Verlag, 1—428.
Ginsburg R.N. & Hardie L.A. 1975: Tidal and storm deposits North-
western Andros Island, Bahamas. In: Ginsburg R.N. (Ed.): Tidal
deposits: a casebook of recent examples and fossil counterparts.
Springer-Verlag, 201—208.
Granier B. & Deloffre R. 1993: Inventaire critique des algues dasy-
cladales fossiles. II° partie: Les algues dasycladales du Juras-
sique et du Cretace. Rev. Paléobiologie 12, 1, 19—65.
Grover G. Jr. & Read J.F. 1978: Fenestral and associated vadose di-
agenetic fabrics of tidal flat carbonates, Middle Ordovician New
Market Limestone, southwestern Virginia. J. Sed. Petrology 48,
2, 453—473.
Hottinger L. 1967: Foraminif
è
res imperforés du Mésozo
ï
que ma-
rocain. Notes Mém. Serv. Géol. Maroc 209, 1—168.
Jaffrezo M. 1980: Les formations carbonatées des Corbi
è
res (France)
du Dogger
à
l’Aptien. Micropaléontologie stratigraphique, bio-
zonation, paléoécologie; extension des résultats
à
la Mésogée.
Th
è
se de Doctorat d’Etat
è
Sciences Naturelles, Université P. et
M. Curie, 1—654.
James N.P. & Choquette P.W. 1984: Diagenesis 9. Limestones – the
meteoric diagenetic environment. Geosci. Canada 11, 161—194.
Klappa C.F. 1980: Rizoliths in terrestrial carbonates: classification,
recognition, genesis and significance. Sedimentology 27, 613—629.
Leinfelder R.R., Nose M., Schmid D.U. & Werner W. 1993: Micro-
bial crusts of the Late Jurassic: composition, palaeoecological
significance and importance in reef construction. Facies 29,
195—230.
MacNeil A.J. & Jones B. 2006: Palustrine deposits on a Late Devo-
nian coastal plain-sedimentary attributes and implications for
concepts of carbonate sequence stratigraphy. J. Sed. Res. 76,
292—309.
Mancinelli A. & Coccia B. 1999: Le trocholine dei sedimenti meso-
zoici di piattaforma carbonatica dell’Appennino centro-meridio-
nale (Abruzzo e Lazio). Rev. Paléobiologie 18, 1, 147—171.
Masse J.-P. 1976: Les calcaires urgoniens de Provence. Valanginien—
Aptien inférieur. Stratigraphie, paléontologie, les paléoenviron-
nements et leur évolution. Th
è
se Doct., Marseille 445 p., 124
figs., 11 tabl., 60 pls.
Masse J.-P. 1979: Lower Cretaceous rudists (Hippuriatacea). Paleo-
ecologic approach. Geóbios, Mém. Sp. 3, 277—287.
Masse J.-P. 1992: The Lower Cretaceous Mesogean benthic ecosys-
tems: palaeoecologic aspects and palaeobiogeographic implica-
tions. Palaeogeogr. Palaeoclimatol. Palaeoecol. 91, 331—345.
Masse J.-P. 1995: Lower Cretaceous rudist biostratigraphy of South-
ern France – a reference for Mesogean correlations. Rev. Mex.
Cienc. Geol. 12, 2, 236—256.
Masse J.-P. & Philip J. 1981: Cretaceous coral-rudist buildups of
France. SEPM, Spec. Pub. 30, 399—426.
Masse J.-P., Fenerci M. & Pernarcic E. 2003: Palaeobathymetric re-
construction of peritidal carbonates Late Barremian, Urgonian,
sequences of Provence (SE France). Palaeogeogr. Palaeoclima-
tol. Palaeoecol. 200, 65—81.
Maurin A.F., Bernet-Rollande M.C., Monty C.L.V. & Nazhat S.
1985: The microbial nature of bacinellid textures – sedimento-
logical bearings. 6th European Reg. Meeting of Sedimentology,
Abstracts. Int. Assoc. Sed., 285—287.
McLean D.J. & Mountjoy E.W. 1994: Allocyclic control on Late De-
vonian buildup development, southern Canadian Rocky Moun-
tains J. Sed. Res. 64, 3, 326—340.
Michetiuc M., Catincu C. & Bucur I.I. 2008: Microfacies and mi-
crofossils of the Lower Cretaceous limestones from the south-
ern part of Vâlcan Mountains. Acta Palaeont. Romaniae 6,
217—227.
Neagu T. 1994: Early Cretaceous Trocholina group and some related
genera from Romania. Part I. Rev. Esp. Micropaleont. 26, 3,
117—143.
Oma
ñ
a L. & Arreola C.G. 2008: Late Jurassic (Kimmeridgian)
larger benthic Foraminifera from Santiago Coatepec, SE Puebla,
Mexico. Geobios 41, 6, 799—817.
Pelissié T. & Peybern
è
s B. 1982: Étude micropaléontologique du Ju-
rassique moyen/supérieur du Causse de Limogne (Quercy). De-
scription des foraminif
è
res Trocholina gigantea n. sp.,
Parinvolutina aquitanica n. gen., n. sp. et Limognella dufaurei
n. gen., n. sp. Rev. Micropaleont. 25, 2, 111—132.
Pelissié T., Peybern
è
s B. & Rey J. 1984: Les grands foraminif
è
res
benthiques du Jurassique moyen/superieur du sud-ouest de la
France (Aquitaine, Causses, Pyrénées). Intéręt biostrati-
graphique, paléoécologique et paléobiogéographique. Benthos
’83, 2nd International Symposium on Benthic Foraminifera
(Pau, April 1983), 479—489.
Peryt T.M. 1981: Phanerozoic Oncoids – an overview. Facies 4,
197—214.
Peybern
è
s B. 1976: Le Jurassique et le Crétacé inférieur des Pyrénées
franco-espagnoles entre la Garonne et la Méditerranée. Thése,
Univ. Paul Sabatier-Toulouse, 1—459.
Pittet B., Van Buchem F.S.B., Hillgärtner H., Razin P., Grötsch J. &
Droste H. 2002: Ecological succession, palaeoenvironmental
change, and depositional sequences of Barremian—Aptian shal-
low-water carbonates in northern Oman. Sedimentology 49, 3,
555—581.
Platt H.N. & Wright V.P. 1992: Palustrine carbonates and the Florida
Everglades: towards an exposure index for the fresh-water envi-
ronment. J. Sed. Petrology 62, 6, 1058—1071.
Pop G. 1973: Depozitele mezozoice din Mun ii Vâlcan. Ed. Academi-
ca, Bucure ti, 1—155.
Pop G. & Bucur I.I. 2001: Upper Jurassic and Lower Cretaceous sed-
imentary formations from the Vâlcan mountains (south Car-
pathians). Studia Univ. Babe —Bolyai, Geol. 46, 2, 77—94.
Pratt B.R. & James N.P. 1986: The St. George Group (Lower Ordovi-
cian) of western Newfoundland: tidal flat island model for car-
bonate sedimentation in shallow epeiric seas: Sedimentology 33,
313—343.
Pratt B.R., James N.P. & Cowan C.A. 1992: Peritidal carbonates. In:
Walker R.G. & James N.P. (Eds.): Facies models. Response to
sea level change. Geol. Assoc. Canada, 303—322.
Rankey E.C. & Reeder S.L. 2011: Holocene oolitic marine sand
complexes of the Bahamas. J. Sed. Res. 81, 97—117.
Reolid M., Molina J.M., Löser H., Navarro V. & Ruiz-Ortiz P.A.
2009: Coral biostromes of the Middle Jurassic from the Subbetic
(Betic Cordillera, southern Spain): facies, coral taxonomy,
taphonomy, and palaeoecology. Facies 55, 575—593.
Săsăran E. 2006: Calcarele Jurasicului superior—Cretacicului inferior
din mun ii Trascău. Presa Univ. Clujeană, Cluj-Napoca, 1—249.
Schäffer P. & Senowbari-Daryan B. 1983: Die kalkalgen aus der
Obertrias von Hydra, Griechenland. Paleontographica 185,
83—142.
Schlagintweit F., Gawlick H.-J. & Lein R. 2005: Mikropalaeontolo-
gie und Biostratigraphie der Plassen-Karbonatplatform der Ty-
plokalitaet (Ober-Jura bis Unter-Kreide, Salzkammergut,
Oesterreich. J. Alpine Geol. (Mitt. Gesell. Geol. Bergbaustud.
Österr.) 47, 11—102.
Schlagintweit F., Bover-Arnal T. & Salas R. 2010: New insights into
Lithocodium aggregatum Elliott 1956 and Bacinella irregularis
Radoičić 1959 (Late Jurassic—Lower Cretaceous): two ulvo-
phycean green algae (?Order Ulotrichales) with a heteromorphic
life cycle (epilithic/euendolithic). Facies 56, 509—547.
à
ï
è
è
è
è
à
è
è
ñ
è
è
è
è
48
MICHETIUC, CATINCU and BUCUR
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA
GEOLOGICA CARPATHICA, 2012, 63, 1, 33—48
Schrodt F. 1894: Das Vorkommen der Foraminiferen-Gattung Cycla-
mmina im Oberen Jura. Z. Dtsch. Geol. Gesell. 45, 733—735.
Septfontaine M. 1981: Les Foraminif
è
res imperforés des milieux de
plateforme au Mésozo
ï
que: détermination pratique, interpréta-
tion phylogénétique et utilization biostratigraphique. Rev. Mi-
cropal. 23, 169—206.
Shinn E.A. 1983: Tidal flats. In: Scholle P.A., Bedout D.G. & Moore
C.H. (Eds.): Carbonate depositional environments. AAPG Mem.
33, 171—210.
Shinn E.A. 1986: Modern carbonate tidal flats: their diagnostic fea-
tures. In: Hardie L.A. & Shinn E.A. (Eds.): Carbonate deposition-
al environments: modern and ancient. Part 3. Tidal Flats, 7—35.
Shinn E.A. & Lidz H.B. 1988: Blackened limestone pebbles: fire at
subaerial unconformities. In: James N.P. & Choquette P.W.
(Eds.): Paleokarst. Springer, 117—131.
Shinn E.A. & Robbin D.M. 1983: Mechanical and chemical compac-
tion in fine-grained shallow-water limestone. J. Sed. Petrology
53, 2, 595—618.
Skelton P.W. & Gili E. 1991: Palaeoecological classification of
rudist morphotypes. Proceeding of the 1st International Con-
ference on Rudists (Beograd 1988). Serbian Geol. Soc., Spec.
Publ. 2, 265—287.
Soták J. & Mišík M. 1993: Jurassic and Lower Cretaceous dasyclad-
alean algae from the Western Carpathians. In: Barattolo et al.
(Eds.): Studies on fossil benthic algae. Boll. Soc. Paleont. Ital.,
Spec. Vol. 1, 383—404.
Strasser A. 1984: Black-pebble occurrence and genesis in Holocene
carbonate sediments (Florida Keys, Bahamas, and Tunisia). J.
Sed. Petrology 54, 4, 1097—1109.
Strasser A. 1991: Lagoonal-peritidal sequences in carbonate environ-
ments: autocyclic and allocyclic processes. In: Einsele G.,
Ricken W. & Seilacher A. (Eds.): Cycles and events in stratigra-
phy. Springer-Verlag, 709—721.
Strasser A. & Hillgärtner H. 1998: High-frequency sea-level fluctua-
tions recorded on a shallow carbonate platform (Berriasian and
Lower Valanginian of Mount Sal
è
ve, French Jura). Eclogae
Geol. Helv. 91, 375—390.
Strasser A., Pittet B., Hillgärtner H. & Pasquier J.-B. 1999: Deposi-
tional sequences in shallow carbonate-dominated sedimentary
systems: concepts for a high-resolution analysis. Sed. Geol. 128,
201—221.
Taira A. & Scholle P.A. 1979: Origin of bimodal sands in some mod-
ern environments. J. Sed. Petrology 49, 3, 777—786.
Tasli K. 1993: Micropaléontologie, stratigraphie et environnement de
dépôt des séries jurassiques
à
faci
è
s de plate-forme de la région
de Kale-Gümüshane (Pontides orientales, Turquie). Rev. Micro-
pal. 36, 1, 45—65.
Tucker E. & Wright V.P. 1990: Carbonate sedimentology. Blackwell
Scientific Publ., 1—482.
Vail P.R., Audemard F., Bowman S.A., Eisner P.N. & Perez-Cruz C.
1991: The stratigraphic signatures of tectonics, eustasy and sedi-
mentology – an overview. In: Einsele G., Ricken W. &
Seilacher A. (Eds.): Cycles and events in stratigraphy. Springer,
Berlin, 617—659.
Velić I. 2007: Stratigraphy and palaeobiogeography of Mesozoic
benthic foraminifera of the Karst Dinarides (SE Europe). Geol.
Croatica 60, 1, 1—113.
Védrine S., Strasser A. & Hug W. 2007: Oncoid growth and distribu-
tion controlled by sea-level fluctuations and climate (Late Ox-
fordian, Swiss Jura Mountains). Facies 53, 535—552.
Wilkinson B.H. & Drummond C.N. 2004: Facies mosaics across the
Persian Gulf and around Antigua – stochastic and deterministic
products of shallow-water sediment accumulation. J. Sed. Res.
74, 513—526.
Wilson J.L. 1975: Carbonate facies in geologic history. Springer-
Verlag, 1—471.
Wright V.P. 1986a: Pyrite formation and the drowning of a palaeosol.
Geol. J. 22, 2, 139—149.
Wright V.P. 1986b: The role of fungal biomineralization in the for-
mation of Early Carboniferous soil fabrics. Sedimentology 33,
831—838.
Wright V.P. 1990: Lacustrine carbonates. In: Tucker E. & Wright
V.P. (Eds.): Carbonate sedimentology. Blackwell Scientific
Publ., 164—190.
Wright V.P. & Burgess P.M. 2005: The carbonate factory continu-
um, facies mosaics and microfacies: an appraisal of some of
the key concepts underpinning carbonate sedimentology. Facies
51, 17—23.
Wright V.P. & Tucker E. 1991: Calcretes. Int. Assoc. Sed., Reprint
Ser. 2, 352.
Wright V.P., Platt N.H. & Wimbledon W.A. 1988: Biogenic laminar
calcretes: evidence of calcified root-mat horizons in paleosols.
Sedimentology 35, 603—620.
Wright V.P., Taylor K.G. & Beck V.H. 2000: The paleohydrology of
Lower Cretaceous Seasonal Wetlands, Isle of Wight, Southern
England. J. Sed. Res. 70, 3, 619—632.
è
è
ï
à
è