GeolCarp_Vol61_No5_383

www.geologicacarpathica.sk

GEOLOGICA CARPATHICA, OCTOBER 2010, 61, 5, 383—391 doi: 10.2478/v10096-010-0023-2

Introduction

Studies in biostratigraphy and chronostratigraphy of Meso-
zoic marine sedimentary strata in Tibetan Tethyan Himala-
yas are relatively scarce, in spite of geological studies of this
region extending back more than a century, from early stud-
ies by Hayden (1907) and Douvill

(1916) to later research

(e.g. Yang et al. 1962; Wang et al. 1976; Wu et al. 1977; Wu
1984, 1987; Xu et al. 1990; TBGMR 1993, 1994, 1997). The
main reason is only occasional occurrence of macro- and mi-
crofossils  in  these  Mesozoic  sedimentary  rocks.  Within  the
Mesozoic System, the Upper Cretaceous strata have relative-
ly higher bio- and chronostratigraphic resolution (Wan et al.
1993; Willems & Zhang 1993a,b; Willems et al. 1996; Shi et
al. 2006), mainly based on foraminiferal, calcareous nanno-
fossil  and  stable  isotope  studies  (Wan  et  al.  2003;  Li  et  al.
2006; Shi et al. 2006; Wendler et al. 2009). Most of the bios-
tratigraphic  research  was  conducted  in  the  Gamba  and  Tin-
gri,  areas  that  tectonically  belong  to  the  paleoshelf  of  the
Indian  continental  plate  (Fig. 1).  Six  nannofossil  zones  and
five  additional  biohorizons  spanning  Middle  Albian  up  to
Late Santonian age have been established in the Gamba area
(Zhong et al. 2000). However, from the Cretaceous strata de-
posited  on  the  deeper  continental  slope  of  the  Indian  plate
and in the adjacent oceanic basin floor, as represented by ar-
eas  of  Northern  Tethyan  Himalayas  (see  Fig. 1),  poor  bios-
tratigraphic  data  are  available  up  to  now.  The  exception  is
the Upper Cretaceous strata in the Gyangze area, where sedi-
ments  were  deposited  on  the  lower  continental  slope,  or  at
the transition into the deep oceanic trench (Li et al. 1999; Hu

Nannofossil biostratigraphy of the Lower Cretaceous Shadui

Formation (Northern Tethyan Himalayas, Southern Tibet)

LILIAN ŠVÁBENICKÁ

, XIANGHUI LI

, LUBOMÍR F. JANSA

and YUSHUAI WEI

Czech Geological Survey, Klárov 131/3, 118 21 Praha, Czech Republic; lilian.svabenicka@geology.cz

Department of Earth Sciences, Nanjing University, Nanjing, China; seanlee@nju.edu.cn

Geological Survey of Canada-Atlantic, Dartmouth, N.S., Canada; lujansa@nrcan.gc.ca

Research Center for Tibetan Plateau Geology, Beijing University of Geosciences, Beijing, China; cdutwys@163.com

(Manuscript received September 22, 2009; accepted in revised form March 24, 2010)

Abstract: Calcareous nannofossils of Aptian-Albian age were found in the basal part of the Shadui Formation, North-
ern Tethyan Himalayas, Southern Tibet. The predominantly shale strata are exposed near the northeastern tip of Yamdrock
Tso Lake at the locality of Bangbu and they were previously considered to be of Late Cretaceous age. Occurrence of the
nannofossil species Prediscosphaera columnata and Cribrosphaerella ehrenbergii indicates the Upper Aptian—Lower
Albian Zone BC23. Nannofossil species of Late Albian, Cenomanian or younger Cretaceous age were not present in the
studied part of the Shadui Formation. Nannofossils are badly preserved and hardly identifiable probably as a result of
strong post mortem etching and dissolution during burial. The depositional setting of the Shadui Formation is inter-
preted as hemipelagic to pelagic. A horizon of dark shale in the lower part of the Shadui Formation may be stratigraphically
correlated with ocean anoxic event OAE1b. The discovery of calcareous nannofossils at the Bangbu locality increases
the stratigraphic precision in the correlation of Cretaceous strata between hemipelagic-pelagic facies and shelf deposi-
tional areas in the Tibetan Tethyan Himalayas.

Key words: Lower Cretaceous, Northern Tethyan Himalayas, Shadui Formation, biostratigraphy, oceanic anoxic event,
calcareous nannofossils.

et al. 2008). Despite the overlying sediments being pelagic red
beds intercalated with radiolarites and deposited below CCD
(carbonate dissolution level), the presence of frequent lime-
stone olistoliths and turbidites containing pelagic foraminifers
allowed recognition of the Late Cretaceous age (Wang et al.
1983, 2000; Li et al. 2005; Hu et al. 2006).

Geological setting

The Tethyan Himalayas (Gansser 1964) tectonically be-

long to the Indian continental plate and are generally subdi-
vided  into  Southern  and  Northern  Tethyan  Himalayas  (see
Fig. 1).  The  line  of  subdivision  has  been  placed  along  the
Gyrong-Kangmar thrust (Ratschbacher et al. 1994), or alter-
natively  along  the  Gamba-Tingri  fault  (Wang  et  al.  1996).
The Southern Tethyan Himalayas are characterized by shal-
low shelf sedimentary rocks of the Paleozoic, Mesozoic and
Cenozoic  (up  to  Eocene)  age  (Yang  &  Wu  1962;  Xu  et  al.
1990; Willems et al. 1996), while the Northern Tethyan Hi-
malayas are represented by sediments deposited on the conti-
nental slope and in the adjacent deep oceanic basin (Searle et
al.  1987;  Liu  &  Einsele  1994;  Jadoul  et  al.  1998;  Hu  et  al.
2008). The Bangbu section tectonically belongs to the deep-
er, Northern Tethyan Himalayas (see Fig. 1).

The Bangbu section is located approximately 20 km SW

from Qingjie town, Shannan District, Southern Tibet. The
Mesozoic sedimentary strata are exposed near the northeast-
ern corner of the Yamdrock Tso (see Fig. 1). The base of the
exposed strata is located at E 91°32

’27.4” latitude and N

385

LOWER CRETACEOUS NANNOFOSSIL BIOSTRATIGRAPHY (SHADUI FORMATION, SOUTHERN TIBET)

upper part of the exposed strata few fine-grained feldspathic-
lithic sandstones and cherts are intercalated. Locally, calcar-
eous shale is interbedded with thin-bedded marlstone and/or
mudstone  with  an  appearance  of  high-frequency  cycles  re-
sembling Milankovitch orbitally forced cyclicity. Dark grey
shale is a distinct feature of Bed 2 (Fig. 3). Fragments of bra-
chiopods, foraminifers, rare radiolarians and ostracods found
in this section from Beds 3, 5, 7 and 11, were interpreted as
indicating an Early Cretaceous age (TBGMR 1997), or Late
Cretaceous age (Mao et al. 2003). The later dating is based
on  nannofossils,  namely  an  association  of  Lithastrinus-Bis-
cutum-Prediscosphaera found in three samples (two samples
from Bed 5 and one sample from Bed 8, see Fig. 3). This in-
dicates  that  the  Upper  Cretaceous  strata  at  Bangbu  locality
are much thicker than in the Tingri (Willems et al. 1996; Shi
et al. 2006) and Gyangze areas (Li et al. 2005). Because dur-
ing the field work small faults and folds indicating thrusting
were  noted  and  the  possibility  of  tectonic  duplication  of
parts  of  section  was  highly  probable,  only  Beds 1  and  2  of
the section have been remeasured and sampled for this study.

Methods

For nannofossil study, twenty-two shale samples (for loca-

tion see Fig. 4) were investigated in the fraction of 2—30 µm,
separated  by  decantation  following  the  methodology  de-
scribed in Svobodová et al. (2004). Simple smear-slides were
mounted by Canada Balsam and inspected at 1000  magnifi-
cation,  using  an  oil-immersion  objective  on  a  Nikon  Micro-
phot-FXA transmitting light microscope. Biostratigraphic data
were  interpreted  applying  Sissingh  (1977)  CC  zones,  Roth
(1978) NC zones, and Bown et al. (1998) BC zones.

Results

Sedimentary rocks collected from the lower part of the Sha-

dui Formation, Bangbu section, Beds 1 and 2 (Figs. 3 and 4)
yielded few calcareous nannofossils, with a density from more
than 15 specimens per 1 field of view of the microscope to
less than 1 specimen per 10 fields of view of the microscope.

The nannofossils were poorly preserved, strongly etched and
mostly fragmented (Fig. 5), so the majority of them could not
be  identified.  Assemblages  are  characterized  by  low  species
diversity, high numbers of Watznaueria barnesiae, and by the
remains of outer rims of other placoliths. Biostratigraphically
important species were scarce, irregular and usually fragmented
(Table 1 and Fig. 5). Nannofossil species Prediscosphaera co-
lumnata  (Fig. 5.1,2),  Lithastrinus  floralis,  Helenea  chiastia,
Zeugrhabdotus  embergerii,  and  Lithraphidites  carniolensis
were present only in few samples. The stratigraphically inter-
esting  species  Cribrosphaerella  ehrenbergii  (Fig. 5.4,5)  was
found  in  samples  LL-011  and  LL-041  and  a  questionable
specimen of Rhagodiscus cf. achlyostaurion (Fig. 5.11) exclu-
sively  in  LL-041.  Some  of  the  samples  did  not  provide  any
calcareous nannofossils (see Fig. 4 and Table 1).

Biostratigraphy

The biostratigraphic study resulted only in general informa-

tion because of extremely poor nannofossil preservation. The
presence of Prediscosphaera columnata indicates Zone BC23
that Bown et al. (1998) correlated with the Lower Albian.
However, this species is reported below the proposed base of
the Albian (Kennedy et al. 2000). Apparently Zone BC23
spans the Aptian-Albian boundary (Bralover et al. 1995).

Nevertheless, the scarce presence of Cribrosphaerella

ehrenbergii  may  highlight  the  Lower  Albian.  Erba  (1988)
mentioned the first occurrence of C. ehrenbergii in the Lower
Albian  above  the  first  P.  columnata  from  the  Umbrian-
Marchean Basin, Central Italy (Tethyan Province), but Bown
et al. (1998) reported it from the Upper Albian and correlated
it  with  the  Boreal  ammonite  Zone  “inflatum”.  The  species
range in Italy is more relevant to the Tethyan Himalayas than
its Boreal first occurrence.

The biostratigraphic significance of Rhagodiscus cf. ach-

lyostaurion  is  questionable.  Cobianchi  et  al.  (1997)  marked
its  first  occurrence  in  the  Upper  Albian  in  the  “Amadeus”
level  in  the  Scisti  a  Fucoidi  Formation,  whereas  Bralower
(1992) and Bown et al. (1998) placed it in the Upper Aptian.
However, the badly preserved material from the Shadui For-
mation makes it difficult to differentiate species R. achlyos-

Fig. 3. Lithostratigraphic profile of the Shadui Formation at Bangbu locality (after Mao et al. 2003, modified) with marked Beds 1—17.
Beds no. 1 and 2 are the intervals investigated during this study. 1 – sandstone; 2 – shale; 3 – calcareous shale; 4 – micritic mudstone;
5 – marlstone; 6 – chert; 7 – lenticular limestone; 8 – position of samples reported by Mao et al. (2003); 9 – Lower Cretaceous, Yu-
langbaijia Group; 10 – Lower—Upper Cretaceous, Shadui Formation.

386

ŠVÁBENICKÁ, LI, JANSA and WEI

Fig. 4. Bangbu section, lower part of the Shadui Formation. Litho-
stratigraphic column of Bed 1 and Bed 2 with indication of collected
samples. 1 – shale, 2 – calcareous shale, 3 – marlstone, 4 – out-
crop covered. Nannoplankton zone after Bown et al. (1998), litho-
stratigraphy after Wang et al. (1983).

taurion from R. angustus, the first occurrence of which is
known also from the Aptian. Nannofossil species with their
first occurrences in the Upper Albian, Cenomanian or
younger Cretaceous stages have not been found here.

The basal part of the Shadui Formation, dated at the Bangbu

locality by nannofossils as Late Aptian to Early Albian, may
be  in  part  the  chronostratigraphic  equivalent  of  the  Upper
Gambadongshang  Formation  in  the  Gamba  area,  Southern
Tethyan Himalayas (Zhong et al. 2000), that spans the inter-
val  Early—Middle  Albian,  Zone  Prediscosphaera  cretacea
(Zhong et al. 2000).

Discussion

The scarcity or even complete absence of calcareous nan-

nofossils in sedimentary strata at the Bangbu locality may be
explained by two different causes:

1. Post mortem dissolution near or below the carbonate

compensation depth (CCD). In that case, their scarce pres-
ence or even absence would indicate deposition in a bathyal
or abyssal paleoenvironment.

2. Carbonate dissolution and etching occurring during sed-

iment burial as a result of liberation of organic acids during
decomposition of organic matter enclosed in the sediments,
or during low grade metamorphosis as a result of deep burial
and subsequently accentuated by overthrust tectonics result-
ing from tectonic compression during and after the Indian-
Asian continental collision.

The studied sediments contained mostly dissolution and me-

chanically  more  resistant  nannofossil  species,  represented  by
placoliths  (generally  disc-like  in  form)  of  genera  Watznaueria
and  Parhabdolithus,  or  cubic-shape  nannofossils  of  the  group
Polycyclolithaceae,  genus  Eprolithus.  A  similar  mode  of  nan-
nofossil preservation with signs of strong etching was observed,
for example, in the Albian and Cenomanian black shales of the
Outer Western Carpathians (Svobodová et al. 2004; Švábenická
2006; Skupien et al. 2009), where etching was interpreted as the
result of carbonate dissolution caused by the releases of carbon
dioxide during oxidation of organic matter. The presence of mi-
critic mudstone intercalated within shales in Bed 3 (see Fig. 3)
of the Shadui Formation indicates that dissolution is not related
to  deposition  below  CCD,  but  most  probably  is  the  result  of
deep  burial  and  dissolution  by  organic  acids.  The  prevailing
shale lithology of the Shadui Formation, the presence of nanno-
fossils, and the occurrence of radiolarians observed in the upper
part of the formation suggest a hemipelagic-pelagic deposition-
al environment.

An important horizon of dark grey to black shale contain-

ing nannofossils of the Late Aptian to Early Albian age was
found within Bed 2 (see Fig. 3). Similar horizons in the

Fig. 5. Calcareous nannofossils of the Bangbu locality (Bed 1 and Bed 2), Shadui Formation, Northern Tethyan Himalayas, Tibet. PPL – plane-
polarized light, XPL – cross-polarized light. For magnification see fig. 2. 1, 2 – Prediscosphaera columnata (outer rim); LL-018. 3 – Predisco-
sphaera ponticula (fragment); LL-035, XPL. 4, 5 – Cribrosphaerella ehrenbergii; LL-041, 4 – PPL, 5 – XPL. 6 – Flabellites oblongus;
LL-004, XPL. 7, 8 – Broinsonia matalosa; LL-041, XPL, 7 – 0º, 8 – 10º. 9, 10 – Helenea chiastia; XPL, 9 – LL-011, 10 – LL-047.
11 – Rhagodiscus cf. achlyostaurion; LL-041, XPL. 12 – Rhagodiscus angustus; LL-41, XPL. 13 – Hexalithus sp.; LL-011, XPL. 14 –
Hayesites irregularis; LL-011, XPL. 15, 16 – Hayesites sp.; LL-047. 17, 18 – Stoverius achylosus (fragments); LL-041, XPL. 19 – Cycla-
gelosphaera argoensis; LL-004, XPL. 20 – Watznaueria barnesae; LL-043, XPL. 21 – Watznaueria britannica; LL-041, XPL.

388

ŠVÁBENICKÁ, LI, JANSA and WEI

Table 1:

Bangbu

section,

lower

part

the

Shadui

Formation,

Northern

thyan

Himalayas.

Distribution

calcareous

nannofossils

and

ostratigraphic

interpretation.

Abundance

nannofossil

taxa:

very

rare

(<1

specimen

per

fields

view),

rare

(1—9

specimens

per 10

fields

view),

few

(>1

specimen

per

field

view).

Estimates

the

abunda

nce

nannofossils

sam-

ples:

= moderate (>10 specimens

per field of view),

= low (10—1 specimens per field of view),

= very low (<1 specimen

per field of view),

fragments.

389

LOWER CRETACEOUS NANNOFOSSIL BIOSTRATIGRAPHY (SHADUI FORMATION, SOUTHERN TIBET)

Western  Tethys  are  considered  to  represent  anoxic  ocean
event OAE1b, also known as the Urbino level by Italian geol-
ogists (Luciani et al. 2007), stratigraphically placed in the Ear-
ly  Albian,  or  the  “Paquier”  organic-rich  event  of  the
lowermost  Albian  age,  of  French  geologists  (Herrle  et  al.
2003; Tsikos et al. 2004), which are isotopically demonstrated
by isotopic positive shift of

org

(age correlations sensu Ogg

et al. 2006). Both of these horizons are mentioned in the litera-
ture as OAE1b. Erba (2004) correlates OAE1b with the lower-
most  Albian.  The  “Paquier”  event  falls  in  Roth’s  (1978)
nannoplankton  Zone  NC8  as  does  the  age  of  the  black  shale
horizon within the lower part of the Shadui Formation. If the
black  shale  horizon  within  Bed 2  at  Bangbu  locality  corre-
sponds to the “Paquier” event, that Herrle et al. (2003) related
to a period of extreme monsoonal forcing, then it would dem-
onstrate  the  expansion  of  the  latter  event  into  the  Eastern
Tethys, although current available literature concludes that the
“Paquier”  event  is  known  only  from  the  Tethys-Atlantic  re-
gion (Tsikos et al. 2003).

Confirmation of the potential synchroniety of the black

shale horizon within Bed 2 at Bangbu locality with the “Pa-
quier” event requires detailed carbon and oxygen isotope
analyses of the Bangbu sequence, neither of which is cur-
rently available.

Conclusion

The calcareous nannofossils found in sedimentary strata at

the Bangbu locality, Northern Tethyan Himalayas, Southern
Tibet are badly preserved and hardly identifiable as a result
of  strong  etching  and  dissolution  that  occurred  during  sedi-
ment  burial.  The  Late  Aptian  to  Early  Albian  age,  Zone
BC23  is  proven  by  the  presence  of  the  species  Predis-
cosphaera  columnata  and  scarce  Cribrosphaerella  ehren-
bergii.  Nannofossil  species  that  first  occur  in  the  Late
Albian,  Cenomanian  or  in  younger  Cretaceous  stages  were
not found. The horizon of dark grey to black shales (Bed 2)
in the lower part of the Shadui Formation suggests the pres-
ence of anoxic ocean event OAE1b in Southern Tibet.

The discovery of calcareous nannofossils at the Bangbu

section in Northern Tethyan Himalayas allows more precise
biostratigraphic dating of the sediments, with a zonal resolu-
tion for the Late Aptian and Early Albian stage and thus as-
sists in the intercorrelation of shelf and hemipelagic to
pelagic strata of Mesozoic age in Southern Tibet.

Acknowledgments:  The  authors  thank  the  National  Basic
Research Program of China (973 Project, 2006CB701401) for
financial support of the field-works and Frank Thomas for re-
viewing  English  language  usage.  They  are  also  thankful  for
the suggestions of reviewers Prof. Robert W. Scott, University
of Tulsa, Prof. Michael Wagreich, University of Vienna, and
Dr.  Xiumian  Hu,  University  of  Nanjing  who  helped  to  im-
prove  the  manuscript.  Study  of  calcareous  nannofossils  was
carried  out  in  the  framework  of  the  Research  Plan  of  the
Czech Geological Survey MZP0002579801 as a contribution
to IGCP Project 463 and 555 “Cretaceous Oceanic Red Beds:

Stratigraphy, Composition, Origins, and Paleoceanographic
and Paleoclimatic Significance”.

References

Bown P.R., Rutledge D.C., Crux J.A. & Gallagher L.T. 1998: Lower

Cretaceous. In: Bown P.R. (Ed.): Calcareous nannofossil bios-
tratigraphy. British Micropalaeont. Soc. London, 86—131.

Bralower T.J. 1992: Aptian-Albian calcareous nannofossil biostratig-

raphy of ODP Site 763 and correlation between high- and low-
latitude zonation. Geophys. Monogr. 70, 245—252.

Bralower T.J., Leckie R.M., Sliter W.V. & Thierstein H.R. 1995: An

integrated Cretaceous microfossil biostratigraphy. In: Berggren
W.A., Kent D.V., Aubry M.-P. & Hardenbol J. (Eds.): Geochro-
nology, time scales and global stratigraphic correlation. SEPM
Spec. Publ. 54, 65—79.

Cobianchi M., Luciani V. & Bosellini A. 1997: Early Cretaceous

nannofossils and planktonic foraminifera from northern Garga-
no (Apulia, southern Italy). Cretaceous Research 18, 249—293.

Douvell

H. 1916: Le Cretace et l’Eocene du Tibet central. Paleont.

Indica 5, 1—52.

Erba E. 1988: Aptian-Albian calcareous nannofossil biostratigraphy

of the Scisti a Fucoidi cored at Piobbico (Central Italy). Riv. Ital.
Paleont. Stratigr. 94, 2, 249—284.

Erba E. 2004: Calcareous nannofossils and Mesozoic oceanic events.

Mar. Micropaleontology 52, 85—106.

Gansser A. 1964: The geology of Himalayas. John Wiley Press, New

York, 1—289.

Hayden H.H. 1907: The geology of the provinces Tsang and Ü in cen-

tral Tibet. Surv. India Mem. 36, 122—201.

Herrle J.O., Pross J., Friedrich O. & Hemleben Ch. 2003: Short-term

environmental changes in the Cretaceous Tethyan Ocean: micro-
paleontological evidence from the Early Albian Oceanic Anoxic
Event 1b. Terra Nova 15, 14—19.

Hu X., Wang Ch., Li X. & Jansa L. 2006: Lithology, environment,

and colourness of the Upper Cretaceous oceanic red-bed in
southern Tibet. China Sci., Ser. D, Earth Sci. 36, 9, 811—821.

Hu X.M., Jansa L. & Wang C.S. 2008: Upper Jurassic—Lower Creta-

ceous stratigraphy in south-eastern Tibet: a comparison with the
western Himalayas. Cretaceous Research 29, 301—315.

Jadoul F., Berra F. & Garzanti E. 1998: The Tethys Himalayan pas-

sive margin from Late Triassic to Early Cretaceous (South Ti-
bet). J. Asian Earth Sci. 16, 173—194.

Kennedy W.J., Gale A.S., Bown P.R., Caron M., Davey R.J.,

Gröcke  D.  &  Wray  D.S.  2000:  Integrated  stratigraphy  across
the Aptian-Albian boundary in the Marnes Bleues, at the Col
de  Prés-Guittard,  Arnayon  (Drôme),  and  at  Tartonne  (Alpes-
de-Haute-Provence), France: a candidate global boundary stra-
totype  section  and  boundary  point  for  the  base  of  the  Albian
Stage. Cretaceous Research 21, 591—720.

Li X.H., Wang C.S., Wan X.Q. & Tao R. 1999: Verification of strati-

graphic sequence and classification of the Chungde cross-sec-
tion at Gyangze, southern Tibet. J. Stratigraphy 23, 3, 303—309
(in Chinese with English abstract).

Li X.H., Wang C.S. & Hu X.M. 2005: Stratigraphy of deep-water

Cretaceous deposits in Gyangze, southern Tibet, China. Creta-
ceous Research 26, 33—41.

Li X.H., Jenkyns H.C., Wang C.S., Hu X.M., Chen X., Wei Y.S.,

Huang Y.J. & Cui J. 2006: Upper Cretaceous carbon- and oxy-
gen-isotope stratigraphy of hemipelagic carbonate facies from
southern Tibet, China. J. Geol. Soc. 162, 2, 37—82.

Liu G. & Einsele G. 1994: Sedimentary history of the Tethyan basin

in the Tibetan Himalayas. Geol. Rdsch. 83, 32—61.

Luciani V., Cobianchi M. & Fabbri S. 2007: The regional record of

390

ŠVÁBENICKÁ, LI, JANSA and WEI

Albian oceanic anoxic events at the Apulian platform margin
(Gargano Promontory, southern Italy). Rev. Micropaleont. 50, 3,
239—251.

Mao G.Z., Wang B. & Zeng Q.G. 2003: New data of nannofossils in

the Shadui Formation in the Yamzho Yumco area, Tibet. Geol.
Bull. China 22, 9, 733—735 (in Chinese with English abstract).

Ogg J.G., Agterberg F.P. & Gradstein F.M. 2006: The Cretaceous pe-

riod. In: Gradstein F.M., Ogg J.G. & Smith A.G. (Eds.): A geo-
logic time scale 2004. Cambridge University Press, Cambridge,
344—383.

Ratschbacher L., Frisch W. & Liu G. 1994: Distributed deformation

in southern and western Tibet during and after the India-Asia
collision. J. Geophys. Res. 99, 19, 917—945.

Roth P.H. 1978: Cretaceous nannoplankton biostratigraphy and

oceanography of the northwestern Atlantic Ocean. Initial Re-
ports of the Deep Sea Drilling Project 44, 731—760.

Searle M.P., Windley B.F., Coward M.P., Cooper D.J.W., Rex A.J.,

Rex D., Li T.D., Xiao X.C., Jian M.Q., Thakur V.C. & Kumar S.
1987: The closing of Tethys and the tectonics of the Himalaya.
GSA Bull. 98, 678—701.

Shi H., Li G., Zhao P.X. et al. 2006: New biostratigraphic materials

of planktic foraminifera of the Upper Cretaceous from Gongzha,
Dingri, southern Tibet, China. J. Chengdu University of Tech-
nology 33, 2, 134—140 (in Chinese with English abstract).

Sissingh W. 1977: Biostratigraphy of Cretaceous calcareous nanno-

plankton. Geol. en Mijnb. 56, 37—65.

Skupien P., Bubík M., Švábenická L., Mikuláš R., Vašíček Z. &

Matýsek  D.  2009:  Cretaceous  oceanic  red  beds  in  the  Outer
Western  Carpathians  of  the  Czech  Republic.  In:  Hu  X.,  Wang
Ch.,  Scott  R.W.,  Wagreich  M.  &  Jansa  L.  (Eds.):  Cretaceous
oceanic  red  beds:  stratigraphy,  composition,  origins,  and  pale-
oceanographic  and  paleoclimatic  significance.  Soc.  Sed.  Geol.,
Tulsa, 99—109.

Svobodová M., Hradecká L., Skupien P. & Švábenická L. 2004: Mi-

crofossils of the Albian and Cenomanian shales from the Štram-
berk area (Silesian Unit, Outer Western Carpathians, Czech
Republic). Geol. Carpathica 55, 5, 371—388.

Švábenická L. 2006: Biostratigraphy and palaeoenvironment of the

“black shales” and “red beds” in the Tethyan foreland basins ac-
cording to study of calcareous nannofossils. In: Hu X.M., Wang
Y. & Huang Y. (Eds.): International Symposium on Cretaceous
Major Geological Events and Earth System in Beijing. Ab-
stracts, 77—79.

TBGMR (Tibet Bureau of Geology and Mineral Resources) 1993: Ti-

betan geology. Geological Publishing House, Beijing, 1—459 (in
Chinese with English abstract).

TBGMR 1994: Report of Geological Mapping (Nangarze,

1 : 200,000). Geological Publishing House, Beijing, 1—256 (in
Chinese).

TBGMR 1997: Lithostratigraphy of Xizang (Tibet) Autonomous Re-

gion. Geological Publishing House, Beijing, 1—302 (in Chinese).

Tsikos H., Karakitsios V., Bombardiere L., Van Breugel Y., Sin-

nighe-Damste J., Schouten S., Farrimond P., Tyson R.V. & Jen-
kyns H.C. 2003: The Oceanic Anoxic Event (OAE) 1B in the
Ionian basin, NW Greece: Organic geochemical evidence. Ab-
stract. Mesozoic Paleoceanography, SGF, 49—50.

Tsikos H., Karakitsios V., Van Bruegel Y., Walsworth-Bell B., Bom-

bardiere L., Petrizzo M.R., Sinninghe Damste J.S., Schouten S.,
Erba E., Premoli Silva I., Farrimond P., Tyson R.V. & Jenkyns

H.C. 2004: Organic-carbon deposition in the Cretaceous of the
Ionian Basin, NW Greece: the paquier event (OAE1b) revised.
Geol. Mag. 141, 401—416.

Wan X., Burnett J. & Gallagher L. 1993: A preliminary correlation

between the Cretaceous calcareous nannofloras and foraminifera
of southern Tibet. Rev. Esp. Micropaleont. 25, 1, 41—56.

Wan X.Q., Wei M. & Li G.B. 2003:

C values from the Cenoma-

nian-Turonian passage beds of southern Tibet. J. Asian Earth
Sci. 21, 8, 861—866.

Wang C.S., Xia D.X., Zhou X., Chen J.P., Lu Y., Wang G.H., He

Z.W.,  Li  X.H.,  Wan  X.Q.,  Zeng  Q.G.,  Pubu  C.R.  &  Liu  Z.F.
1996:    Field  trip  guide  (T121/T387):  Geology  between  the  In-
dus-Yarlung  Zangbo  suture  zone  and  the  Himalaya  Mountains,
Xizang (Tibet), China. Geological Publishing House, 1—72.

Wang C.S., Li X.H., Wan X.Q. & Tao R. 2000: The Cretaceous in

Gyangze, southern Xizang (Tibet): Redefined. Acta Geol. Sinica
74, 2, 97—107 (in Chinese with English abstract).

Wang N.W., Liu G.F. & Chen G.M. 1983: Regional geology in Yam-

drock Tso, Tibet. Contr. Geol. Qinghai-Xizang (Tibet), Ser. 3,
1—20.

Wang Y.G., Wang Y.J. & Wu H.R. 1976: Discussion on the Jiabula

Formation and the discovery of Longzi Lower Jurassic in
southern Xizang, China. Sci. Geol. Sinica 2, 149—156 (in Chi-
nese with English abstract).

Wendler I., Wendler J., Gräfe K.-U., Lehmann J. & Willems H. 2009:

Turonian to Santonian carbon isotope data from the Tethys Hima-
laya, southern Tibet. Cretaceous Research 30, 961—979.

Willems H. & Zhang B.G. 1993a: Cretaceous and lower Tertiary sed-

iments of the Tibetan Tethys Himalayas in the area of Gamba
(South Tibet, PR China). Berichte FB Geowiss. Univ. Bremen
38, 3—27.

Willems H. & Zhang B.G. 1993b: Cretaceous and lower Tertiary sed-

iments of the Tibetan Tethys Himalayas in the area of Tingri
(South Tibet, PR China). Berichte FB Geowiss., Univ. Bremen
38, 28—47.

Willems H., Zhou Z., Zhang B.G. & Grafe K.U. 1996: Stratigraphy of

the Upper Cretaceous and lower Tertiary strata in the Tethyan Hi-
malayas of Tibet (Tingri area, China). Geol. Rdsch. 85, 723—754.

Wu H.R. 1984: Northern region of Tethys-Himalayas. In: Chinese

Academic Institute (Compilers): Stratigraphy in Xizang (Ti-
betan) Plateau. Science Press, Beijing, 115—119 (in Chinese).

Wu H.R. 1987: Late Cretaceous and Tertiary (?) strata in Gyangze,

southern Xizang. J. Stratigraphy 11, 147—149 (in Chinese with
English abstract).

Wu H.R., Wang D.A. & Wang L.C. 1977: Cretaceous in Lhaze-Gy-

angze, southern Xizang. Sci. Geol. Sinica 3, 250—261 (in Chi-
nese with English abstract).

Xu Y.L., Wan X.Q., Gou Z.H. & Zhang Q.H. 1990: Biostratigraphy

of Xizang (Tibet) in the Jurassic, Cretaceous and Tertiary peri-
ods. China University of Geosciences Press, Wuhan, 1—147 (in
Chinese with English abstract).

Yang Z.Y. & Wu S.B. 1962: Stratigraphy and fauna of marine Juras-

sic to Paleogene. In: Chinese Geological Society, Proceedings of
22nd Annual Meeting. Geological Publishing House, Beijing,
66—69 (in Chinese with English abstract).

Zhong S.L., Zhou Z.C., Willems H., Zhang B.G. & Zhu Y.H. 2000:

The middle Cretaceous calcareous nannofossil zones in Gamba
area, southern Xizang (Tibet), China and the Cenomanian-Turo-
nian boundary. Acta Palaeont. Sinica 39, 3, 313—325.