Foraminiferal Biostratigraphy and Palaeoenvironmental Analysis of the Mid-cretaceous Limestones in the Southern Tibetan Plateau

Abstract This study of mid-Cretaceous foraminifera from the Linzhou, the Coqen and the Xigaze Basins in the southern Tibetan Plateau has provided the first high resolution biostratigraphic description of these limestones and interpretation of their paleoenvironmental settings. The fossil assemblages are dominated primarily by orbitolinid larger benthic foraminifera. We reassessed the identification of many taxa, dividing the South Tibetan sedimentary successions of Aptian to Early Cenomanian age into eight new foraminiferal biozones (TLK1 a–h): (i) (TLK1a) a shallow reefal environment corresponding to planktonic foraminifera zone (PZ) Aptian 1–2, dominated by Palorbitolina and Praeorbitolina spp.; (ii) (TLK1b) a transgressive, reefal to forereefal environment corresponding to PZ Aptian 3, characterized by the first appearance of Mesorbitolina parva; (iii) (TLK1c) a shallow reefal to backreef environment of Late Aptian (PZ Aptian 4) age, characterized by the first appearance of Mesorbitolina texana; (iv) (TLK1d) a transgressive phase of forereef to an inner neritic environment of Albian (PZ Albian 1) age, characterized by the first appearance of Cuneolina pavonia; (v) (TLKe) an open-marine reefal environment of Albian (PZ Albian 2) age, with assemblages dominated by flat to slightly conical orbitolinids, characterized by the first appearance of Palorbitolinoides hedini; (vi) (TLK1f) a shallow, open-marine reefal to forereef environment of Middle Albian (PZ Albian 3) age, dominated by flat and convex orbitolinids, and characterized by the first appearance of Mesorbitolina aperta; (vii) (TLK1g) a reefal to forereef environment of end Albian (PZ Albian 4) age, characterized by the appearance of Conicorbitolina cf. cuvillieri and Pseudochoffatella cuvillieri, and in which Early Aptian species of Praeorbitolina cf. wienandsi have been recorded for the first time from the Late Albian; (viii) (TLK1h) a shallow reefal environment of Early Cenomanian age characterized by the first appearance of Conicorbitolina sp. A and Nezzazata conica. The eight new biozones provided biostratigraphic correlation of the Langshan, Sangzugang and Takena Formations in the Lhasa terrane, while the observed evolution of the environmentally controlled microfacies corresponds closely with the current, inferred global sea-level variation of the period. The almost continuous sedimentary sequences studied allowed previously defined orbitolinid phylogenetic linages to be confirmed.

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Evaluating the Water Level Variation of a High-Altitude Lake in Response to Environmental Changes on the Southern Tibetan Plateau

Journal of Hydrologic Engineering ◽

10.1061/(asce)he.1943-5584.0002050 ◽

2021 ◽

Vol 26 (5) ◽

Author(s):

Xuegao Chen ◽

Zhongbo Yu ◽

Qinghan Huang ◽

Peng Yi ◽

Xiaonan Shi ◽

...

Keyword(s):

Tibetan Plateau ◽

High Altitude ◽

Water Level ◽

Environmental Changes ◽

Level Variation ◽

Water Level Variation ◽

Southern Tibetan Plateau ◽

High Altitude Lake

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The Paleogeographic Evolution of the Orthophragminids of the Paleogene

The Journal of Foraminiferal Research ◽

10.2113/gsjfr.47.4.337 ◽

2017 ◽

Vol 47 (4) ◽

pp. 337-357 ◽

Cited By ~ 4

Author(s):

Marcelle K. BouDagher-Fadel ◽

G. David Price

Keyword(s):

South Africa ◽

South African ◽

Planktonic Foraminifera ◽

Late Eocene ◽

Larger Benthic Foraminifera ◽

The Pacific ◽

West African Coast ◽

New Material ◽

Global Sea Level ◽

Definition Of

Abstract Orthophragminids are larger benthic foraminifera (LBF) and, together with the nummulitids, were the major rock-forming foraminifera from the middle Paleocene to the late Eocene. Today, porous, LBF-bearing, Paleogene limestones, which occur globally from the Pacific and Atlantic margins of the Americas to the Indo-Pacific, form potentially valuable oil reservoirs, and their biota have formed the basis of the definition of three paleobiogeographic provinces, namely those of the Americas, Tethys, and the Indo-Pacific. The orthophragminids of the western part of the Tethyan Province have been studied extensively, however, the other provinces are less well characterized, and until now the origin and paleogeographic development of this group have not been fully articulated. New material described here allows the clear definition of a fourth, South African paleobiogeographic province, and, when combined with refined biostratigraphic dating based on new material from the Americas, Europe, South Asia and SE Asia, enables their paleogeographic and biostratigraphic evolution to be determined. Critically, the occurrence of cosmopolitan planktonic foraminifera (PF) within LBF assemblages enables the first occurrences of various LBF forms within each province to be dated relative to well-calibrated planktonic zones (PZ). From this, we infer that, like the previously studied lepidocyclinids and nummulitids, the orthophragminids originated in the Americas during the Paleocene, probably between the late Danian (PZ P1c, 63.5 Ma) and the early Selandian (PZ P3a, 61.6 Ma). By the middle Paleocene, the orthophragminids had migrated across the Atlantic to the previously isolated West African coast at the extreme of Tethys, probably during global sea-level low stands at 60.3 Ma and again at 56.4 Ma. Subsequently, the American Province again became isolated. In the Tethys, the orthophragminid migrations followed two paths: northeastward through the Tethyan corridor in the late Paleo-cene (Thanetian), and south in the earliest Eocene (Ypresian) to South Africa. The Tethyan forms evolved during the Eocene into many lineages, which in turn migrated, after a few million years of their first appearances into the Indo-Pacific, where they again became isolated and diversified further. Meanwhile the South African forms remained similar to their American ancestors in both small size and external ornamentation, while their internal evolution closely followed that of Tethys forms, as exhibited by three species of Nemkovella and Discocyclina described here from South Africa (Nemkovella mcmilliana n. sp., Discocyclina davyi n. sp. and D. africana n. sp.).

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<i>Bolboforma</i> (Phytoplankton Incertae Sedis), <i>Bachmayerella</i> and other Calciodinelloidea (Phytoplankton) from the Middle Miocene of the Alpine–Carpathian Foredeep (Central Paratethys)

Journal of Micropalaeontology ◽

10.1144/jm.23.2.139 ◽

2004 ◽

Vol 23 (2) ◽

pp. 139-152 ◽

Cited By ~ 5

Author(s):

Silvia Spezzaferri ◽

Fred Rögl

Keyword(s):

Middle Miocene ◽

Planktonic Foraminifera ◽

High Latitudes ◽

Calcareous Nannofossils ◽

Geological Time ◽

Incertae Sedis ◽

Sedimentary Sequences ◽

Unicellular Organisms ◽

First Time

Abstract. Bolboforma is a microfossil of uncertain origin with affinities to protophytic algae. It generally occurs at high latitudes and/or in cool and temperate waters and has a high stratigraphic potential especially for the Miocene. Calcareous cysts of dinoflagellates represent the ‘benthic cyst stage’ of unicellular organisms belonging to the marine phytoplankton.The occurrence of Bolboforma, Bachmayerella is documented here and, for the first time, some calcareous cysts of dinoflagellates tentatively attributed to Alasphaera and Pithonella from Badenian (Langhian–Middle Miocene) sediments in Austrian and Moravian localities. Alasphaera and Pithonella were previously described from Cretaceous and Danian sediments only, therefore, their range has been extended into the Paratethyan Middle Miocene.Correlation of Bolboforma bioevents with standard geological time-scales allows confirmation, and in some cases refinement, of age assignments based on other microfossil groups, such as foraminifera and calcareous nannofossils, in Paratethyan areas. In particular, this paper presents a case study of the biostratigraphy of the Grund Formation outcropping at its type locality in Lower Austria. Age attribution of the Grund Formation has been uncertain for some time. The recovery of Praeorbulina glomerosa circularis and Uvigerina macrocarinata, associated with Bolboforma reticulata, allows the correlation of the Grund Formation with the Early Badenian (Middle Miocene). As planktonic foraminifera are generally very rare or absent in shelf deposits of many other Austrian and Moravian Middle Miocene sedimentary sequences, Bolboforma, and in particular B. reticulata, remains an important biomarker to identify lower Badenian sediments.Additionally, the new species Bolboforma gneixendorfensis Spezzaferri & Rögl is described. It is generally double-chambered with a weakly reticulate wall texture and is associated with Bolboforma reticulata, B. bireticulata and/or B. moravica.

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The Geographic, Environmental and Phylogenetic Evolution of the Alveolinoidea from the Cretaceous to the Present Day.

10.14324/111.444/000057.v2 ◽

2020 ◽

Author(s):

Marcelle Boudagher-Fadel ◽

Geoffrey David Price

Keyword(s):

Sea Level ◽

Convergent Evolution ◽

Systematic Analysis ◽

Larger Benthic Foraminifera ◽

Shallow Marine ◽

Marine Carbonates ◽

New Material ◽

Phylogenetic Evolution ◽

Global Sea Level ◽

First Time

The superfamily Alveolinoidea is a member of the Order Miliolida, and is comprised of three main families, the Alveolinidae, the Fabulariidae and the Rhapydioninidae. They are examples of Larger Benthic Foraminifera (LBF), which are single cell organisms with specific characteristic endoskeletons. Alveolinoids are found globally from the Cretaceous to present day and are very important biostratigraphic index fossils in shallow-marine carbonates. They are often associated with significant hydrocarbon reservoirs, and exhibit provincialism with characteristic genera often confined to one of the American, Tethyan or Indo-Pacific provinces. Previously, the systematic study of the global interrelationship between the various alveolinoid lineages has not been possible because of the absence of biostratigraphic correlation between the geographically scattered assemblages, and the scarcity of described material from the Indo-Pacific province. Here we use the literature and new material from the Americas, the French Alps, Iran, Tibet, India and SE Asia, coupled with the use the planktonic foraminiferal zonal (PZ) correlation scheme to put forward, for the very first time, a comprehensive, global, systematic analysis of the biostratigraphic, phylogenetic and palaeogeographic evolution of the alveolinoids. The alveolinoids originated in the Cretaceous in the Tethyan province. During a global sea-level low-stand, a westward migration of some alveolinoids species to the Americas occurred in this period, a behaviour also seen in previous studies of contemporaneous orbitolinid LBF. After the K-P event, which saw the extinction of all Cretaceous alveolinoids, rare new forms of alveolinoids evolved again, first in the Americas and later independently in Tethys. As found in previous studies of rotalid LBF, sea-level low-stands in the Paleocene also allowed some alveolinoid forms to migrate, but this time in an eastward direction from the Americas to Tethys, and from Tethys on to the Indo-Pacific. Alveolinoids still exist today ( Borelis and Alveolinella ), the former of which is cosmopolitan, while the latter is restricted to the Indo-Pacific province. Throughout their phylogenetic history alveolinoids characteristically exhibit convergent evolution, with the repeated re-occurrence of certain morphological features. Understanding this propensity to homoplasy is essential in understanding and constructing the phylogenetic relationships within the alveolinoid superfamily.

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The Geographic, Environmental and Phylogenetic Evolution of the Alveolinoidea from the Cretaceous to the Present Day.

10.14324/111.444/000057.v1 ◽

2020 ◽

Author(s):

Marcelle Boudagher-Fadel ◽

Geoffrey David Price

Keyword(s):

Sea Level ◽

Convergent Evolution ◽

Systematic Analysis ◽

Larger Benthic Foraminifera ◽

Shallow Marine ◽

Marine Carbonates ◽

New Material ◽

Phylogenetic Evolution ◽

Global Sea Level ◽

First Time

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The Geographic, Environmental and Phylogenetic Evolution of the Alveolinoidea from the Cretaceous to the Present Day.

10.14324/111.444/000057.v3 ◽

2021 ◽

Author(s):

Marcelle Boudagher-Fadel ◽

Geoffrey David Price

Keyword(s):

Sea Level ◽

Convergent Evolution ◽

Systematic Analysis ◽

Larger Benthic Foraminifera ◽

Shallow Marine ◽

Marine Carbonates ◽

New Material ◽

Phylogenetic Evolution ◽

Global Sea Level ◽

First Time

The superfamily Alveolinoidea is a member of the Order Miliolida, and is comprised of three main families, the Alveolinidae, the Fabulariidae and the Rhapydioninidae. They are examples of Larger Benthic Foraminifera (LBF), which are single cell organisms with specific characteristic endoskeletons. Alveolinoids are found globally from the Cretaceous to present day and are very important biostratigraphic index fossils in shallow-marine carbonates. They are often associated with significant hydrocarbon reservoirs, and exhibit provincialism with characteristic genera often confined to one of the American, Tethyan or Indo-Pacific provinces. Previously, the systematic study of the global interrelationship between the various alveolinoid lineages has not been possible because of the absence of biostratigraphic correlation between the geographically scattered assemblages, and the scarcity of described material from the Indo-Pacific province. Here we use the literature and new material from the Americas, the French Alps, Iran, Tibet, India and SE Asia, coupled with the use the planktonic foraminiferal zonal (PZ) correlation scheme to put forward, for the very first time, a comprehensive, global, systematic analysis of the biostratigraphic, phylogenetic and palaeogeographic evolution of the alveolinoids. The alveolinoids originated in the Cretaceous in the Tethyan province. During a global sea-level low-stand, a westward migration of some alveolinoids species to the Americas occurred in this period, a behaviour also seen in previous studies of contemporaneous orbitolinid LBF. After the K-P event, which saw the extinction of all Cretaceous alveolinoids, rare new forms of alveolinoids evolved again, first in the Americas and later independently in Tethys. As found in previous studies of rotalid LBF, sea-level low-stands in the Paleocene also allowed some alveolinoid forms to migrate, but this time in an eastward direction from the Americas to Tethys, and from Tethys on to the Indo-Pacific. Alveolinoids still exist today ( Borelis and Alveolinella), the former of which is cosmopolitan, while the latter is restricted to the Indo-Pacific province. Throughout their phylogenetic history alveolinoids characteristically exhibit convergent evolution, with the repeated re-occurrence of certain morphological features. Understanding this propensity to homoplasy is essential in understanding and constructing the phylogenetic relationships within the alveolinoid superfamily.

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