The marine early\|middle Early Paleogene in the northern Tethys Himalayas was found in southern Tibet in mid 1980s (Hao and Wan, 1985), and the bio\|, litho\|, and chrono\| stratigraphy were patterned by then (Hao and...The marine early\|middle Early Paleogene in the northern Tethys Himalayas was found in southern Tibet in mid 1980s (Hao and Wan, 1985), and the bio\|, litho\|, and chrono\| stratigraphy were patterned by then (Hao and Wan, 1985; Willems et al., 1993, 1996). It seems that there is not an abrupt boundary between the Paleocene and Eocene (P/E) because they are composed of carbonate rocks. This similarity is widespread in the world. They are well examined in many ocean DSDP and ODP logs in similar continuous sediments. But in fact, it is sure that there is a geologic event between the Paleocene and Eocene around the world. Foraminifer extinction, stable isotope record, clay mineral changes, etc. verify the geologic event existence at the latest Paleocene. Unlike the K/T boundary, there is at present little direct or indirect evidence of such catastrophes coincident with the transition (Zachos et al., 1993). This work first shows that there could be also a geologic event across the boundary of latest Paleocene to earliest Eocene exposed on land, certainly in China territory.The P/E transitional sediment is exposed and remeasured at Gongzha, northwestern flank of the Zhepure Shan Syncline, west to Tingri. Here the P/E transitional stratum is approximately equivalent to the upper Member IV and the entire Member V (Willems et al., 1993, 1996). The exact boundary between the Paleocene and Eocene, i.e. between the Unit 16 and Unit 17, is determined by benthic foraminiferal zonations. The fossil zone Alveolina beginning at Unit 17 is just above the boundary that is partly different from Willems et al (1993, 1996).展开更多
The marine non\|carbonate sediment is exposed at the southwestern flank of the Zhepure Syncline where it lies about 4 km east to the typical cross\|section, Gongzha cross\|section (Hao and Wan, 1985; Willems et al., 1...The marine non\|carbonate sediment is exposed at the southwestern flank of the Zhepure Syncline where it lies about 4 km east to the typical cross\|section, Gongzha cross\|section (Hao and Wan, 1985; Willems et al., 1993, 1996) and ca.75km north to the Qomolangma. There are few people who can approach the place of the cross\|section, even so are endemic Tibetan. The cross\|section is named of the Qumiba cross\|section in this abstract. The new discovery, conformed on the massive Zhepure Formation limestone, here is named of Qumiba Formation. It is composed of two series of terrigenous sediments: Enba Member—lower gray shales intercalating with sandstones, and Zhaguo Member—upper reddish shales interbedding with sandstones. Abundant nannofossils with chronological meanings are first found out.Enba Member Common calcareous nannofossils in the Lutetian such as Chiastozygus barbatus, Chiasmolithus sp., Discoaster barbadiensis, Helicosphaera compacta, Reticulofenstra bisecta, Sphenolithus radians are processed in sample S12W1\|S17W1, in which the Helicosphaera compacta and Sphenolithus radians are part of the indicators of the nannofossil zone NP15. So it is proposed that Units S12\|17, 110 m in thickness, could have been deposited during Middle\|Late Lutetian.展开更多
A section in the Zhepure Mountains near Old Tingri in SE-Tibet,ranging from the Upper Albian to Paleogene,was described in detail by Willems et al.(1996).These authors worked on the litho-and microfacies and set up th...A section in the Zhepure Mountains near Old Tingri in SE-Tibet,ranging from the Upper Albian to Paleogene,was described in detail by Willems et al.(1996).These authors worked on the litho-and microfacies and set up the biostratigraphical framework by planktonic foraminifera.Willems et al.(1996)established their section as a standard for southern Tibet and compared it to the Gamba area.During the 2004 Tibet-expedition of Chengdu University of Technology in China,in co-operation with Bremen and Kiel universities in Germany,the locality was revisited for the purpose of collecting invertebrate fossils.This field-work included only the Upper Cretaceous part of the Tingri section and its invertebrate faunal content.Until today almost no ammonite and inoceramid data existed for this section.This is true for most Cretaceous sections in Tibet,although the Upper Cretaceous succession was interpreted as shelf environment.which in other parts of the world contains rich faunas of these macrofossil groups.The newly discovered continuous record of rare ammonites and inoceramids is probably limited since the preservation in the wacke-and packstones is poor.In addition,sampling conditions were unfavorable and the environmental conditions disadvantageous for most groups of invertebrates,as possibly indicated by larger amounts of small bivalve debris(filaments)in the upper part of the Gamba Group.Although the collected fauna is sparse and poorly preserved,the following biostratigraphical data can be added to the hitherto described microfauna:Calycoceras?from the Upper Gamba Group is Late Cenomanian in age and is accompanied by indeterminable juvenile desmoceratids.Superjacent follows a record of the ammonite Forresteria sp.,indicating that this level in the upper part of the Gamba Group belongs to the Lower Coniacian.This supports the finding of Inoceramus(Cremnoceramus)waltersdorfensis?hannovrensis?from the same interval.Anagaudryceras?is an individual ammonite finding from the Zhepure Shanbei or Zhepure Shanpo Formation,corresponding to the Santonian-Maastrichtian part of the succession.展开更多
The Cyclostratigraphy study is increasingly important in the precise dating of the marine strata, especially in the Tethyan realm.Compared with the Western Tethys,the Cyclostratigraphy study on the Eastern Tethys is r...The Cyclostratigraphy study is increasingly important in the precise dating of the marine strata, especially in the Tethyan realm.Compared with the Western Tethys,the Cyclostratigraphy study on the Eastern Tethys is relatively insufficient.Cretaceous marine sediments are cropped out widely in Southern Tibet,among them the late Cretaceous in the Gongzha section of Tingri area is rather continuous and integral.展开更多
文摘The marine early\|middle Early Paleogene in the northern Tethys Himalayas was found in southern Tibet in mid 1980s (Hao and Wan, 1985), and the bio\|, litho\|, and chrono\| stratigraphy were patterned by then (Hao and Wan, 1985; Willems et al., 1993, 1996). It seems that there is not an abrupt boundary between the Paleocene and Eocene (P/E) because they are composed of carbonate rocks. This similarity is widespread in the world. They are well examined in many ocean DSDP and ODP logs in similar continuous sediments. But in fact, it is sure that there is a geologic event between the Paleocene and Eocene around the world. Foraminifer extinction, stable isotope record, clay mineral changes, etc. verify the geologic event existence at the latest Paleocene. Unlike the K/T boundary, there is at present little direct or indirect evidence of such catastrophes coincident with the transition (Zachos et al., 1993). This work first shows that there could be also a geologic event across the boundary of latest Paleocene to earliest Eocene exposed on land, certainly in China territory.The P/E transitional sediment is exposed and remeasured at Gongzha, northwestern flank of the Zhepure Shan Syncline, west to Tingri. Here the P/E transitional stratum is approximately equivalent to the upper Member IV and the entire Member V (Willems et al., 1993, 1996). The exact boundary between the Paleocene and Eocene, i.e. between the Unit 16 and Unit 17, is determined by benthic foraminiferal zonations. The fossil zone Alveolina beginning at Unit 17 is just above the boundary that is partly different from Willems et al (1993, 1996).
文摘The marine non\|carbonate sediment is exposed at the southwestern flank of the Zhepure Syncline where it lies about 4 km east to the typical cross\|section, Gongzha cross\|section (Hao and Wan, 1985; Willems et al., 1993, 1996) and ca.75km north to the Qomolangma. There are few people who can approach the place of the cross\|section, even so are endemic Tibetan. The cross\|section is named of the Qumiba cross\|section in this abstract. The new discovery, conformed on the massive Zhepure Formation limestone, here is named of Qumiba Formation. It is composed of two series of terrigenous sediments: Enba Member—lower gray shales intercalating with sandstones, and Zhaguo Member—upper reddish shales interbedding with sandstones. Abundant nannofossils with chronological meanings are first found out.Enba Member Common calcareous nannofossils in the Lutetian such as Chiastozygus barbatus, Chiasmolithus sp., Discoaster barbadiensis, Helicosphaera compacta, Reticulofenstra bisecta, Sphenolithus radians are processed in sample S12W1\|S17W1, in which the Helicosphaera compacta and Sphenolithus radians are part of the indicators of the nannofossil zone NP15. So it is proposed that Units S12\|17, 110 m in thickness, could have been deposited during Middle\|Late Lutetian.
文摘A section in the Zhepure Mountains near Old Tingri in SE-Tibet,ranging from the Upper Albian to Paleogene,was described in detail by Willems et al.(1996).These authors worked on the litho-and microfacies and set up the biostratigraphical framework by planktonic foraminifera.Willems et al.(1996)established their section as a standard for southern Tibet and compared it to the Gamba area.During the 2004 Tibet-expedition of Chengdu University of Technology in China,in co-operation with Bremen and Kiel universities in Germany,the locality was revisited for the purpose of collecting invertebrate fossils.This field-work included only the Upper Cretaceous part of the Tingri section and its invertebrate faunal content.Until today almost no ammonite and inoceramid data existed for this section.This is true for most Cretaceous sections in Tibet,although the Upper Cretaceous succession was interpreted as shelf environment.which in other parts of the world contains rich faunas of these macrofossil groups.The newly discovered continuous record of rare ammonites and inoceramids is probably limited since the preservation in the wacke-and packstones is poor.In addition,sampling conditions were unfavorable and the environmental conditions disadvantageous for most groups of invertebrates,as possibly indicated by larger amounts of small bivalve debris(filaments)in the upper part of the Gamba Group.Although the collected fauna is sparse and poorly preserved,the following biostratigraphical data can be added to the hitherto described microfauna:Calycoceras?from the Upper Gamba Group is Late Cenomanian in age and is accompanied by indeterminable juvenile desmoceratids.Superjacent follows a record of the ammonite Forresteria sp.,indicating that this level in the upper part of the Gamba Group belongs to the Lower Coniacian.This supports the finding of Inoceramus(Cremnoceramus)waltersdorfensis?hannovrensis?from the same interval.Anagaudryceras?is an individual ammonite finding from the Zhepure Shanbei or Zhepure Shanpo Formation,corresponding to the Santonian-Maastrichtian part of the succession.
文摘The Cyclostratigraphy study is increasingly important in the precise dating of the marine strata, especially in the Tethyan realm.Compared with the Western Tethys,the Cyclostratigraphy study on the Eastern Tethys is relatively insufficient.Cretaceous marine sediments are cropped out widely in Southern Tibet,among them the late Cretaceous in the Gongzha section of Tingri area is rather continuous and integral.
