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Stratigraphy and fossil fauna of the marine Triassic System in Russian Far East

俄罗斯远东海相三叠系地层学和化石动物群

基本信息

批准号：
17540447
负责人：
SHIGETA Yasunari
金额：
$ 2.35万
依托单位：
National Museum of Nature and Science, Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2007
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-17540447/
关键词：
Triassic Russian Far East stratigraphy biodiversity extinction recovery ammonite nautiloid 年代層序絶滅と回復二枚貝

项目摘要

The stratigraphy and paleontology of the Lower Triassic in South Primorye, Russia were thoroughly investigated in 2005, 2006 and 2007. The Lower Triassic is divided into the Lazurnaya and Zhitkov formations in ascending order. The Lazurnaya Formation unconformably covers the Permian rocks, and consists of basal conglomerate and shallow marine sandstones with hummocky cross stratification. The Zhitkov Formation is composed mainly of offshore black mudstone with slump deposit and turbiditic sandstone. Ammonites are abundant throughout the sequence, in which several ammonite zones were recognized successively from upper Lower Induan(Upper Griesbachian) to upper Lower Olenekian(Upper Smithian). The Induan ammonites include several species in common with South China and Canada, but the most Lower Olenekian ammonites are endemic species. This fact suggests that ammonites diversified regionally during the early Olenekian. Five species belonging to four genera of nautiloids were discovered from the Induan. They show a various shell form from involute, evolute and gyroconic coiling, and various siphuncle position from center to ventral. They belong to the same family, and it is very likely that they rapidly diversified from single ancestor survived at P/T extinction event during the early Triassic. The nautiloid diversity was the highest in the South Primorye. This fact suggests that the recovery of the nautiloid in South Primorye was much faster than the other area.

2005年、2006年和2007年对俄罗斯南滨海地区下三叠统地层学和古生物学进行了深入研究。下三叠统按升序划分为Lazurnaya组和Zitkov组。Lazurnaya组不整合地覆盖二叠系岩石，由底部砾岩和丘状交错层理的浅海相砂岩组成。日特科夫组主要由近海黑色泥岩、滑塌沉积和浊积砂岩组成。在整个层序中都含有丰富的菊石，其中从上下印度河(上格里斯巴赫统)到上下奥伦基统(上史密斯统)先后识别出几个菊石带。印度河菊石包括几个与南中国和加拿大相同的物种，但最下奥伦基期的菊石是特有物种。这一事实表明，菊石在奥莱基期早期具有区域多样性。在印度河流域发现鹦鹉螺目4属5种。它们呈现出从渐开线、渐开线和回转锥形盘绕的不同壳形，以及从中心到腹面的不同虹吸位置。它们属于同一科，很可能是从早三叠世P/T灭绝事件中幸存下来的单一祖先迅速分化而来的。鹦鹉螺体多样性在南滨海最高。这一事实表明，南滨海地区鹦鹉螺体的恢复速度比其他地区快得多。