Geochronology and Mammalian Paleobiogeography of the Ghazij Formation, Pakistan: Implications for the Indian-Asian Collision and the Paleocene-Eocene Boundary

巴基斯坦加济杰地层的年代学和哺乳动物古生物地理学：对印度-亚洲碰撞和古新世-始新世边界的影响

基本信息

批准号：
9902905
负责人：
William Clyde
金额：
$ 14.56万
依托单位：
University of New Hampshire
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
1999
资助国家：
美国
起止时间：
1999-09-01 至 2004-08-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=9902905&HistoricalAwards=false
关键词：
Geochronology Mammalian Paleobiogeography Ghazij Formation

项目摘要

Recent discovery of fossil terrestrial mammals in the relatively undeformed paralic and continental sediments of the lower Eocene Ghazij Formation, Baluchistan Province, Pakistan provides a unique opportunity to investigate the paleogeography and paleobiogeography of the critical region between Indo-Pakistan and Asia before final suturing. This award supports an investigation of the geochronology, paleogeography, and paleobiogeography of the Ghazij Formation in order to test the hypothesis that the "modern" orders of mammals (primates, artiodactyls, and perissodactyls) originated on the Indo-Pakistan continent before collision and dispersed across the holarctic after collision. The geochronology of the Ghazij will be evaluated using magnetostratigraphy since there are no known isotopically dateable horizons and preliminary paleomagnetic results suggest that many Ghazij facies are conducive to this methodology. Paleogeography will be reconstructed using sandstone paleocurrent and provenance analysis in order to evaluate the location and composition of the source region for the fluvial sediments in the middle and upper Ghazij Formation. Ghazij paleobiogeography will be evaluated by continued sampling of vertebrate faunas and comparison of these assemblages to similarly aged vertebrate faunas from Asia, Europe, and North America. The coarse conglomerates and continental facies of the upper Ghazij Formation may represent the sedimentary response to initial Indo-Asian collisional deformation and thus could help resolve ongoing debates related to the timing and geometry of this important tectonic event.

最近在巴基斯坦俾路支省始新世Ghazij组下游相对未变形的陆生和大陆沉积物中发现了陆地哺乳动物化石，这为研究印巴和亚洲之间关键区域在最终缝合之前的古地理和古生物地理提供了独特的机会。该奖项支持对加济杰地层的地质年代学、古地理学和古生物地理学进行调查，以检验“现代”哺乳动物目（灵长类、偶蹄类和奇蹄类）在碰撞和分散之前起源于印巴大陆的假设碰撞后穿越整个北冰洋。加济杰的地质年代学将使用磁地层学进行评估，因为没有已知的同位素测年层位，并且初步的古地磁结果表明许多加济杰相有利于这种方法。将利用砂岩古水流和物源分析重建古地理，以评估中上部加济杰组河流沉积物源区的位置和组成。加齐季古生物地理学将通过对脊椎动物群进行持续采样并将这些组合与来自亚洲、欧洲和北美的类似年龄的脊椎动物群进行比较来评估。加济杰组上部的粗砾岩和大陆相可能代表了对最初印度-亚洲碰撞变形的沉积响应，因此有助于解决与这一重要构造事件的时间和几何形状有关的持续争论。