Collaborative Research: Recovery of Vertebrate Faunas after the K/T Boundary, Tullock Formation, Eastern Montana

合作研究：蒙大拿州东部塔洛克地层 K/T 边界后脊椎动物群的恢复

• 批准号: 9505841
• 负责人: William Clemens
• 金额: $ 7.1万
• 依托单位: University of California-Berkeley
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-07-15 至 1997-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9505841&HistoricalAwards=false
• 关键词: Collaborative; Research; Recovery; Vertebrate; Faunas

Clemens 9505841 The first objective of the project will be to refine the stratigraphic correlations of over 100 Early Paleocene vertebrate fossil localities in eastern Montana already discovered and sampled. Here widespread coal/lignite beds bracketing many fossil localities contain interbeds of sanidine-bearing bentonites excellent for 40Ar/39Ar dating with a potential resolution of 0.1%. Preliminary studies using criteria described by Swisher et al. (1993) indicate that high resolution 40Ar/39Ar age determinations, in conjunction with microprobe analysis of interbedded volcanics and detailed magnetostratigraphies, are capable of providing precise identifications of individual coal/lignite beds throughout the area. The resulting chronology will provide the basis for testing hypotheses of correlation of Early Paleocene local faunas from Montana with those known from New Mexico, Alberta, and intervening areas. Interpretations of the processes and rates of biotic recovery after mass extinctions involve competing hypotheses concerning the relative significance of local survival, cladogenic diversification, and immigration from refuge areas. Our preliminary results show the Early Paleocene, Puercan North American Land Mammal Age (NALMA), as recognized in eastern Montana, had a duration of ca. 1 Ma. Puercan and early Torrejonian NALMA (Middle Paleocene) local faunas can be ordered in at least four temporal units. Analysis of the systematic relationships of the mammals and other vertebrates in these stratigraphically well-controlled local faunas will provide the basis for much more refined tests of hypotheses concerning the evolutionary processes operative during the recovery of the terrestrial biota after the Cretaceous mass extinction than previously possible. Locality and systematic data will continue to be recorded in computer-based curatorial systems at the University of California Museum of Paleontology and will be readily available to the research community.

克莱门斯9505841 该项目的第一个目标将是完善在蒙大拿州东部已经发现和取样的100多个早古新世脊椎动物化石地点的地层对比。 在这里，广泛分布的煤/褐煤层包围着许多化石地点，其中含有含透长石的辉长岩夹层，非常适合40 Ar/39 Ar测年，潜在分辨率为0.1%。 使用Swisher等人（1993年）描述的标准进行的初步研究表明，高分辨率40 Ar/39 Ar年龄测定，结合层间火山岩的微探针分析和详细的磁性地层学，能够提供整个地区单个煤/褐煤层的精确识别。 由此产生的年表将提供测试假设的相关性的早期古新世当地动物群从蒙大拿州与那些已知的从新墨西哥州，阿尔伯塔，和干预地区的基础。 大规模灭绝后生物恢复的过程和速度的解释涉及竞争的假设，当地生存的相对意义，分支多样化，从避难区移民。 我们的初步结果表明，早古新世，Puercan北美陆地哺乳动物时代（NALM），在蒙大拿州东部的认可，有一个持续时间约。1 Ma. 普尔坎和托雷琼阶早期的NALMA（中古新世）当地动物群至少可以在四个时间单位中排序。 在这些地层控制良好的当地动物群的哺乳动物和其他脊椎动物的系统关系的分析，将提供更精细的测试的假设有关的进化过程中操作的恢复白垩纪大灭绝后的陆地生物群比以前可能的基础。 地点和系统数据将继续记录在加州大学古生物博物馆的计算机管理系统中，并随时提供给研究界。