Paleogene Strata, Seymour Island, Antarctic Peninsula

摘要本奖项支持一个地质研究项目，该项目将有机会参加阿根廷南极研究所1994-95年地质实地计划。参加活动将有机会解决西摩岛古近系地层关系和年代测定中的重要问题，并实地检查美国地质勘探局正在编制的新的1:20 000地形图。西摩岛的沉积地层是南极洲唯一暴露的上白垩纪至下第三纪海相层序的一部分。白垩纪-第三纪序列沉积于与南极半岛中中生代至中新生代活动板块边缘发育有关的隐生弧后盆地。西摩岛地层的年龄介于晚坎帕尼亚和中（?）始新世至最早（?）渐新世。这些固结不良的沉积岩包含了多种多样且保存完好的无脊椎动物群、多种多样的微生物群和多种多样的脊椎动物，包括有袋动物。野外工作（将由阿根廷南极研究所在1994-95年度提供支助）的方向将是：解决西摩岛上古近系单元的复杂地层关系；收集凝灰岩层进行放射性定年、岩石学和地球化学分析；古近系演替序列分析。该奖金用于资助前往布宜诺斯艾利斯参加阿根廷南极研究所的地质项目，前往美国地质勘探局就地形图的实地检查结果进行磋商，并对实地季节收集的样本进行实验室研究。具体来说，实验室的目标是：1)确定灰层的年代，以便为缺乏钙质和硅质微化石组合的序列提供绝对的年龄控制；2)建立灰层地球化学特征，评价源区同期火山活动和岩浆演化。研究结果将为正在进行的古近系地层研究提供地层框架、支持古生物年龄和层序分析的辐射测量数据以及沉积物源区岩浆活动特征。

9508089 Elliot Abstract This award supports a geologic research project that will take advantage of an opportunity to participate in the 1994-95 geology field program of the Argentine Antarctic Institute. Participation will provide the opportunity to address important problems in the stratigraphic relations and dating of the Paleogene strata on Seymour Island and to field check the new 1:20,000 topographic map that is being prepared by the USGS. The sedimentary strata on Seymour Island are part of the only exposed Upper Cretaceous to Lower Tertiary marine sequence in Antarctica. The Cretaceous-Tertiary succession was deposited in an ensialic back-arc basin related to the development of the mid-Mesozoic to mid-Cenozoic active plate margin of the Antarctic Peninsula. Seymour Island strata range in age between Late Campanian and middle(?) Eocene to earliest(?) Oligocene. These poorly consolidated sedimentary rocks contain a diverse and exceptionally preserved invertebrate fauna, a diverse microflora, and a variety of vertebrates, including marsupials. Fieldwork (to be supported by the Argentine Antarctic Institute in the 1994-95 season) will be directed toward: resolving the complex stratigraphic relations of the Paleogene units on Seymour Island; collection of tuff beds for radiometric dating, and petrologic and geochemical analysis; and sequence analysis of the Paleogene succession. This award is to support travel to Buenos Aires to join the Argentine Antarctic Institute's geology project, travel to confer with the USGS about the results of field checking of the topographic map, and laboratory studies on samples collected in the course of the field season. Specifically, the lab objectives are to: 1) date the ash beds in order to provide absolute age control for sequences that lack calcareous and siliceous microfossil assemblages; and 2) establish the geochemistry of the ash beds to assess contemporaneous volcanic activity and magmatic evol ution of the source region. The results will provide the stratigraphic framework for on-going paleontological projects on Paleogene strata, radiometric data in support of paleontological ages and sequence analysis, and characteristics of the magmatic activity in the source region of the sediments.