East Antarctic glacial history through microfossil analyses of the Pagodroma Group

通过对帕戈德罗马群的微化石分析了解南极东部冰川历史

• 批准号: 0089899
• 负责人: David Harwood
• 金额: $ 6.56万
• 依托单位: University of Nebraska-Lincoln
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-03-15 至 2002-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0089899&HistoricalAwards=false
• 关键词: East; Antarctic; glacial; history; through

0089899HarwoodThis award, provided by the Antarctic Geology and Geophysics Program of the Office of Polar Programs, supports a micropaleontological investigation of Pagodroma Group sediments to complement and enhance prior stratigraphic and paleoenvironmental studies of these Cenozoic glacial deposits of East Antarctica. Preliminary results indicate the presence of Oligocene (?), middle Miocene, upper Miocene and Pliocene-Pleistocene glaciomarine strata that have the potential to contribute significantly to our understanding of the past fluctuations in the extent and character of the East Antarctic Ice Sheet (EAIS). These strata were deposited in a glacial system involving EAIS drainage through the Lambert Glacier and repeated marine incursion and ice margin/grounding line retreat across a distance of more than 800 km. Paleontological and sedimentological information present within these strata have the potential to provide baseline climate information bearing on the history of the EAIS. The Pagodroma Group sequences will provide a Neogene record of glaciomarine deposition on the continental interior that will expand what is already known from drill cores and outcrops in the Dry Valley region and the Vestfold Hills. These deposits are dated biostratigraphically by the occurrence of in situ diatom and foraminifera assemblages that occur in laterally-continuous beds of diatomaceous marine mudstone within a sequence of diamictite. These fossils provide direct age correlation to Southern Ocean and Ross Sea biostratigraphic schemes. Open marine diatom production and in situ diatom sedimentation is noted in several deposits of the Pagodroma Group that are at least 300 km inland from the current coastline. This new research will focus on establishing the age of different deposits of the Pagodroma Group through the study of in situ and glacially reworked microfossil assemblages. This will aid in the reconstruction of a composite history of the EAIS-Lambert Glacier-Amery Basin-Prydz Bay system. Primary objectives of this proposal are: (1) to develop a temporal and spatial record of Neogene EAIS variability, and (2) to test hypotheses that predict future changes in the EAIS in response to elevated global temperatures with geologic data. In addition, biostratigraphical and paleoecological analyses can reveal sea-surface temperature, sea level and sea-ice conditions, among other environmental parameters at the time of deposition. The ability to date and interpret these paleoenvironmental conditions is improving steadily through continued study of Cenozoic Antarctic diatom-bearing deposits, yet much remains to be done. Analyses will be undertaken on 250 Pagodroma Group samples collected during the 1997/98 field season. Currently 116 samples are available from deposits on the Amery Oasis, which is 250 km inland from the modern coast; 5 samples from Mt Stinear, 500 km inland; and 84 samples from Mt Menzies, which is 600 km inland. The bulk of this project will be conducted by a post-doctoral scientist, who will continue to improve the biostratigraphic and paleoecological use of diatoms and further extend his education and experience in Cenozoic Antarctic diatom paleontology. Future stratigraphic drilling programs that are planned for the Antarctic shelf and margin by numerous international Antarctic programs will require the skills of several experienced diatom paleontologists to provide age and environmental control for recovered materials. In summary, this project will provide further experience and training for a postdoctoral researcher on important materials that will help to answer current questions about Neogene variability of the East Antarctic Ice Sheet and the likely response to elevated global temperatures in the future.

0089899HARWOODIS这项奖项由《极地计划办公室的南极地质与地球物理学计划》提供，支持对Pagodroma集团沉积物进行的微生态内生物学研究，以补充和增强这些乔纳斯葡萄质沉积物的先前地层和古环境研究。初步结果表明，存在渐新世（？），中新世中期，上新世和上新世 - 丙酸冰川层层，这些地层具有显着贡献我们对过去南极冰盖（EAIS）（EAIS）范围和特征的过去波动的理解。这些地层沉积在冰川系统中，该系统涉及通过兰伯特冰川引流的EAIS排水，并反复出现海洋入侵，并在超过800公里的距离上撤退了冰缘/接地线。这些层中存在的古生物学和沉积学信息有可能提供有关EAIS历史的基线气候信息。 Pagodroma组序列将在大陆内部提供冰川膜沉积的新金素记录，该记录将扩大干谷地区和Vestfold山丘中已经知道的钻头和露头已知的内容。这些沉积物是通过在硅藻土海洋泥岩的侧面连续床中发生的原位硅藻和有孔虫的组合来进行生物地层的。这些化石提供了与南大洋和罗斯海生物地层学方案的直接年龄相关性。在距目前海岸线至少300公里的pagodroma组的几个沉积物中，有开放的海洋硅藻产生和原位硅藻沉积物在帕戈多马瘤组的几个沉积物中注意到。这项新的研究将着重于通过对原位和冰川重制的微化石组合的研究来建立Pagodroma群体不同沉积物的年龄。这将有助于重建Eais-Lambert冰川盆地盆地湾系统的复合历史。该提案的主要目标是：（1）开发新金元EAIS可变性的时间和空间记录，以及（2）测试假设，以预测EAIS未来变化，以响应使用地质数据升高的全球温度升高。此外，在沉积时，生物地层学和古生态分析可以揭示海面温度，海平面和海冰条件以及其他环境参数。通过继续研究新生代南极含硅藻的沉积物，约会和解释这些古环境条件的能力正在稳步改善，但仍有很多事情要做。分析将对1997/98野外季节期间收集的250个Pagodroma组样本进行。目前，有116个样品可从俄亥俄州的俄亥俄州的矿床上找到，距离现代海岸250公里； 5个样品来自山山，内陆500公里；以及内陆600公里的MT Menzies的84个样品。该项目的大部分将由博士后科学家进行，他们将继续改善硅藻的生物地层学和古生态学用途，并进一步扩大他在新生代南极硅藻科学方面的教育和经验。为南极货架计划的未来地层钻探计划和许多国际南极计划的利润率将要求几位经验丰富的硅藻科学家的技能，以为恢复的材料提供年龄和环境控制。总而言之，该项目将为博士后研究人员提供进一步的经验和培训，这些研究人员将有助于回答有关东南极冰盖新近金属变异性的当前问题，并可能对未来全球温度升高的反应。