Cretaceous-Paleogene Foraminiferida of the Victoria Land Basin (Cape Roberts Project)

维多利亚陆盆地白垩纪-古近纪有孔虫（罗伯茨角项目）

• 批准号: 9420475
• 负责人: Peter-Noel Webb
• 金额: $ 12.47万
• 依托单位: Ohio State University Research Foundation -DO NOT USE
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-06-15 至 2002-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9420475&HistoricalAwards=false
• 关键词: Cretaceous; Paleogene; Foraminiferida; Victoria; Land

Abstract This award supports efforts to characterize the foraminifera in drill core recovered by the Cape Roberts Project (CRP). The CRP will drill four holes, from a sea-ice platform in up to 500m of water, in the southwest Ross Sea. Geophysical site surveys suggest that the four drill holes will provide an aggregate thickness of about 1500m of core and span about 100 to about 30 Ma (Cretaceous-Paleocene). This interval of geological time is not yet documented by in situ stratigraphic sections in either the Ross Sea or East Antarctica. The nearest comprehensive data sources for the Cretaceous and Paleocene) occur in New Zealand, the northern Antarctic Peninsula and the southern ocean. Benthic and planktic Foraminiferida from the core will be used, together with data from other fossil groups, to provide on-site age and stratigraphic control as drilling progresses. Age correlations will be made with DSDP/ODP biostratigraphy from southern Ocean drill sites, and also with New Zealand planktic and benthic zonal/stage schemes. A principal task of this work is to document in the project's initial report, a comprehensive accounting of foraminiferal material present so as to assist planning of post-drilling investigations. Basic information to be recorded on the foraminifera will include: presence, abundance, preservation, species dominance and diversity, stratigraphic distribution, levels of endemism or cosmopolitanism in faunas, and completeness or fragmentation of population structures, et cetera. These data will be used to address a variety of geological problems. Disconformities and acoustic reflectors which extend across the rift system basins and are also expected to be encountered in the drill hole will be dated. Major basin subsidence/uplift trends resulting from compaction and/or rift margin faulting will be deduced from benthic foraminiferal bathymetric indicators. More subtle cyclicity in the stratigraphic distribution of benthic species will be u sed to recognize and document phases of transgression and regression, which in turn may indicate a relationship between sea level oscillation and terrestrial glacial events. The Cretaceous- Paleocene was an interval of time during which the final disintegration of Gondwanaland occurred, specifically the northward movement of New Zealand and Australia away from Antarctica. Foraminifera from the CRP drill holes will contribute to an understanding of the paleogeography and paleoceanography between the highlands and Pacific margin of East Antarctica (the location of the proto-Transantarctic Mountains), and the West Antarctic Rift System basins between this suspected island chain and the highlands of West Antarctica. This will help answer the question as to whether the marine margin of East Antarctica, in the vicinity of the planned drill holes, was located in a Cretaceous cul-de-sac, or whether it occupied, at times, a position on a major oceanic circulation pathway between the SW Indian Ocean, SW Pacific, and SW Atlantic Oceans.

该奖项支持对罗伯茨角项目(CRP)发现的钻芯中的有孔虫进行表征的努力。CRP将在罗斯海西南部的海冰平台上钻四个洞，深度可达500米。地球物理现场勘测表明，这四个钻孔将提供约1500米的岩心总厚度，跨度约为100至约30 Ma(白垩纪-古新世)。罗斯海或东南极洲的原位地层切片还没有记录下这段地质时间。最近的白垩纪和古新世综合数据来源)位于新西兰、南极半岛北部和南大洋。将使用来自岩心的海底和浮游有孔虫，以及来自其他化石组的数据，随着钻探的进行提供现场年龄和地层控制。将与南大洋钻探现场的DSDP/ODP型生物地层学以及新西兰的浮游带和底栖带/阶段方案进行年龄对比。这项工作的一项主要任务是在项目的初步报告中记录对现有有孔虫材料的全面核算，以协助规划钻探后的调查。将记录在有孔虫上的基本信息将包括：存在、丰度、保存、物种优势度和多样性、地层分布、动物群中特有或世界性的程度，以及种群结构的完整性或碎片化等。这些数据将用于解决各种地质问题。延伸到裂谷系统盆地的不整合和声波反射层预计也将在钻孔中遇到，这些不整合和声波反射层将被确定日期。由压实作用和/或裂谷边缘断层作用引起的主要盆地沉陷/抬升趋势将从海底有孔虫测深指标推断出来。海底物种地层分布的更微妙的旋回性将被用来识别和记录海侵和退缩的阶段，这反过来可能表明海平面波动和陆地冰川事件之间的关系。白垩纪-古新世是冈瓦瓦兰发生最终解体的一段时间，特别是新西兰和澳大利亚向北远离南极洲。来自CRP钻孔的有孔虫将有助于了解东南极高地和太平洋边缘(原横贯北极山脉的位置)之间的古地理和古海洋，以及这一疑似岛链和西南极高地之间的西南极裂谷系盆地。这将有助于回答这样一个问题，即计划中的钻孔附近的东南极海缘是否位于白垩纪的死胡同，或者它是否有时占据了西南印度洋、西南太平洋和西南大西洋之间的主要海洋环流通道的位置。