Air-Ground Study of Tectonics at the Boundary Between the Eastern Ross Embayment and Western Marie Byrd Land, Antarctica: Basement Geology and Structure

南极洲东罗斯湾和西玛丽伯德地边界的空地构造研究：基底地质和结构

• 批准号: 9615282
• 负责人: Christine Siddoway
• 金额: $ 11.5万
• 依托单位: Colorado College
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-08-15 至 2003-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9615282&HistoricalAwards=false
• 关键词: Air; Ground; Study; Tectonics; Boundary

OPP 9615281 Luyendyk OPP 9615282 Siddoway Abstract This award supports a collaborative project that combines air and ground geological-geophysical investigations to understand the tectonic and geological development of the boundary between the Ross Sea Rift and the Marie Byrd Land (MBL) volcanic province. The project will determine the Cenozoic tectonic history of the region and whether Neogene structures that localized outlet glacier flow developed within the context of Cenozoic rifting on the eastern Ross Embayment margin, or within the volcanic province in MBL. The geological structure at the boundary between the Ross Embayment and western MBL may be a result of: 1) Cenozoic extension on the eastern shoulder of the Ross Sea rift; 2) uplift and crustal extension related to Neogene mantle plume activity in western MBL; or a combination of the two. Faulting and volcanism, mountain uplift, and glacier downcutting appear to now be active in western MBL, where generally East-to-West-flowing outlet glaciers incise Paleozoic and Mesozoic bedrock, and deglaciated summits indicate a previous North-South glacial flow direction. This study requires data collection using SOAR (Support Office for Aerogeophysical Research, a facility supported by Office of Polar Programs which utilizes high precision differential GPS to support a laser altimeter, ice-penetrating radar, a towed proton magnetometer, and a Bell BGM-3 gravimeter). This survey requires data for 37,000 square kilometers using 5.3 kilometer line spacing with 15.6 kilometer tie lines, and 86,000 square kilometers using a grid of 10.6 by 10.6 kilometer spacing. Data will be acquired over several key features in the region including, among other, the eastern edge of the Ross Sea rift, over ice stream OEO, the transition from the Edward VII Peninsula plateau to the Ford Ranges, the continuation to the east of a gravity high known from previous reconnaissance mapping over the Fosdick Metamorphic Complex, an d the extent of the high-amplitude magnetic anomalies (volcanic centers?) detected southeast of the northern Ford Ranges by other investigators. SOAR products will include glaciology data useful for studying driving stresses, glacial flow and mass balance in the West Antarctic Ice Sheet (WAIS). The ground program is centered on the southern Ford Ranges. Geologic field mapping will focus on small scale brittle structures for regional kinematic interpretation, on glaciated surfaces and deposits, and on datable volcanic rocks for geochronologic control. The relative significance of fault and joint sets, the timing relationships between them, and the probable context of their formation will also be determined. Exposure ages will be determined for erosion surfaces and moraines. Interpretation of potential field data will be aided by on ground sampling for magnetic properties and density as well as ground based gravity measurements. Oriented samples will be taken for paleomagnetic studies. Combined airborne and ground investigations will obtain basic data for describing the geology and structure at the eastern boundary of the Ross Embayment both in outcrop and ice covered areas, and may be used to distinguish between Ross Sea rift- related structural activity from uplift and faulting on the perimeter of the MBL dome and volcanic province. Outcrop geology and structure will be extrapolated with the aerogeophysical data to infer the geology that resides beneath the WAIS. The new knowledge of Neogene tectonics in western MBL will contribute to a comprehensive model for the Cenozoic Ross rift and to understanding of the extent of plume activity in MBL. Both are important for determining the influence of Neogene tectonics on the ice streams and WAIS.

OPP 9615281 LUYENDYK OPP 9615282 SIDDOWAY摘要该奖项支持一个合作项目，该项目结合了空气和地面地质地球物理学研究，以了解Ross Sea Rift和Marie Byrd Land（MBL Land（MBL）Volcanic Province之间边界的构造和地质发展。 该项目将确定该地区的Cenozoic构造历史，以及在东部罗斯胚胎边缘的新生代裂谷中开发的定位出口冰川流量的新金元结构是在MBL中开发的。 Ross Embayment和Western MBL之间边界的地质结构可能是：1）在罗斯海裂谷东部肩膀上的新生代延伸； 2）与西部MBL的新金元地幔活性有关的隆起和地壳延伸；或两者的组合。 断层和火山，山地隆起和冰川下降似乎现在活跃在MBL的西部，那里通常是向东到西部流动的出口冰川开裂古生代和中生代基岩，而脱胶式山顶表明先前的南北露出流动方向。 这项研究需要使用SOAR收集数据（航空物理研究的支持办公室，这是由极地计划办公室支持的设施，该设施利用高精度差异GPS支持激光高度计，冰渗透雷达，牵引质子磁力计和Bell BGM-3重量表）。 这项调查需要使用5.3公里的线间距，并使用15.6公里的领带线进行37,000平方公里的数据，并使用10.6 x 10.6公里的间距的网格进行86,000平方公里。 该数据将在该地区的几个关键特征上获取，包括罗斯海裂谷的东部边缘，越过冰流OEO，从爱德华VII半岛高原到福特范围的过渡，延续的重力向以前的重力延伸，从先前的侦察中绘制了fosdick Metamorphic Complecter的范围范围的范围？其他调查员在北福特北部的东南部。 SOAR产品将包括用于研究驱动应力，冰川流量和质量平衡（WAIS）的冰川数据。 地面计划以南部福特范围为中心。 地质场映射将集中在小规模的脆性结构上，用于区域运动学解释，冰川表面和沉积物，以及用于地球文学控制的数据岩石。 断层和关节集的相对意义，它们之间的时机关系以及其形成的可能上下文也将得到确定。 暴露年龄将确定针对侵蚀表面和moraines。 通过对磁性和密度的地面采样以及基于地面的重力测量，可以帮助电场数据的解释。 面向的样品将用于古磁研究。 合并的空降和地面调查将获得基本数据，以描述露头和冰覆盖区域的罗斯胚胎东部边界的地质和结构，并可用于区分罗斯海裂谷相关的结构活动与MBL圆顶和Volcanic Province的外围的Ross Sea Rift相关的结构活动。 露头地质和结构将用空气地球物理数据推断出来，以推断出在WAIS下方的地质。 西方MBL中新金元构造学的新知识将有助于综合的新生代罗斯裂谷，并了解MBL中羽流活动的程度。 两者对于确定新金元构造对冰流和WAIS的影响很重要。