Collaborative Research: Neotectonic Structure of Terror Rift, Western Ross Sea

合作研究：西罗斯海恐怖裂谷的新构造结构

• 批准号: 0125624
• 负责人: Terry Wilson
• 金额: --
• 依托单位: Ohio State University Research Foundation -DO NOT USE
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-07-01 至 2008-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0125624&HistoricalAwards=false
• 关键词: Collaborative; Research; Neotectonic; Structure; Terror

This award, provided by the Antarctic Geology and Geophysics Program of the Office of Polar Programs, provides funds for a study to investigate the tectonic development of the southwestern Ross Sea region. Displacements between East and West Antarctica have long been proposed based on global plate circuits, apparent hot spot motions, interpretations of seafloor magnetic anomalies, paleomagnetism, and on geologic grounds. Such motions require plate boundaries crossing Antarctica, yet these boundaries have never been explicitly defined. This project will attempt to delineate the late Cenozoic - active boundary between East and West Antarctica along the Terror Rift in the western Ross Sea, where young structures have been identified, continuity between active extension and intracontinental structures can be established, and where accessibility via ship will allow new key data sets to be acquired. We will use multi-source marine and airborne geophysical data to map the fault patterns and volcanic structure along the eastern margin of the Terror Rift. The orientations of volcanic fissures and seamount alignments on the seafloor will be mapped using multibeam bathymetry. The volcanic alignments will show the regional extension or shear directions across the Terror Rift and the orientations of associated crustal stresses. Swath bathymetry and single channel seismic data will be used to document neotectonic fault patterns and the eastern limit of recent faulting. Delineation of neotectonic fault patterns will demonstrate whether the eastern margin of the Terror Rift forms a continuous boundary and whether the rift itself can be linked with postulated strike-slip faults in the northwestern Ross Sea. Seafloor findings from this project will be combined with fault kinematic and stress field determinations from the surrounding volcanic islands and the Transantarctic Mountains. The integrated results will test the propositions that the eastern boundary of the Terror Rift forms the limit of the major, late Cenozoic -active structures through the Ross Sea and that Terror Rift kinematics involve dextral transtension linked to the right-lateral strike-slip faulting to the north. These results will help constrain the kinematic and dynamic links between the West Antarctic rift system and Southern Ocean structures and any related motions between East and West Antarctica. In the first year, a collaborative structural analysis of existing multichannel and single channel seismic profiles and aeromagnetic data over the Terror Rift will be conducted. The location of volcanic vents or fissures and any fault scarps on the sea floor will be identified and a preliminary interpretation of the age and kinematics of deformation in the Terror Rift will be produced. Late in the second year, a one-month cruise on RVIB N.B. Palmer will carry out multibeam bathymetric and sidescan sonar mapping of selected portions of the seafloor of Terror Rift. Gravity, magnetics, seismic reflection and Bathy2000 3.5 kHz sub-bottom profile data will also be collected across the rift. In the third year, we will use these multisource data to map the orientations and forms of volcanic bodies and the extent and geometry of neotectonic faulting associated with the Terror Rift. The project will: 1) complete a map of neotectonic faults and volcanic structures in the Terror Rift; 2) interpret the structural pattern to derive the motions and stresses associated with development of the rift; 3) compare Terror Rift structures with faults and lineaments mapped in the Transantarctic Mountains to improve age constraints on the structures; and 4) integrate the late Cenozoic structural interpretations from the western Ross Sea with Southern Ocean plate boundary kinematics.

该奖项由极地计划办公室南极地质和地球物理计划提供，为调查罗斯海西南部地区构造发展的研究提供资金。东、西南极洲之间的位移长期以来一直是根据全球板块回路、明显的热点运动、海底磁异常的解释、古地磁学和地质学基础提出的。这样的运动需要跨越南极洲的板块边界，然而这些边界从未被明确定义过。该项目将试图沿着罗斯海西部的恐怖裂谷划定东南极洲和西南极洲之间的晚新生代活动边界，在那里已经确定了年轻的构造，可以确定活动伸展和陆内构造之间的连续性，通过船舶可以获得新的关键数据集。我们将使用多源海洋和航空地球物理数据来绘制恐怖裂谷东部边缘沿着的断层模式和火山结构。将使用多波束测深法绘制海底火山裂缝和海山走向图。火山排列将显示恐怖裂谷的区域延伸或剪切方向以及相关地壳应力的方向。条带测深和单道地震数据将用于记录新构造断层模式和现代断层的东部界限。新构造断层模式的描绘将证明恐怖裂谷的东缘是否形成一个连续的边界，以及裂谷本身是否可以与假定的罗斯海西北部的走滑断层相连。该项目的海底调查结果将与从周围火山岛和横贯南极山脉确定的断层运动学和应力场相结合。综合的结果将测试的命题，恐怖裂谷的东部边界形成的限制，主要的，晚新生代活跃的结构通过罗斯海和恐怖裂谷运动学涉及右旋transtension链接到右侧走滑断层向北。这些结果将有助于限制西南极裂谷系统和南大洋结构之间的运动学和动力学联系以及东南极洲和西南极洲之间的任何相关运动。 在第一年，将对恐怖裂谷现有的多通道和单通道地震剖面图以及航空磁力数据进行协作结构分析。将查明海底火山口或裂缝以及任何断层陡坎的位置，并对恐怖裂谷的变形年代和运动学作出初步解释。第二年年底，在RVIB N.B.上进行为期一个月的巡航。帕尔默将对恐怖裂谷海底的选定部分进行多波束测深和侧扫声纳测绘。还将在整个裂谷收集重力、磁力、地震反射和Bathy 2000 3.5 kHz海底下剖面数据。在第三年，我们将使用这些多光谱数据来绘制火山体的方向和形式以及与恐怖裂谷相关的新构造断层的范围和几何形状。该项目将：1）完成恐怖裂谷的新构造断层和火山构造图; 2）解释构造模式以导出与裂谷发展相关的运动和应力; 3）将恐怖裂谷构造与横贯南极山脉中绘制的断层和线性构造进行比较，以改进对构造的年龄限制;（4）将罗斯海西部晚新生代构造解释与南大洋板块边界运动学结合起来。