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.

该奖项由极地方案办公室南极地质和地球物理方案提供，为一项研究罗斯海西南部地区构造发展的研究提供资金。长期以来，东南极和西南极之间的位移一直是基于全球板块电路、明显的热点运动、海底磁异常的解释、古地磁和地质原因而提出的。这种运动需要跨越南极洲的板块边界，但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南极洲东部和西部之间新生代晚期活动的边界，在那里已经发现了年轻的构造，可以在活动伸展和陆内结构之间建立连续性，通过船只进入将能够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沿恐怖裂谷东缘的断层模式和火山结构图。将使用多波束测深技术绘制海底火山裂缝和海山路线的方位图。火山排列将显示横跨恐怖裂谷的区域伸展或剪切方向以及相关地壳应力的方向。带状水深测量和单通道地震数据将被用来记录新构造断层模式和最近断层的东部界限。新构造断裂模式的描绘将表明，恐怖裂谷的东缘是否形成了一个连续的边界，以及裂谷本身是否可以与罗斯海西北部的假定走滑断裂联系在一起。该项目的海底发现将与周围火山岛和横贯北极山脉的断层运动学和应力场测定相结合。综合结果将检验这样的命题，即恐怖裂谷的东部边界构成了穿过罗斯海的主要晚新生代活动构造的界限，并且恐怖裂谷的运动学涉及与向北的右旋走滑断层相连的右旋伸展。这些结果将有助于限制西南极裂谷系统和南大洋构造之间的运动学和动力学联系，以及东南极和西南极之间的任何相关运动。在第一年，将对现有的多通道和单通道地震剖面和恐怖裂谷上的航磁数据进行合作结构分析。将查明火山喷口或裂缝以及海底的任何断层崖的位置，并将初步解释恐怖裂谷的变形年龄和运动学。第二年晚些时候，RVIB N.B.Palmer号上的一次为期一个月的巡航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。重力、磁学、地震反射和Bathy2000 3.5千赫海底剖面数据也将通过裂谷收集。在第三年，我们将使用这些多源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)完成恐怖裂谷中新构造断裂和火山构造的地图；2)解释构造模式，以得出与裂谷发展有关的运动和应力；3)将恐怖裂谷构造与横贯北极山脉的断层和线形构造进行比较，以改善对构造的年龄限制；以及4)将来自罗斯海西部的晚新生代构造解释与南大洋板块边界运动学相结合。