The exhumation of northern Victoria Land and consequences on the uplift of the Transantarctic Mountains

维多利亚北部土地的挖掘及其对横贯南极山脉隆起的影响

• 批准号: 404780998
• 负责人: Professor Dr. Frank Lisker
• 金额: --
• 依托单位: Bundesanstalt für Geowissenschaften und Rohstoffe (BGR)
• 依托单位国家: 德国
• 项目类别: Infrastructure Priority Programmes
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/404780998?language=en
• 关键词: exhumation; northern; Victoria; Land; consequences

The project aims to reconstruct the long-term landscape evolution of northern Victoria Land. The study area occupies the termination of the Transantarctic Mountains at the intersection between the Pacific Antarctic transform margin and the West Antarctic Rift System. It is composed of three terranes: the Precambrian cratonic Wilson Terrane, and the Paleozoic metasedimentary Bowers and Robertson Bay terranes. This geological division is reflected by a distinctive geomorphological contrast between elevated, deeply incised inland plateaus and an Alpine coastal morphology, and appears to correlate with considerably varying uplift and exhumation histories. Exhumation of the Wilson Terrane has been reconstructed in detail during the last years my means of thermochrono¬logical and structural data, and geomorphological observation. These data require the existence of a long-lasting Mesozoic basin in the vicinity of the present Transantarctic Mountains that was exhumed in two stages. Basin inversion and extensive denudation commenced in the Early Oligocene, followed by increased uplift, plateau formation and incision since the Miocene. The project focuses on the exhumation of the Bowers and Robertson Bay Terranes and related tectonic processes, as well as the development of the landscape contrast across northern Victoria Land. The outcome of the project will enhance substantially our knowledge about the uplift of the Transantarctic Mountains and the evolution of the West Antarctic Rift System, contribute new arguments for the interpretation of the seismic stratigraphy in the Ross Sea troughs, and improve our understanding of the system tectonics – climate – lithology. It also has first-order consequences on timing and course of Gondwana breakup between Antarctica and Australia and will provide essential background parameters for the long-term climate reconstruction of the southern hemisphere. Methodologically, the project relies on structural geology, geomorphological observation and sampling of basement, cover rocks and brittle structures during the BGR expedition GANOVEX XIII (2018/19). Subsequent thermochronological research includes fission track (FT) and (U-Th-Sm)/He analyses on apatites and zircons, followed by thermal history modelling and a three-dimensional reconstruction of the isotherm pattern of the uppermost crust.

该项目旨在重建北方维多利亚地的长期景观演变。研究区域位于太平洋-南极转换边缘和西南极裂谷系交汇处的横贯南极山脉的末端。它由三个岩块组成：前寒武纪的威尔逊地体和古生代的鲍尔斯和罗伯逊湾变质沉积岩块。这种地质划分反映了一个独特的地貌对比之间的高架，深切割的内陆高原和阿尔卑斯山沿海形态，并出现了相当不同的隆起和剥露历史。在过去的几年里，我利用热年代学和构造数据以及地貌观测对威尔逊地体的发掘进行了详细的重建。这些数据需要在目前的横贯南极山脉附近存在一个长期的中生代盆地，该盆地分两个阶段被挖掘出来。早渐新世开始盆地反转和大规模剥蚀，中新世以来逐渐隆升、高原形成和下切。该项目的重点是鲍尔斯和罗伯逊湾地体的发掘和相关的构造过程，以及北方维多利亚地景观对比的发展。该项目的成果将大大提高我们对南极洲横贯山脉隆升和西南极裂谷系演化的认识，为罗斯海槽地震地层学的解释提供新的论据，并提高我们对该系统构造-气候-岩性的理解。它还对南极洲和澳大利亚之间冈瓦纳大陆分裂的时间和过程产生了一级影响，并将为南半球的长期气候重建提供重要的背景参数。在方法上，该项目依赖于BGR考察GANOVEX XIII（2018/19）期间的构造地质学，地貌观测以及基底，盖层岩石和脆性结构的采样。随后的热年代学研究包括裂变径迹（FT）和（U-Th-Sm）/He分析磷灰石和锆石，其次是热历史建模和三维重建的等温线模式的最上层地壳。