纪飞^1,3,,
李斐^1,,,
张峤²,
高金耀³,
郝卫峰¹,
李永东⁴,
管清胜³,
林星⁵
1. 武汉大学中国南极测绘研究中心, 武汉 430079
2. 中国地质科学院地质力学研究所, 北京 100081
3. 自然资源部第二海洋研究所, 杭州 310012
4. 中国地质大学地球物理与空间信息学院, 武汉 430074
5. 天津市地球物理勘探中心, 天津 300170

基金项目: 国家自然科学基金（41531069，41576069，41706215，41574004），国家重点研发计划（2017YFA0603104），国家海洋局海洋沉积与环境地质重点实验室开放基金（MASEG201704），中国地质调查局中国地质科学院基本科研业务"南极西罗斯海新生代岩浆与构造和冰川作用地球物理研究"联合资助


详细信息

作者简介: 纪飞, 男, 1988年生, 博士研究生, 主要从事地球物理学研究.E-mail:jifeii@163.com

通讯作者: 李斐, 男, 教授, 博导, 主要从事行星内部构造、重力场及极地大地测量等方面的教学与研究.E-mail:fli@whu.edu.cn

中图分类号: P542;P314

收稿日期:2018-08-13
修回日期:2018-12-24
上线日期:2019-03-05

Crustal density structure of the Antarctic continent from constrained 3-D gravity inversion

JI Fei^1,3,,
LI Fei^1,,,
ZHANG Qiao²,
GAO JinYao³,
HAO WeiFeng¹,
LI YongDong⁴,
GUAN QingSheng³,
LIN Xing⁵
1. Chinese Antarctic Center of Surveying and Mapping, Wuhan University, Wuhan 430079, China
2. Institute of Geomechanics, Chinese Academy of Geological Sciences, Beijing 100081, China
3. Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou 310012, China
4. Institute of Geophysics and Geomatics, China University of Geosciences, Wuhan 430074, China
5. Tianjin Center of Geophysical Prospecting, Tianjin 300170, China


More Information

Corresponding author: LI Fei,E-mail:fli@whu.edu.cn

MSC: P542;P314

--> Received Date: 13 August 2018
Revised Date: 24 December 2018
Available Online: 05 March 2019


摘要
摘要:地壳密度是表征其物质组成以及结构特征的一个基本参数，是深入理解构造演化、地球动力学等问题的重要基础.本文利用最新发布的布格重力异常数据，以现有的三维S波速度模型、地表热流以及岩石学数据作为约束条件，采用引入深度加权函数的三维重力反演算法，获取了南极大陆三维精细密度结构模型.研究结果显示，南极大陆地壳尺度范围内密度异常在-0.25~0.20 g·cm^-3之间.大致以南极横断山脉为界，受中生代与新生代多期拉张活动的影响，西南极上地壳密度异常以低值为主，与东南极克拉通的高密度异常呈现明显对比关系.通过对比发现，反演的密度结构与岩石圈强度信息存在较好的相关性.进一步分析西南极裂谷系统的密度结构与岩石圈强度，认为受新生代拉张活动和岩浆活动影响的局部地区除外，热沉降作用很可能使得地壳趋于冷却.此外，西南极的低密度特征延伸到南极横断山脉，结合现有的研究结果认为可能需要多种机制来解释南极横断山脉的隆升过程.
关键词: 南极大陆/
地壳/
三维重力反演/
密度结构/
参考密度模型

Abstract:Crustal density is a fundamental physical parameter that helps to reveal its composition and structure, and hence it is also significantly related to the tectonic evolution and geodynamics. Based on the latest complete Bouguer gravity anomalies and by the constrains of 3-D shear velocity model, surface heat flow and petrology data, the 3-D gravity inversion method, incorporating deep weighting function, has been used to obtain the refined density structure over the Antarctic continent. Our results show that the density anomalies changes from -0.25 g·cm^-3 to 0.20 g·cm^-3. Due to the multi-phase extensional tectonics in Mesozoic and Cenozoic, respectively, the low density anomalies dominates in the West Antarctica, whereas the East Antarctica is characterized by high values of density anomalies. By comparing with the variations of effective elastic thickness, the inverted density structure correlates well with the lithospheric strength. According to the mechanical strength and inverted density anomalies in the West Antarctic Rift System (WARS), our analysis find that except for the small-scale area affected by the Cenozoic extension and magmatic activity, the crustal thermal structure in the most part of WARS tends to be normal under the effect of thermal diffusion. Finally, the low density anomalies features in West Antarctica extend to beneath the Transantarcitc Mountains (TAMs), however, we hypothesize that a single rift mechanism seems not be used to explain the entire TAMs range.
Key words:Antarctic continent/
Crust/
3-D gravity inversion/
Density structure/
Reference density model



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