Break-up of Gondwana and opening of the South Atlantic: Review of existing plate tectonic models
Break-up of Gondwana and opening of the South Atlantic: Review of existing plate tectonic models
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冈瓦纳大陆的分裂和南大西洋的开放：现有板块构造模型的回顾
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发表时间：
2007
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通讯作者：
L. Gahagan
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作者：
M. Ghidella;L. Lawver;L. Gahagan
威德尔海和南大西洋的开放历史对于理解冈瓦纳大陆的解体和早侏罗纪以来南极洲的演化至关重要。冈瓦纳纪碎片的分散对于了解过去海洋环流的发展是很重要的。不幸的是，威德尔海地区的构造是很难解决的，因为缺乏数据覆盖面和该地区的内在复杂性。虽然在过去20年中，在新的海洋航磁数据和卫星重力异常图方面取得了相当大的进展，但仍有几种模型在考虑中，它们在地壳年龄和开放方案上各不相同。在本文中，我们提出了四个这些模型的审查。专注于极旋转，合成等时线和流线，我们进行倒退的时间开始于Chron 34（83.5马），因为它是相对明确的海洋宽，目前的地壳年龄图，显示估计的痕迹南美-南极洲-非洲三重连接每个模型。我们还使用相同的投影和比例绘制了所有模型在四个选定时期的重建图，以便于比较。在每一个关于板块碎裂的案例中，都需要做出各种各样的简化假设，以解释众多的同裂谷盆地和拉伸时期，这强烈表明刚性板块构造对于当前的问题来说是一个过于简单的模型。引用：Ghidella，M. E、L. A. Lawver和L. M. Gahagan（2007），冈瓦纳的分裂和南大西洋的开放：对现有板块构造模型的回顾，载于南极洲：变化世界中的基石-第10届ISAES在线会议记录，由A. K.库珀和C. R. Raymond等人，USGS公开文件报告2007-1047，短研究论文055，5页; doi：10.3133/of2007-1047.srp055
The opening history of both the Weddell Sea and South Atlantic Ocean is critical to understanding the breakup of Gondwana and the evolution of Antarctica since Early Jurassic times. The dispersal of the Gondwanide fragments is important to understanding the development of past ocean circulation. Unfortunately the tectonics of the Weddell Sea region is difficult to resolve because of the paucity of data coverage and the region’s inherent complexity. Although considerable progress has been achieved in the past 20 years with new marine aeromagnetic data and satellite derived gravity anomaly maps, there are still several models in consideration which differ in crustal ages and schemes of opening. In this paper we present a review of four of those models. Focusing on poles of rotation, synthetic isochrons and flowlines, we proceed backward in time beginning at Chron 34 (83.5 Ma), as it is relatively well defined ocean wide, and present crustal age maps that display the estimated trace of the South America-Antarctica-Africa triple junction for each model. We also plot reconstructions at four selected epochs for all models using the same projection and scale to facilitate comparison. The diverse simplifying assumptions that need to be made in every case regarding plate fragmentation to account for the numerous syn-rift basins and periods of stretching are strong indicators that rigid plate tectonics is too simple a model for the present problem. Citation: Ghidella, M. E., L. A. Lawver, and L. M. Gahagan (2007), Break-up of Gondwana and opening of the South Atlantic: review of existing plate tectonic models, in Antarctica: A Keystone in a Changing World – Online Proceedings of the 10th ISAES, edited by A. K. Cooper and C. R. Raymond et al., USGS Open-File Report 2007-1047, Short Research Paper 055, 5 p.; doi:10.3133/of2007-1047.srp055