Post Middle Miocene Tectonomagmatic and Stratigraphic Evolution of the Victoria Land Basin, West Antarctica
Post Middle Miocene Tectonomagmatic and Stratigraphic Evolution of the Victoria Land Basin, West Antarctica
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DOI：
10.1029/2019gc008568
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发表时间：
2020-03
期刊：
影响因子：
3.7
通讯作者：
C. P. Wenman;D. Harry;S. Jha
中科院分区：
文献类型：
--
作者：
C. P. Wenman;D. Harry;S. Jha
利用地震反射和钻孔资料建立了四个区域不整合和三个局部不整合的结构图，这些不整合通过第四纪西南极裂谷系统制约了晚白垩世位于罗斯海西部的维多利亚陆盆(VLB)在中中新世后的演化。不整合面之间的地层等厚线图显示，裂谷作用在12-7.6 Ma之间主要是岩浆作用，沉降受盆地西北缘和沿盆地南部轴线被称为恐怖裂谷的构造带控制。在4.3 Ma以前的地层中，围绕火山地貌的沉积中心表明，火山载荷引起的挠曲作用对VLB南部此后的沉降模式的影响越来越大。其间7.6~4.3 Ma是伸展构造和岩浆作用对盆地形态产生强烈影响的过渡期。自4.3 Ma以来，随着建造罗斯岛的不同火山中心的喷发，在不同的时间和位置相继形成了一系列挠曲次盆地。综合起来，这些次盆地形成了一条弯曲的护城河，环绕着罗斯岛和紧邻其北的较小的火山中心。这些盆地的宽度表明，岩石圈的弯曲刚度范围为0.20×1019~12.96×1019N-m(弹性厚度为0.6~2.4公里)。
Seismic reflection and borehole data are used to create structure maps of four regional and three local unconformities that constrain the post middle Miocene evolution of the Victoria Land Basin (VLB), which is located in the western Ross Sea within the Late Cretaceous through Quaternary West Antarctic Rift System. Isochore maps of the strata between unconformities show that rifting was mostly amagmatic between 12 to 7.6 Ma, with subsidence controlled by faults bordering the northwest margin of the basin and in a tectonic zone along the southern basin axis known as the Terror Rift. Depocenters surrounding volcanic features in strata younger than 4.3 Ma indicate an increasing influence of flexure due to volcanic loading on the subsidence pattern in the southern VLB after this time. The intervening period, from 7.6 to 4.3 Ma, was a transitional period during which both extensional tectonism and magmatism exerted strong influences on basin morphology. Since 4.3 Ma, a series of flexural subbasins formed successively at different times and positions as the different volcanic centers that built Ross Island erupted. In composite, these subbasins form a flexural moat surrounding Ross Island and smaller volcanic centers immediately to the north. The widths of these basins indicate that the flexural rigidity of the lithosphere ranges from 0.20 × 1019 to 12.96 × 1019 N‐m (elastic thickness 0.6 to 2.4 km).