Structural and geodynamic modelling of the influence of granite bodies during lithospheric extension: Application to the Carboniferous basins of northern England
Structural and geodynamic modelling of the influence of granite bodies during lithospheric extension: Application to the Carboniferous basins of northern England
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岩石圈伸展过程中花岗岩体影响的结构和地球动力学模型：在英格兰北部石炭纪盆地的应用
DOI：
10.1016/j.tecto.2019.02.008
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发表时间：
2019
期刊：
影响因子：
2.9
通讯作者：
Howell L
中科院分区：
文献类型：
--
作者：
Howell L
典型的“块盆式”构造框架内的盆内隆起是由大型花岗岩体支撑的。人们普遍认为，这与花岗岩相对于可容纳地下室的相对“刚性”和“浮力”有关。有人认为，在构造伸展期间，花岗岩基岩外围地区的正断层使花岗岩核块体能够均衡地抵抗沉降，从而在广泛的断裂引起的沉降期形成稳定的区域。然而，一维模拟表明，密度相对较低的地壳不能以这种方式抵抗下沉。相反，当假定局部均衡时，花岗岩核盆地内高压的出现与花岗岩侵位后的初始均衡补偿有关。伸展构造作用期间不同的沉积物负荷夸大了这一剖面。一个完整的二维岩石圈数值模拟方法强调了弯曲刚性在限制振幅同时增加均衡偏转波长方面的作用。根据这些模型，认为这种响应留下了与欠补偿的花岗岩浮力和弯曲张力有关的残余二阶应力。通过结合地壳内的密度亏损、弯曲刚性、较浅次表层的简单剪切变形和较深次表层的纯剪切变形，可以复制所观察到的北奔宁盆地的盆地几何形状。采用这项技术，可以再现区域弯曲剖面对下伏花岗岩和大型伸展断裂的响应，从而在一定程度上得到验证。提出三个因素的相互作用决定了部分花岗岩、脆-韧性岩石圈的构造格局和盆地间隆起的出现：1)非构造的“二阶”应力，如岩石圈的弯曲响应和与花岗岩有关的残余的、补偿不足的浮力；2)伸展构造应力，重要的是；3)继承的基底组构。
Intra-basinal highs within classic ‘block and basin’ style tectonic frameworks are underpinned by large granite bodies. This is widely believed to relate to the relative ‘rigidity’ and ‘buoyancy’ of granite in relation to accommodating basement. It has been suggested that during periods of tectonic extension, normal faulting around the peripheral regions of granite batholiths permits granite-cored blocks to isostatically resist subsidence, thus forming stable areas during periods of widespread faulting-induced subsidence. However, one-dimensional modelling indicates that relatively less dense crust is incapable of resisting subsidence in this way. Instead, when local isostasy is assumed, the occurrence of granite-cored, intra-basinal highs relates to initial isostatic compensation following granite emplacement. Differential sediment loading during extensional tectonism exaggerates this profile. An integrated two-dimensional lithospheric numerical modelling approach highlights the role of flexural rigidity in limiting the amplitude whilst increasing the wavelength of isostatic deflection. In light of these models, it is suggested that such a response leaves residual second-order stresses associated with the under-compensated buoyancy of the granite body and flexural tension. The observed basin geometries of the Carboniferous North Pennine Basin can be replicated by incorporating a density deficiency within the crust, flexural rigidity, simple shear deformation within the shallower subsurface and pure shear deformation within the deeper subsurface. In adopting this technique, the regional flexural profile in response to underlying granite bodies and large extensional faults can be reproduced and thus, to an extent, validated. It is proposed that the interaction of three factors dictate the tectonic framework within a partially granitic, brittle-ductile lithosphere and the occurrence of inter-basinal highs: 1) non-tectonic, ‘second-order’ stresses such as the flexural response of the lithosphere and residual, under-compensated buoyancy forces in relation to granite bodies; 2) extensional tectonic stress and importantly; 3) inherited basement fabric.
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DOI：
10.1144/gsl.sp.1964.001.01.21
发表时间：
1964
期刊：
Geological Society, London, Special Publications
影响因子：
--
作者：
E. H. Francis;A. W. Woodland
通讯作者：
E. H. Francis;A. W. Woodland
影响因子：
2.7
作者：
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影响因子：
2.9
作者：
R. Scrutton;R. Dingle
通讯作者：
R. Dingle
影响因子：
2.7
作者：
G. Johnson
通讯作者：
G. Johnson
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影响因子：
2.7
作者：
S. Corfield;R. Gawthorpe;M. Gage;A. J. Fraser;B. Besly
通讯作者：
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