VARIATIONS IN EFFECTIVE ELASTIC THICKNESS OF THE NORTH-AMERICAN LITHOSPHERE
VARIATIONS IN EFFECTIVE ELASTIC THICKNESS OF THE NORTH-AMERICAN LITHOSPHERE
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DOI：
10.1038/343636a0
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发表时间：
1990-02-15
期刊：
影响因子：
64.8
通讯作者：
GRIEVE, RAF
中科院分区：
文献类型：
--
作者：
BECHTEL, TD;FORSYTH, DW;GRIEVE, RAF
岩石圈对载荷的均衡响应通常可以成功地用一个模型来表示，在该模型中，地球表面地形地物的重量部分由覆盖在无粘性软流层上的弯曲弹性板内的应力支撑，部分由与伴随弯曲1的密度界面的偏转相关的浮力支撑。以前根据沉积盆地的形状或伴随断层滑动的变形估计北美弹性板的表观厚度3-10，范围从几公里到一百多公里-或相当于，挠曲刚度约为1021~1025N m−1。在这里，我们使用一种不限于沉积盆地的挠曲刚度估计技术来绘制北美岩石圈有效弹性厚度的变化。有效弹性厚度的范围从盆地和山脉省的最小∼4公里到大陆前寒武纪核心的100公里，支持了自上次热事件以来弯曲刚性随时间增加的观点11。
THE isostatic response of the lithosphere to loading can often be successfully represented by a model in which the weight of topographic features on the Earth's surface is supported in part by stresses within a flexed elastic plate overlying an inviscid asthenos-phere, and in part by the buoyancy forces associated with the deflection of density interfaces accompanying flexure1,2. Previous estimates3–10of the apparent thickness of the elastic plate in North America, based on the shapes of sedimentary basins or the deformation accompanying slip on faults, range from a few to more than a hundred kilometres—or equivalently, flexural rigidities ranging from about 1021to 1025N m−1. Here we use a technique for estimating flexural rigidity that is not limited to sedimentary basins to map variations in the effective elastic thickness of the North American lithosphere. The effective elastic thickness ranges from a minimum of ∼4 km in the Basin and Range Province to >100 km in the Precambrian core of the continent, supporting the idea that flexural rigidity increases with time since the last thermal event11.