Stress in the lithosphere: Inferences from steady state flow of rocks
Stress in the lithosphere: Inferences from steady state flow of rocks
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DOI：
10.1007/bf01637104
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发表时间：
1977
影响因子：
2
通讯作者：
J. Mercier;Douglas A. Anderson;N. Carter
中科院分区：
文献类型：
--
作者：
J. Mercier;Douglas A. Anderson;N. Carter
稳态变形实验的力学数据和流动过程可以用来推断岩石圈和软流圈的应力状态。流动方程外推到代表性地质应变率10 - 14/秒。对于岩盐、大理石、石英岩、白云石、纯橄榄岩和顽火辉石，现在是有根据的，因为实验中的稳态流动过程与岩石中的相同，而且地热已经相当好地确定。更直接的估计是从自由位错密度，亚晶粒尺寸和再结晶晶粒尺寸得到的，所有这些都是应力的函数。使用这些技术中的最后一种，我们估计了应力分布与玄武岩和金伯利岩中捕虏体深度的函数关系，这些捕虏体的平衡深度是通过辉石技术确定的，来自次大陆和大洋下上地幔的四个不同区域。结果是相似的，表明在40至50公里处的应力差约为200至300巴，在100公里以下的深度衰减到几十巴。这些应力是合理的，并与力学数据的外推结果雅阁，前提是考虑到应变率随深度的增加而普遍增加，粘度随深度的减小。
Mechanical data and flow processes from steady state deformation experiments may be used to infer the state of stress in the lithosphere and asthenosphere. Extrapolations of flow equations to a representative geologic strain rate of 10−14/sec. for halite, marble, quartzite, dolomite, dunite and enstatolite are now warranted because the steady state flow processes in the experiments are identical to those in rocks and because the geotherms are reasonably well established. More direct estimates are obtained from free dislocation densities, subgrain sizes and recrystallized grain sizes all of which are functions only of stress. Using the last of these techniques, we have estimated stress profiles as a function of depth from xenoliths in basalts and kimberlites, whose depths of equilibration were determined by pyroxene techniques, from four different areas of subcontinental and suboceanic upper mantle. The results are similar and indicate stress differences of about 200 to 300 bars at 40 to 50 km, decaying to a few tens of bars at depths below 100 km. These stresses are reasonable and are in accord with extrapolations of the mechanical data provided that allowance is made for a general increase in strain rate and decrease in viscosity with depth.