The Grenville Orogen explained? Applications and limitations of integrating numerical models with geological and geophysical dataThis article is one of a series of papers published in this Special Issue on the theme Lithoprobe - parameters, processes, and the evolution of a continent .
The Grenville Orogen explained? Applications and limitations of integrating numerical models with geological and geophysical dataThis article is one of a series of papers published in this Special Issue on the theme Lithoprobe - parameters, processes, and the evolution of a continent .
复制标题
格伦维尔造山带解释道？
DOI：
10.1139/e09-070
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发表时间：
2010
影响因子：
1.4
通讯作者：
Jamieson R
中科院分区：
文献类型：
--
作者：
Jamieson R
数值模型为构造过程提供了强有力的见解，特别是当它们的有效性可以与自然造山带的地质和地球物理观测相对照时。本文以格伦维尔造山带为例，解释了将造山带模型与数据成功整合的一些标准。模型设计必须通过与自然的比较来简化，以阐明控制造山演化的一级过程，这限制了模型结果再现地质观测的程度。对于格伦维尔造山带西部，观测到的地质性质变化表现为下地壳块体，强度从模型的外部到内部递减。go系列模型采用这种设计再现了格鲁吉亚湾和montracimal - Val d 'Or岩性探测样带的一级地壳结构。恒定收敛和停止收敛模型都产生了类似的几何形状，但只有停止收敛模型产生了正常意义上的剪切带，就像观察到的那样。ego系列模型结合了一个由较强的下地壳块体包围的初始弱带，预测了在格伦维尔造山带东部观测到的高压岩石的发掘，尽管这些模型结果的其他方面并不成功。对地球动力学模型最重要的检验是它以自洽的方式综合各种独立观测的能力。其他标准包括与地壳尺度几何、构造和变质史的一致性。根据这些标准，目前的模型相当好地解释了格伦维尔造山带西部同辐合期和后辐合期的演化，但要为该系统的东端建立一个完全令人满意的模型，还需要进一步的工作。
Numerical models offer powerful insights into tectonic processes, especially when their validity can be tested against geological and geophysical observations from natural orogenic belts. Here we explain some of the criteria for success in integrating orogenic models with data, using examples from the Grenville Orogen. Model designs must be simplified by comparison with nature to illuminate the first-order processes that control orogenic evolution, which limits the extent to which model results can reproduce geological observations. For the western Grenville Orogen, observed variations in geological properties are represented by lower crustal blocks with strength decreasing from the exterior to the interior of the model. GO-series models with this design reproduce the first-order crustal architecture of the Georgian Bay and Montréal – Val d’Or Lithoprobe transects. Both constant-convergence and stop-convergence models produce similar geometries, but only stop-convergence models produce normal-sense shear zones like those observed. EGO-series models, incorporating an initial weak zone bounded by stronger lower crustal blocks, predict exhumation of high-pressure rocks as observed in the eastern Grenville Orogen, although other aspects of these model results are not as successful. The single most important test of a geodynamic model is its ability to integrate diverse and independent observations in a self-consistent manner. Other criteria include consistency with crustal-scale geometry and structural and metamorphic histories. By these criteria, the present models account reasonably well for the syn- and post-convergent evolution of the western Grenville Orogen, but further work is required to produce a fully satisfactory model for the eastern end of the system.