Discrete Element Simulations of Cohesive Contractional Wedges: Kinematics and Mechanics of Fold and Thrust Belts

该研究将使用离散元方法对褶皱和冲断带进行数值模拟，以便更好地了解在一系列条件下对其结构几何形状和演变负责的控制和机制。这类正演模拟是检验和完善野外观测到的褶皱和冲断带解释的重要工具，这些褶皱和冲断带通常暴露有限，受到高度侵蚀，并在远离其形成条件的条件下保存下来。具体问题包括：（1）褶皱冲断带中控制断层聚散的物理力学参数是什么，特别是最前缘构造的成因和演化，这些构造是烃类的常见圈闭。(2)滑脱和基底非均质性在褶皱冲断带的力学状态和构造演化中起什么作用？（3）特定的基底结构和地层对褶皱和冲断带的构造影响是什么？模拟将进行使用RICEBAL，在莱斯大学开发的代码; 2D和3D模拟将进行检查的影响，机械地层，非均质滑脱性能和结构，和压痕。结果将比较自然的例子，特别是，经典的加拿大科迪勒拉山脉和北方阿巴拉契亚山脉在加拿大。褶皱冲断带的发育代表了一个基本的造山过程，也是形成丰富油气藏的原因。了解有利于油气聚集的独特前缘结构的条件，可以对未来前景的位置进行一阶预测。在这个项目中进行的模拟将提供一个独特的，但安全的方式来探索相关的地球动力学过程，广泛应用于许多其他问题。此外，这一项目还将进一步完善莱斯大学开发的离散单元法代码RICEBAL，该代码将通过地球动力学计算基础设施更广泛地分发给教育和研究。

The research will conduct numerical simulations of fold and thrust belts using the discrete element method in order to develop a refined understanding of the controls and mechanisms responsible for their structural geometries and evolution under a range of conditions. Forward modeling of this sort is an important tool for testing and refining interpretations of fold and thrust belts observed in the field, which often have limited exposure, are highly eroded, and are preserved under conditions far from those in which they were formed. Specific questions to be addressed include: (1) What physical and mechanical parameters control fault vergence in fold and thrust belts, with particular attention to the origin and evolution of the most frontal structures which are common traps for hyrocarbons? (2) What is the role of decollement and basement heterogeneity in the mechanical state and structural evolution of fold and thrust belts? And (3) What are the structural consequences of specific basement configurations and stratigraphy on fold and thrust belts? The simulations will be carried out using RICEBAL, a code developed at Rice University; 2D and 3D simulations will be carried out to examine the effects of mechanical stratigraphy, heterogeneous decollement properties and structure, and indentation. Results will be compared with natural examples, in particular, the classic Canadian cordillera and the northern Appalachians in Canada.Fold and thrust belt development represents a fundamental mountain building process and is also responsible for the formation of rich oil and gas reservoirs. Understanding the conditions responsible for distinctive frontal structures that favor hydrocarbon accumulations allow first-order predictions of locations of future prospects. The simulations carried out in this project will provide a unique, and yet safe, way to explore the associated geodynamic processes, with broad applications to many other problems. In addition, this project will enable further refinement of the discrete element method code RICEBAL, developed at Rice University, which will be made available for broader distribution for education and research through the Computational Infrastructure for Geodynamics.