复杂造山带地区三维地质填图中深部地质结构的约束方法:西准噶尔克拉玛依后山地区三维地质填图实践

Constraining Deep Geological Structures in Three-Dimensional Geological Mapping of Complicated Orogenic Belts:A Case Study from Karamay Region,Western Junggar

在地球物理资料稀少、钻孔数据匮乏的复杂造山带地区进行三维地质填图,目前尚处于实践探索阶段.我们的填图工作思路是:以精细地表地质调查为基础,在地质-地球物理-钻孔等多源数据约束下,充分利用野外走廊带解析剖面、实测自然剖面、地球物理解释剖面等资料,进行人机交互式三维地质建模,并根据使用资料的准确性、空间分辨的精细程度等对模型的可靠程度进行分块评价.浅表层以地表地质信息(包括产状、地层层序关系、地层厚度、褶皱形态、断层性质与位移、局部和区域概念地质模型等)约束为主,深部地质结构则主要依据地球物理剖面资料,少量钻孔资料不仅用以校验地球物理资料解释的可靠性,并对模型施加强约束.以西准噶尔克拉玛依后山地区三维地质填图为例,着重讨论了在三维建模中如何具体实现上述思路和约束方法.实践证明,该填图思路和建模方法是行之有效的,可操作性强.

Three-dimensional geological mapping in the complicated orogenic belts is still in the testing stage due to inadequategeophysical and drill-hole data in the region.In this paper,we propose a method of three-dimensional geological modelling by using the measured natural profiles and the geophysical profiles under the constraints of detailed surface geological investigation data and the geology-geophysics-drilling data.The modelling reliability is evaluated based on the accuracy of the data and the spatial resolution.The surface structures are constrained by the surface geological information,including the attitudes,stratigraphic sequence and thickness,fold morphology,fault feature,and the local and regional conceptual geological models.The deep geological structures are mainly based on the geophysical profile data,in combination with proper drilling data which act as not only a test of the reliability of the geophysical interpretation but also an enhancement of the model.This paper takes the three-dimensional geological mapping of the Houshan area in Karamay as an example and discusses the detailed procedure in realizing the above-mentioned scheme,which shows both high efficiency and operability.