Core-log-seismic integration in hard rock environments using the ICDP drilling project COSC-1, Sweden

本研究将在ICDP项目“斯堪的纳维亚加里东尼德斯碰撞造山运动”（COSC）的框架下，对斯堪的纳维亚加里东尼德斯的地质构造和岩石物理性质进行详细研究。其目标是获得对关键造山过程的新见解，如推覆就位，并建立一个合理的基础，将加里东尼德山脉与现代类似的山脉（如喜马拉雅山脉）进行比较。本文的主要目的是利用岩心-测井-地震综合（CLSI）技术，在COSC遗址及附近地区建立Seve推覆复合体的高分辨率地震地层学。这将有助于识别西弗推覆复合体变质层序的独特岩石物理特征，并有助于提高对其演化的认识。此外，利用现有的高分辨率和VSP校准的2D和3D地震成像，这些信息将被外推到一个大尺度模型中。准确的地下特征不仅需要反射地震分析，还需要高分辨率岩石物理岩心和地球物理测井数据集的集成。为了实现这一目标，必须对岩心、井下测井和地震数据进行有效的合并和交叉校准，以揭示推覆体之间主要剪切带（据称已转变为糜棱岩）的结构和演化。我们的建议侧重于使用基于CLSI的跨学科方法研究岩石的地球和岩石物理性质。我们将整合岩心测量、测井数据和地震数据，这些数据在各自的测量尺度下具有不同的分辨率。CLSI方法已成功应用于海洋和湖泊环境以及许多IODP钻井项目。在本提案中，该技术将首次应用于硬岩石，这将需要开发CLSI晶体基底的新方法。之所以选择COSC项目，是因为该项目拥有出色的地震数据、井下测井数据和VSP数据，而且不同实验室目前正在对大量岩心样本进行几种岩石物理测量；所有研究这些数据的科学家都同意参与或支持这项工作。

This study will investigate in detail the geological structure and the petrophysical properties of the Scandinavian Caledonides within the framework of the ICDP project Collisional Orogeny in the Scandinavian Caledonides (COSC). The goal is to gain new insights into critical orogenic processes, such as nappe emplacement, and to establish a justified base for the comparison of the Caledonides with modern analogues, e.g. the Himalayas. The key objective of this proposal is to construct a high-resolution seismic stratigraphy of the Seve Nappe Complex at the COSC site and nearby areas by core-log-seismic integration (CLSI). This will allow identification of distinctive petrophysical characteristics of the metamorphic sequence of the Seve Nappe Complex and lead to an improved understanding of its evolution. Furthermore, this information will be extrapolated to a large scale model, using already existing high-resolution and VSP calibrated 2D and 3D seismic imaging. Accurate characterization of the subsurface requires not only reflection seismic analysis but also integration of high-resolution petrophysical drill core and geophysical well-log data sets. To reach this goal, a useful merging and cross calibration of core, downhole logging and seismic data is mandatory to shed new light on the configuration and evolution of the primary shear zones (supposedly transformed into mylonites) between nappes. Our proposal focuses on investigations of the geo- and petrophysical properties of the rock using an interdisciplinary approach based on CLSI. We will integrate core measurements, logging data and seismic data, which are of different resolution in the respective measurement scales. The CLSI method has been successfully applied in marine and lake environments and in many IODP drilling projects. In this proposal, the techniques will be applied to hard rock for the first time, which will require the development of new approaches of CLSI to crystalline basement. The COSC project has been chosen because excellent seismic data, downhole logging and VSP data are available and several petrophysical measurements are currently being performed by different labs on a large set of core samples; all scientists working on these data have agreed to be involved or support this work.