5 Fossil Hydrothermal Systems

Abstract

Reactive transport modeling of the history of fossil hydrothermal systems provides the basis for understanding genesis of ore deposits as well as progress of diagenetic processes. The first part of this chapter presents a brief overview about applications of numerical simulations done by other authors investigating these topics. This is followed by a detailed examination of possible formation scenarios for the observed and considerable anhydrite cementation found at the location Allermöhe in Germany. For that purpose the SHEMAT software has been used in order to numerically determine the thermal-reactive flow-deformational history of the site. In order to explain the observed anhydrite cementation against the background of the entire geologic history of the Allermöhe site the fluid flow, heat transfer, transport, and chemical reaction model has been coupled with a sequence of geologic structures reflecting the stratigraphic development of the site.