FORTRAN IV Computer Program for Simulation of Transgression and Regression with Continuous-Time Markov Models

Abstract

Continuous-time Markov models based on lateral movement of shallow marine and nonmarine environments during transgression and regression through continuous time can be adapted to a variety of lateral-shift processes, such as progressive facies changes across a sedimentary basin, onlap+offlap relations among stratigraphic rock bodies, etc. In this report a clastic-wedge model is used to generate equally spaced borehole or outcrop sections that show the type of deposits formed as the environments shift back and forth.

The states of the transgressive-regressive system can be defined in terms of the position of the strandline through time, with the accumulating sediments representing responses to particular environments as they successively occupy a given monitoring station. Simulations are performed with a transition-rate matrix instead of the conventional transition-probability matrix, although the latter can also be adapted to lateral-shift processes. These two kinds of matrices can be transformed from one to another, and a computer program for this purpose is listed in this report. The main simulation program is illustrated with an experimental example, and the body of the text discusses some of the implications involved in structuring Markov models as continuous-time, discrete-state mechanisms.