高分辨率层序地层学作业.doc

Workshop1 One-dimensional simulation of shallow marine stratigraghic architecture resulting from the interactions among eustasy , tectonic , subsidence and sediment supply
Objective:
To examine, through graghical one-dimensional modeling, the concepts of eustasy, tectonic subsidence, sediment supply or production, resultant changes in water depth and modation potential. The interactions of these fundamental processes govern the geometry and lithofacies distributions of ic sequences.
Procedures:
We will assume an hypothetical eustatic curve, a constant rate of tectonic subsidence, and a constant rate of sediment supply and erosion. We will assume also that we are examining the results of these interactions on a shallow marine shelf of a passive continental margin.
Figure 1 shows a hypothetical eustatic curve. Inflection points on the curve are labeled 1-4. The rates of changes (first derivatives of the curve at each point) are given as:
1: -
2:+
3:-2,5m/1000yr
4:+
What are the rates of eustatic change at points a, b , c and d ? Label them
On figure 2 , plot the rates of eustatic change.
Let us define “modation potential” as the continuously varying, cumulative volume being created or removed by the interaction of eustatic change and tectonic subsidence. This volume is the maximum limit of sediment fill at a particular location through time increments. We might also define “modation rate” as the incremental addition or removal of space per unit time.
Assume that tectonic subsidence at this position on the shelf is a constant value of 20cm/1000yr. On figure 2, in another color, draw the curve of modation rate[use the same scalar units as shown on the left side of the figure].
On figure 3, plot the cumulative tectonic subsidence assuming again that tectonic subsidence at this position on the shelf is a constant value of 20cm/1000yr. Assume the origin of the subsidence curve is zero.
Again assuming that tectonic subsid