STRATIGRAPHIC SOLUTION SETS FOR DETERMINING THE ROLES OF SEDIMENT SUPPLY, SUBSIDENCE, AND SEA-LEVEL ON TRANSGRESSIONS AND REGRESSIONS

Although identifying unequivocally the cause of transgressions and reg ressions from the rock record can be difficult, we can place limits on the possible combinations of sediment supply, subsidence, and sea lev el that could generate an observed stratigraphic sequence. Using simpl e geometric models that estimate maximum rates of change in the three controlling variables, and combining these with other limits derived f rom field observations, we can plot a solution set to define the most likely range of variations in these three primary controls on shorelin e migration. This approach shows the amount each controlling factor mu st change alone, or in concert, to account for the stratigraphy. These quantitative values can be used to decide what is geologically reason able and what is not. Although a unique solution may not be available, we can calculate the required parameters for the observed shoreline m igrations, which provide a basis for informed interpretations.