Subsidence
Subsidence
may be the effect of local tectonic activity or sediment loading. The latter occurs when the weight of overlying
sediment exceeds the resistive strength of the underlying strata.
This results in supportive yielding and subsequent subsidence.
Effectively, this situation increases the depth of the water column
overlying the subsided section, a situation similar to a rise in sea level
except on a very local scale. The
local carbonate productivity and sedimentation rates will be affected in ways
similar to an increase in base level depending on the rate of subsidence. Generally, the rate of subsidence from sediment
loading is slow enough for the carbonate factory to keep up with the resulting
water deepening, however some tectonic processes may result in platform drowning.
For further information see Sea Level
Changes, Water Depth, and Eustatic Responses.
Proceed on to the carbonate platform question set.