What is the sedimentary sequence?
What is the sedimentary sequence?
Sedimentary sequences are layers of rock which are derived from weathered rocks, biogenic (= of living organisms) activity, or precipitation from solution. Sedimentary sequences are layers of rock which are derived from weathered rocks, biogenic activity, or precipitation from solution.
What is a transgressive sequence?
A marine transgression is a geologic event during which sea level rises relative to the land and the shoreline moves toward higher ground, which results in flooding. Transgressions can be caused by the land sinking or by the ocean basins filling with water or decreasing in capacity.
What are Sloss sequences?
A cratonic sequence is a very large-scale lithostratographic sequence in the rock record that represents a complete cycle of marine transgression and regression on a craton (block of continental crust) over geologic time. Cratonic sequences were first proposed by Laurence L. Sloss in 1963.
What is the sequence of rocks produced by a regression of the sea?
During a regression the sequence of rocks will show an offlap sequence (the facies will become shallower environments as you move up through the sediments).
What rock sequence indicates a marine transgression?
Look at the sequence in the Figure below and see if you can determine whether the sea was transgressing or regressing. At the bottom, the Tonto Group represents a marine transgression: sandstone (11), shale (10), and limestone (9) laid down during 30 million years of the Cambrian Period.
What is a regression in sea level?
A marine regression is a geological process occurring when areas of submerged seafloor are exposed above the sea level. Regressions are, therefore, seen as correlates or symptoms of major extinctions, rather than primary causes.
What were the two major cratonic sequences in the late Paleozoic?
Explain and define the major cratonic sequences—Kaskaskia, Absaroka—of North America during Late Paleozoic.
When did the Tippecanoe sequence end?
The massive evaporite deposits of the Michigan Basin were created during this period. The Tippecanoe sequence ended with a regression in the early Devonian, to be followed later by the Kaskaskia sequence.
What is a regressive sequence?
When the water level in the ocean basins is at a lower level than their capacity, the sea starts to expose the previously covered lands. The submerged seafloor is exposed as a result. This process is known as regression.
Is a regressive sequence fining or coarsening upwards?
As a result, a transgressive sequence will have finer-grained facies overlying coarser-grained facies (fining-upward from sand at the bottom, and then to silt, and then to shale). As a result, a regressive sequence will have coarser-grained facies overlying finer-grained facies (coarsening-upward).
What is an epeiric sea?
Definition of epeiric of a shallow sea : that covers a large part of a continent while remaining connected with the ocean — compare epicontinental
What is an epicontinental sea?
Epicontinental or epeiric seas represent shallow oceanic bodies resulting from the flooding of continental interiors. They are differentiated from the flooded continental margins of ocean basins—so-called shelf seas—in that they extend into the center of continents. Because maximum sea-level rise during the Phanerozoic has been
What is the name of a sea that covers continental rock?
Seas that cover continental rock are called epicontinental or epeiric seas. Deep ocean basins are almost never preserved in the rock record (and when they are they are pinched out and metamorphosed during continental collisions).
What is an example of eustatic sea level?
In modern times, continents stand high, eustatic sea levels are low, and there are few inland seas, the largest being Hudson Bay. Modern examples might also include the recently (less than 10,000 years ago) reflooded Persian Gulf, and the South China Sea that presently covers the Sunda Shelf.
