GEOL 102 Historical Geology

Spring Semester 2017
Coastal & Marine Environments: Transgressions & Regressions

Coastlines are important: give us the interface between marine and terrestrial conditions. VERY ephemeral: can move inland or seaward very quickly.

Different types of environments where land meets sea.

Barrier Island-Lagoon Complexes

Sabkha - Arid coastlines

Reef-Lagoon Complexes

Coastlines are ephemeral: they move towards the ocean basin or towards the continent due to a number of factors:

All these produce one of two net effects:

Transgression-regression events allow geologists to see contemporary marine and terrestrial rocks due to intertonguing of facies.

Most of the planet's surface is underwater. In fact, the present has one of the lowest sea levels of Earth History (lowest of all seems to be recent interglacials). In other words, we are in an oceanic lowstand and the continents are mostly emergent. During other time periods, seawater covers most of the shallow parts of the continents: an oceanic highstand when the continents are submerged. 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). However, some relatively deep continental seas are preserved, and VAST amounts of sediment from epeiric marine rocks are known.

On the continent, or along continental shelves:
Siliciclastic Shelf Environments:

Carbonate Banks & Platforms:

Continental Slope Environments:

Pelagic Environments:

Pelagic sedimentary environments known mostly through deep-sea drilling, and are only rarely part of terrestrial rock record.

To Lecture Notes.

Last modified: 19 January 2017