Lec 7 - Clastic and Carbonate Dep Environs

Lec 7 - Clastic and Carbonate Dep Environs - REVIEW LEC 7...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
REVIEW LEC 7 – CLASTIC AND CARBONATE DEPOSITIONAL ENVIRONMENTS “The Present is the Key to the Past” Geologists study present day environments to recognize similar environmental characteristics in the rock record Environmental analysis helps petroleum geologists determine where to drill the next well. Clastic Depositional Environments Two broad categories: Terrestrial and Marine River System: o Alluvial Fan – Develop where a high gradient stream leaves a narrow mountain valley. (terrestrial delta) o Narrow Stream valley V-shaped Down cutting toward base level Features include rapids and waterfalls o Wide Stream Valley Stream near base level Downward erosion less dominant Stream energy directed from side to side – forms a flood plain Stream forms meanders o Braided Streams Highly variable volume of water discharge Bed load = sand and gravel Channels = wide and shallow Close to highlands/mountains and source of sediment o Wide Stream Valley – Meandering Stream Inside of bend = sand deposition in “point bar” deposit Outside of bend = erosion and “cut bank” Floodplain and back Swamp on either side of channel = source rock and seal Deltas: o Form when a rive enters the ocean or a lake o Consist of 3 types of beds Topset beds – horizontal and closest to land Foreset beds – cross beds that angle toward ocean Lec. 7 – page 1
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Bottomset beds – horizontal beds in front of delta sands – in the water o Develop several distributary channels that carry sediment across delta front and into the water. o
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

Page1 / 4

Lec 7 - Clastic and Carbonate Dep Environs - REVIEW LEC 7...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online