3c: MARINE ENVIRONMENTS

Geographiclocation andplate tectonicsetting

Transportagent andmedium

Organicprocesses andorganismsthat modifysediments Climate

Sedimentary environment

Sediments deposited

Turbiditycurrents

Deep sea8

Continental shelf9

Organicreef

10

Continental margin/slope11

911

8

Marine Settings: #8-Deep Sea

Marine Settings: #9-Continental Shelf (shallow)

Marine Settings: #10-Organic Reef

Coral reefLight

Lagoon Open ocean

Carbonate platforms are built by reef-building organisms that precipitate calcium carbonate as calcite aragonite.

Light

Light Carbonate platform

Atoll formation: 1) Volcano, 2) reef forms, 3) volcano erodes

Quiz: MARINE ENVIRONMENTS

1 3

4

2

56

7

8

9 10

11

How do Sedimentary Rocks form?

Diagenesis

Process...turns sediment into sedimentary rocks

Requires: pressure, temperature, fluids

Most cements are Calcium Carbonate or Silica

Sedimentary Structures

Features formed at time of deposition

BEDDING: Horizontal layers of rock

Cross-bedding: Ripples, dunes, sandbars

Graded bedding

Ripples

Sedimentary Textures

Clues to the history of the rock

Grain size and angularity

Degree of sorting

Well-sorted, fine-grained

Poorly sorted, coarse-grained

Contact

Siliciclastic classification is based on grain size

Coarse: boulders and gravelMedium: sandFine: silt, mud, clay

Chemical Sedimentary Rocks