Sedimentary

Submarine Mass Movement

Submarine mass movement processes, driven by gravitational forces, represent an important mechanism whereby vast amounts of sediment are rapidly transported downslope and redistributed into deep-water from an originally shallow-water setting, and their deposits are widely recognised in continental margins. Although there is a tendency to consider these processes independently, there is an increasing awareness that in many cases these processes need to be integrated to produce a model of margin development. The mass movement processes display large temporal and spatial variations and have different importance, but their interrelationship needs to be understood and background sedimentation processes must be considered. Increasing knowledge of mass movement processes on the continental slope also has interest for natural hazard assessment.

Introduction to Carbonates

Carbonates are rocks composed mainly of calcium carbonate, CaCO₃. Some examples of common carbonate rocks are limestones and chalk. Carbonates form by precipitation from water; either straight from the water, or induced by organisms, to make their shells or skeletons, and they form in many environments (Figure 1).

Introduction to Sedimentology

Sedimentary rocks are made by the accumulation of particles of older rocks, either as clasts (chunks of rocks) or as mineral grains, chemically or biogenically precipitated. Clastic sedimentary rocks are principally classified on the basis of grain size and then further divided in terms of mineralogy. One of the most important things sedimentary rocks can tell us about is palaeoenvironments - ancient environments. This is done by looking at the sedimentary structures and the fossils contained within the rocks.

Ooid Formation

Ooids are spherical or ellipsoid concretions of calcium carbonate, usually less than 2mm in diameter (Donahue, 1969; Tucker and Wright, 1990). There have been examples in the Neoprotozoic of ooids that are 16mm in diameter (Sumner, 1993), but all modern ooids are 2mm or less. The interior of an ooid is usually composed of a nucleus, which is surrounded by a cortex of calcite or aragonite crystals that are arranged radially, tangentially or randomly (Figure 1). These crystals are arranged in concentric lamina.

GeologyRocks

Sedimentary

Submarine Mass Movement

Introduction to Carbonates

Introduction to Sedimentology

Ooid Formation

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