clastic sedimentology introduction

Textbook: Introduction to Clastic Sedimentology

Downloadable from:http://spartan.ac.brocku.ca/~rcheel/teaching/sedimentology/SedNotes/

Topics to be covered:

1. Grain Texture (fundamental descriptors of granular material)

Grain size

Grain shape

Porosity and permeability

Grain orientation

2. Classification of terrigenous clastic rocks.

Arenite

Rudite

Lutite

3. Unidirectional fluid flow and sediment transport

Characteristics of unidirectional flows

Simple fluid flow

Fluid gravity flows

Sediment transport

Modes of transport

Initiation of transport

4. Bed forms and stratification under unidirectional flows

Bed forms

Terminology

The sequence of bed forms

Bed form stability fields

Cross-stratification formed by bed forms.

Terminology

Origin of cross-stratification

Cross-stratification and bed forms.

5. Flow, bed forms and stratification under oscillatory and combined flows

Characteristics of gravity waves

Bed forms and stratification under symmetrically oscillating currents

Bed forms and stratification under combined flows

The enigma of Hummocky Cross-stratification

Clastic Sedimentology:

The study of sediment and sedimentary rocks that are made up of particles that are the solid products of weathering at or near the Earth’s surface.

Gravel Sand Mud (silt and clay)

Conglomerate Sandstone Siltstone and Shale

Purpose of the course:

To introduce terminology and fundamental concepts for the description and interpretation of clastic sediment and sedimentary rocks.

Why study clastic sediment?

Sedimentary rocks make up only 7.9% of the Earth’s crust.

66% of the surface of the Earth is covered by sediment or sedimentary rocks.

Humans interact with the Earth largely at or near its surface.

At the same time they…..

Modify its physical and chemical properties so that it is no longer useable by them.

It is important to understand the various properties of the sedimentary cover and have systematic methods for describing these properties.

Hide garbage and other waste material in it.

Based on the recognition of the signature of changing environments over time, as preserved in the rock record.

Environmental interpretation of rocks

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Age of rocks

= Earth History

Sedimentary rocks record the history of changing environments on Earth.

Large scale cross-bedding in 240million year old rocks in the Central US.

= windblown sand dunes; the Central US was a desert at thattime.

By examining the characteristics of various environments on Earth today we can interpret the environments in which ancient sediments were deposited.

The present is the key to the past.

Environmental interpretation: