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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.

Introduction to Metamorphic Petrology

Metamorphic petrology is the study of rocks which have been changed (metamorphosed) by heat and pressure. They are broadly categorized into regional and contact. Metamorphism is an extension of the process which forms sedimentary rocks from sediment: lithification. However, all types of rocks; igneous, sedimentary and metamorphic, can all be metamorphosed. During metamorphism no melting takes place. All the chemical reactions which take place occur in the solid-state.

Introduction to Igneous Petrology

Igneous rocks are formed form the cooling of molten rock, magma. They are crystalline, which means they are made up of crystals joined together. There are many different types of igneous rocks but they fall into two (very) broad categories; intrusive and extrusive. Intrusive rocks are igneous rocks which form at depth. They cool slowly, taking tens of thousand of years to cool. They have large crystals, tens of millimetres in size. Extrusive rocks are those which have erupted from volcanoes.

Plate Tectonics: An Introduction

Plate tectonics is the theory that underpins most of modern geology. The basic idea is that the surface of the Earth is made up of several segments - plates. These plates move around the globe while being created and destroyed at their margis. This theory helps to explain many things, such as the rock types that indicate desert climates in north England. Rather than have to move the climatic belts, it is the continent itself that has moved.

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.

An Introduction to Structural Geology

Structural geology is the study of the features formed by geological processes. Features include faults, folds and dipping strata. Geologists can work out the order of events and see which events are related by taking fairly simple measurements and using simple methods.

An Introduction to Geology

Geology is, broadly speaking, the study of the Earth. It is split into several disciplines, including: Petrology (the study of rocks), Geophysics (the study of the Earth using physics), Palaeontology (the study of fossils) and Mineralogy (the study of minerals). The main aim of geology is to understand how the Earth works; how mountains are built, how the oceans form, what dinosaurs looked like. The Earth is constantly changing, both inside and outside.

GeologyRocks

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Introduction to Sedimentology

Introduction to Metamorphic Petrology

Introduction to Igneous Petrology

Plate Tectonics: An Introduction

Ooid Formation

An Introduction to Structural Geology

An Introduction to Geology

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