GeologyRocks

Geological Time

How do we know the age of the Earth? How do we know the age of rocks we find? There are two main ways to date rocks - absolute dating and relative dating. After the rocks have a date assigned to it, they can be put in some sort of order, and the relative dates worked out. This is the geological timescale.

The Ageing Earth

Plate Tectonics: The Evidence

The evidence for plate tectonics comes many fields, such as palaeontology, geophysics and climate study. The first evidence was the matching of continents and their rock types across oceans. This had been realised since the 17th Century. Theories of how continents moved were ad hoc at best. Alfred Wagner, an early 1900's German Meteorologist proposed that the continents of South America, Africa, India and Australia had been one continent in the past due to their similarity of fossils and palaeoclimate.

Meteor Craters

A meteorite is defined as any extraterrestrial solid mass that reaches the Earth's surface (Farris Lapidus, 1990). The term strictly extends from the nano scale e.g. dust particles, through to the macro scale e.g. 100s of metres in diameter (Zanda and Rotaru, 2001). However, the term meteorite is generally reserved for the larger particles that reach the Earth's surface.

Introduction to the Geological Features of the Moon

The Moon is the only natural satellite of the Earth and formed at about the same time, over four and a half billion years ago, but has not evolved in the same way. Lacking an atmosphere, water and life, and having cooled more rapidly due to its smaller size, much of the surface has not been changed significantly for billions of years.

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.

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.