Why do we study the GEOSPHERE?

The Geosphere is important because it defines much of the environment we live in, controls the distribution of minerals, rocks and soils and generates natural hazards that shape the land and impact humans. The distribution of mountains, position of continents, shape of the sea floor and location of major rivers and flood plains are all largely products of processes that occur in the Geosphere. The distribution of mineral resources, such as oil, coal, metal ores and even sand and gravel are critical to the economic success of most nations.
glacial_erosion
(Credit: Philip Dennison, UC-Santa Barbara)

The Geosphere is particularly important in the way it interacts with the other spheres. For example, the evolution of the modern atmosphere is believed to be a combined product of geologic processes (volcanic outgassing, rock weathering, iron oxidation) and biological processes such as photosynthesis. The primary source of carbon dioxide, which may lead to global warming, is fossil fuel mined from the Geosphere and used for energy production. Part of the water that makes up the world's ocean is believed to have originated from volcanic steam. Plant distributions, while largely controlled by global climate, vary in response to changes in elevation and the distribution of soils.

The Cryosphere interfaces with the Geosphere in the way that glacial ice carves and shapes alpine terrain at high latitudes and altitudes. Volcanic ash, in turn, can decrease planetary albedo and may be one way ice-ages are initiated. Over the longer term, global climate may vary depending on the distribution of continents. For example, closure of the seaway between the Atlantic and Pacific oceans during the formation of the Isthmus of Panama (~6 mya), may be in part responsible for the formation of ice ages over the last few million years. Clearly it is not possible to study any one sphere in isolation of the others.

Human beings are particularly dependent on the Geosphere. The Geosphere is that component of the Earth system where mineral wealth in the form of metals, coal and oil are found. Surface topography, combined with the movement of water across the landscape and distribution of fertile soils, is the dominant factor determining where we grow our crops and how successful that might be. For example, early civilizations in Asia, Africa and North and South America grew where conditions were good for growing crops. The most expensive natural disasters known to man are earthquakes and volcanoes, both of which occur along the margins of plates.

Isotopic geology forms only one of many new technologies used to study the geosphere. Other laboratory-based technological advances include the use of new instruments to determine rock and mineral composition, and advances in our understanding of magnetism and our ability to measure magnetic properties of materials. New analytical tools have revolutionized the way geologists describe rocks, which until recently were limited to what a human eye could see through a hand lens or microscope. Paleomagnetism has allowed geologists to determine not only when a rock formed, but the latitude where it formed and orientation of the rock as it cooled down and settled. Through paleomagnetism, geologists have been able to reconstruct past locations of continents and determine how far rocks have traveled from their origin.

In order to map and manage our resources, and plan for natural disasters, human beings must understand the Geosphere. In order to understand natural variation in global climate, and how human beings might impact climate, it is critical that we understand how the spheres interact, and the role the Geosphere plays.