What is Geology? Definition and Explaination

Geology, from the Greek geo, “Earth,” and logos, “discourse.”

It is the science that pursues an under-standing of planet Earth. Geology is traditionally divided into two broad areas—physical and historical. Physical geology examines the materials composing Earth and seeks to understand the many processes that operate beneath and upon its surface (Figure 1.1). The aim of
historical geology, on the other hand, is to understand the origin of Earth and its de-velopment through time. Thus, it strives to establish a chronological arrangement of the multitude of physical and biological changes that have occurred in the geologic past. The study of physical geology logi-cally precedes the study of Earth history because we must first understand how Earth works before we attempt to unravel its past. It should also be pointed out that physical and historical geology are divided into many areas of specializa-tion. Table 1.1 provides a partial list. Every chapter of this book represents one or more areas of specialization in geology.
To understand Earth is challenging because our planet is a dynamic body with many interacting parts and a complex history. Throughout its long existence, Earth has been changing. In fact, it is changing as you read
this page and will continue to do so into the foreseeable future. Some-times the changes are rapid and violent, as when landslides or volcanic eruptions occur. Just as often, change takes place so slowly that it goes unnoticed during a lifetime. Scales of size and space also vary greatly among the phenomena that geologists study. Sometimes they must focus on phenomena that are submicroscopic, and at other times
they must deal with features that are continental or global in scale.
Geology is perceived as a science that is done in the out of doors, and rightly so. A great deal of geology is based on measure-ments, observations, and experiments conducted in the field. But geology is also done in the laboratory where, for example, the study of various Earth materials provides insights into many
basic processes. Moreover, the development of sophisticated computer models allows for the simulation of many of our planet’s complex systems. Frequently, geology requires an un-derstanding and application of knowledge and principles from physics, chemistry, and biology. Geology is a science
that seeks to expand our knowledge of the natural world and our place in it.

Figure 1.1 Rocks contain information about the processes that produce them. This large exposure of igneous rock in California’s Sierra Nevada was once a molten mass found deep within Earth. Geologists study the processes that create and modify mountains such as these.(Photo by St. Clair, Felix)

Geology gives insight into the history of the Earth, as it provides the primary evidence for plate tectonics, the evolutionary history of life, and past climates. In modern times, geology is commercially important for mineral and hydrocarbon exploration and exploitation and for evaluating water resources. It is publicly important for the prediction and understanding of natural hazards, the remediation of environmental problems, and for providing insights into past climate change. Geology plays a Vital role in Geotechnical / Geological and Civil engineering and is a major academic discipline.