Geologists use a variety of instruments and materials to map an area's rock layers.
Geologists map areas of the Earth to work out the geologic history and structure of the rock layers. Geologic mapping helps scientists identify hazards and locate natural resources such as minerals, gas, oil, and water. Geologic mapping in the United States began in the late 18th Century. Today, geologists with the United States Geological Survey and at universities, as well as those working for private companies such as oil companies, perform most geologic mapping activities.
Compass
Geologists use a compass to navigate through the terrain and as a mapping aid to pinpoint locations on a topographic map when they are in the field. Geologists often rely on a Brunton compass in the field because it is designed for accuracy and for use in measuring the strike and dip (orientation) of sedimentary rock layers.
Hydrochloric Acid
Hydrochloric acid will form bubbles when applied to the surface of calcite-containing rocks such as limestone. Geologists may carry small dropper bottles of hydrochloric acid in the field to help quickly identify whether a rock sample contains calcite.
Hand Lens
Geologists use hand lenses, also called hand magnifiers, in the field for use in identifying the minerals or small fossils contained in a rock sample. Hand lenses come in a variety of types and strengths. Hand lenses are often in a loupe style and are worn on a cord around the neck for easy access.
Field Book
Geologists use field notebooks to record their detailed findings when they are in the field mapping rocks or in the office studying their samples. Geologists write notes describing rocks and draw pictures and maps of what they see in the field for future reference, typically using a permanent pen or marker. To preserve their field notes, some geologists use notebooks that have waterproof paper.
Rock Hammer
Geologists use specially designed rock picks or hammers to break rocks and minerals in the field to collect samples for future study in the lab. One end of a rock hammer is flat, and the other is pointed.
Safety Goggles
Geologists wear safety goggles or glasses to protect their eyes from rock chips and other materials when studying and performing experiments with rocks and minerals in the field. Safety goggles are available at hardware stores or eyeglass shops.
Aluminum Storage Clipboard
Geologists often use aluminum storage clipboards with lids in the field. These clipboards are available at most office supply stores. They provide the geologist a writing surface and a place to store small items such as writing instruments, rulers, and sunscreen.
Maps and Photos
Geologists use topographic maps and aerial photographs when mapping. The field geologist will plot her location and sample information, as well as measured dips and strikes, on the maps and photos so she can create geologic maps using the field data. Topographic maps are available from the USGS and various retailers.
Tags: rock layers, they field, Geologic mapping, Geologists often, Hand lenses
