scratches in rock produced by glacial abrasion are called
Glacial striations
title: Abrasion (geology) text: Abrasion (geology) Abrasion is a process of erosion which occurs when material being transported wears away at a surface over time. It is the process of friction caused by scuffing, scratching, wearing down, marring, and rubbing away of materials. The intensity of abrasion depends on the hardness, concentration, velocity and mass of the moving particles. Abrasion generally occurs four ways. Glaciation slowly grinds rocks picked up by ice against rock surfaces. Solid objects transported in river channels make abrasive surface contact with the bed and walls. Objects transported in waves breaking on coastlines cause abrasion. And, finally, abrasion can be title: Abrasion (geology) text: caused by wind transporting sand or small stones against surface rocks. Abrasion, under its strictest definition, is commonly confused with attrition. Both abrasion and attrition refer to the wearing down of an object. Abrasion occurs as a result of two surfaces rubbing against each other resulting in the wearing down of one or both of the surfaces. However, attrition refers to the breaking off of particles (erosion) which occurs as a result of objects hitting against each other. Abrasion leads to surface-level destruction over time, whereas attrition results in more change at a faster rate. Today, the geomorphology community uses title: Abrasion (geology) text: crush smaller grains or particles and remove grains or multigrain fragments, but the removal of larger fragments is classified as plucking (or quarrying), the other major erosion source from glaciers. Plucking creates the debris at the base or sides of the glacier that causes abrasion. While plucking has generally been thought of as a greater force of geomorphological change, there is evidence that in softer rocks with wide joint spacing that abrasion can be just as efficient. A smooth, polished surface is left behind by glacial abrasion, sometimes with glacial striations, which provide information about the mechanics of abrasion under title: Abrasion (mechanical) text: Abrasion (mechanical) Abrasion is the process of scuffing, scratching, wearing down, marring, or rubbing away. It can be intentionally imposed in a controlled process using an abrasive. Abrasion can be an undesirable effect of exposure to normal use or exposure to the elements. Ancient artists, working in stone, used abrasion to create sculptures. The artist selected dense stones like carbonite and emery and rubbed them consistently against comparatively softer stones like limestone and granite. The artist used different sizes and shapes of abrasives, or turned them in various ways as they rubbed, to create effects on the softer stone's surface. title: Weathering text: causes underlying rocks to expand and fracture parallel to the surface. Intrusive igneous rocks (e.g. granite) are formed deep beneath the Earth's surface. They are under tremendous pressure because of the overlying rock material. When erosion removes the overlying rock material, these intrusive rocks are exposed and the pressure on them is released. The outer parts of the rocks then tend to expand. The expansion sets up stresses which cause fractures parallel to the rock surface to form. Over time, sheets of rock break away from the exposed rocks along the fractures, a process known as exfoliation. Exfoliation due to