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A "quadrangle" is a topographic map produced by the United States Geological Survey (USGS) covering the United States. The maps are usually named after local physiographic features. The shorthand " quad " is also used, especially with the name of the map; for example, "the Ranger Creek, Texas quad".
The various features shown on the map are represented by conventional signs or symbols. For example, colors can be used to indicate a classification of roads. These signs are usually explained in the margin of the map, or on a separately published characteristic sheet. [17] Topographic maps are also commonly called contour maps or topo maps.
The Shinumo Quartzite also known as the Shinumo Sandstone, is a Mesoproterozoic rock formation, which outcrops in the eastern Grand Canyon, Coconino County, Arizona, (Northern Arizona).
Mineral symbols (text abbreviations) are used to abbreviate mineral groups, subgroups, and species, just as lettered symbols are used for the chemical elements. The first set of commonly used mineral symbols was published in 1983 and covered the common rock-forming minerals using 192 two- or three-lettered symbols. [ 1 ]
A geologic map or geological map is a special-purpose map made to show various geological features. Rock units or geologic strata are shown by color or symbols. Bedding planes and structural features such as faults , folds , are shown with strike and dip or trend and plunge symbols which give three-dimensional orientations features.
On maps published by the United States Geological Survey (USGS) and the United States Armed Forces, true north is marked with a line terminating in a five-pointed star. [5] The east and west edges of the USGS topographic quadrangle maps of the United States are meridians of longitude , thus indicating true north (so they are not exactly parallel).
Each quadrangle is a region covering a specified range of latitudes and longitudes on the Martian surface. The quadrangles are named after classical albedo features , and they are numbered from one to thirty with the prefix "MC" (for "Mars Chart"), [ 1 ] with the numbering running from north to south and from west to east.
[1] [2] [3] Its geologic history, therefore, records with considerable clarity some of the earliest and most violent events that took place in the inner Solar System. The Bach quadrangle is south of Discovery quadrangle. To the west is Michelangelo quadrangle, and to the east is Debussy quadrangle.