Tuesday 16 July 2019

The Oldest Geologic Map And Mapmakers

By Matthew Perry


When it comes to maps, there are many different types. In one case, a geologic map has nothing to do with travel. For, this type of map refers locations of interest based on geological aspects of different areas, such as that of fossils and rocks. As such, this type of map differs greatly from that of a road atlas or maps used by GPS systems.

In most cases, geologic data and strata are shown by colors and symbols to indicate a location based on land surface. Whereas, structural data such as plunges, lineages, folds and faults are shown with strikes and dips or trend marks. As a result, these markings often create a 3-D effect in the object.

Identifying and marking the surface area of the object can often be complicated. The use of contour lines can often help in illustrating the subsurface, surface and topographical areas. Whereas, when making such calculations, it is important to consider whether or not the object had been exposed to topsoil, backfill, bedrock or other related factors which could have effected the overall surface area.

Currently, the Turin Papyrus which continues to be well preserved is considered to be the earliest geological map on record. For, the papyrus dates back to 1150 BCE and contains gold and stone deposits from different areas of Egypt. As such, some theorists have suggested that the map may have been used during the building of the ancient pyramids. While a number of geologists, historians, philosophy enthusiasts, researchers, scientists and theologians believe this could be the case, there is no concrete proof as to the map and pyramids having any type of connection.

Whereas, the earliest map known to exist in the modern era dates back to 1771, the map which shows part of Auyergne is made from basalt using prisms, balls and other markings to denote different locations. While this is the case, there have been a number of other geological maps developed in different areas of the world since that time. As such, there have been a number of archaeological, geographical, geological and historical findings which may have never taken place if not for these early surveyors and mapmakers.

The first map of this kind to be developed in the United States was created and developed by William Maclure in 1809. Maclure traversed and surveyed what was then the entire country before creating the map. After which, the map resulted in one which denoted the location and types of geological settings in each and every state of the Union at the time.

The journey which Maclure took to survey and research different areas of the United States took the surveyor across the Allegheny mountains more than fifty times. One outcome of these crossings, a map denoting findings of five classes of rocks which now are believed to only exist in the Eastern states of what is now present-day America.

While most all geological maps are similar to the first one created by Maclure, many are now superimposed over topographical maps with a letter, symbol and color mark to describe the type of geological aspects in the area. While the color relates to the exposure of the bedrock from the surface, symbols are often used to show fossils, fault lines and other data. As such, these maps are used in a number of different areas including marine biology, geology, history, topology and earthquake sciences.




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