Geologic map

It is not always possible to properly show this when the strata are extremely fractured, mixed, in some discontinuities, or where they are otherwise disturbed.

Trend and plunge are used for linear features, and their symbol is a single arrow on the map.

The oldest preserved geologic map is the Turin papyrus (1150 BCE), which shows the location of building stone and gold deposits in Egypt.

This map is based on Nicolas Desmarest's 1768 detailed study of the geology and eruptive history of the Auvergne volcanoes and a comparison with the columns of the Giant's Causeway of Ireland.

[3] In 1807, Maclure undertook the self-imposed task of making a geological survey of the United States.

During the rigorous two-year period of his survey, he crossed and recrossed the Allegheny Mountains some 50 times.

[4][5] Maclure's map shows the distribution of five classes of rock in what are now only the eastern states of the present-day US.

Since 1974, for 30 years, there were many findings reported in various technical conferences on newfound geology islandwide, but no new publication was produced.

In 2006, Defence Science & Technology Agency, with their developments in underground space promptly started a re-publication of the Geology of Singapore, second edition.

Sheets of all scales (though not for all areas) fall into two categories: The maps are superimposed over a topographic map base produced by Ordnance Survey (OS), and use symbols to represent fault lines, strike and dip or geological units, boreholes etc.

In both cases the original OS Third Edition sheet margins and numbers are retained.

However, in areas where the bedrock is overlain by a significantly thick unconsolidated burden of till, terrace sediments, loess deposits, or other important feature, these are shown instead.