Arid environments form in response to a combination of arid or semi-arid climate and a topography that results in the pervasive formation of brine and associated mineral deposits. The salts originate as dissolved solids in the rainfall and from the weathering of minerals as the rain infiltrates in the uplands and flows as groundwater to discharge in the lowlands where salt accumulates. The minerals that develop are a function of the input of dissolved constituents, leakage of solutes from the basin, thermodynamic state of the brines, water vapour content of the atmosphere, and the dynamic interplay between hydrology and thermodynamics with varying temperatures driving the resulting mineral assemblages.
In the resources section, this academic site has a free downloadable data set of PALEOMAP PaleoAtlas for GPlates, as compiled by Christopher Scotese.
GPlates is downloadable software allowing the user to visualise interactive plate-tectonic reconstructions with geographic information system (GIS) functionality and raster data visualisation. GPlates enables both the visualisation and the manipulation of plate-tectonic reconstructions and associated data through geological time. GPlates runs on Windows, Linux and MacOS X.
Excellent site for keeping up to date on what is happening across the geological sciences.It also has links to a variety of geo-courses, maps and software download sites.
GeoMapApp is a downloadable earth science exploration and visualisation application (runs on Windows, Linux and MacOS X) with direct access to the Global Multi-Resolution Topography compilation that hosts high resolution (~100 m node spacing) bathymetry from multibeam data for ocean areas and ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) and NED (National Elevation Dataset) topography datasets for the global land masses. It also allows one to load in a GIS format a range of other geological, geophysical and environmental data sets.
This is SEPM’s stratigraphy web site with open access to quality material and datasets. All material can be copied or downloaded and covering most aspects of sedimentary geology, including sections that focus on carbonates and evaporites with explanation levels ranging from more basic to highly detailed
This comprehensive guide covers:
• The history, sources, and symbolic meanings of 14 precious and semi-precious gems
• Mining practices, treatments and enhancement methods used to prepare gems
• Modern factors that affect gemstone values
• Modern uses of gemstones, including custom birthstone jewellery, healing purposes, and harnessing spiritual properties
• Additional resources to learn more about gems