Since the era of using aerial photography to identify areas where crops, fences, land boundaries, rocks and other geographical features interfaced with potential mineral finds, the science and technology of aerial and space photography to identify geological features has vastly expanded to fantastic levels of creating imagery along various wavelengths, using technology to look under the Earth’s crust, and of identifying the particular type and structure of rock.
In Satellite technology, multispectral sensors are now available to see the structure of the Earth’s surface in ways that the human eye cannot see. Sensors that use the infrared, near infrared, thermal infrared and short wave technology are installed on the Aster, Landsat 7+etm, and Worldview 2 satellites. With the ability to determine texture and petrology from miles above the Earth’s surface, locating, analyzing, identifying and mapping the structure and composition of the Earth’s surface is now greatly advanced.
The reflective and absorptive properties, plus the lithology of soils, rocks and vegetation can now be analyzed using multispectral imaging to identify various exposed mineral structires. The differences in absorption and reflection are analyzed and translated into assigned colors that are differentiated for each type of rock and for each group of wavelengths. When infrared bands 3, 2 and 1 are used, for example, vegetation appears as red, snow and dry salt lakes are white, and exposed rocks appear as brown, gray, yellow and blue. Other wavelengths identify clay, sulfites and carbonite, based on their absorption and reflection qualities, which are then translated into colors for the final image. Even more wavelengths identify carbonite, quarts and mafic volcanic rocks.
Finally, programs for translating the combined data and imagery into three dimensional, mosaic, and other forms for scientific analysis, such as probability of environmental impact, vegetation studies, and a host of layovers that identify man made structures or even ownership, zoning and code restrictions or allowances.
As a result, the combination of earthbound data collection and databases and the advanced aerial multi spectral imagery have created enough work for geologists, institutions, and businesses to last a while!
Geochemical surveys use identification and analysis of chemical abnormalities to determine if, for example, high levels of hydrocarbons or minerals. Where such levels had to be detectable to the human senses, they can now be measured in parts per million. Such techniques are used in two areas: prospecting for oil and gas; and prospecting for metallic mineral deposits. The development of far more sensitive, portable, and effective mass spectrometry, gas chromatography, and other equipment has created many opportunities for locating anomalies or concentrations of material that may indicate a significant deposit.
There was a unique microbial methods of mineral exploration, using analysis of concentrations of Bacillus Cereus spores to determine how their affiliation with Mesquite, and Au, or gold ,may indicate significant concentrations of gold.
Satimaging Corp, Introduction to Satellite imaging
Science Direct, Mesquite/Cereus Bacillus Case Study
Geochemical Surveys
