Surface geology (direct observation and interpretation)
No doubt the importance of surface geology and exploratory procedure, as it was the first to be used for more than a century, to know the value of the fossils to determine the stratigraphic position of the rocks and recently, radiometric studies which set thechronological age of different types of rocks, especially igneous and metamorphic rocks.
The contribution of geologists and researchers allowed widely known geology of Mexico, they have all made significant contributions, each focusing on different objectives, whether in search of fossils, oil, land, economic resources (minerals, limestone, clay, etc. .) there are still many areas to study andcertainly we expect to discover great natural resources.
These studies will accelerate the already counted photogrammetric base maps, where the sample observations in the field can directly dial photogrammetric at the rock type, and structural attitude to build later with laboratory studies, local plans and sections once integrated, can form high geological sheets, drawings and lettersgeographical scale.
The surface geological interpretation can build structural contour maps, rhumb lines, structural and stratigraphic unconformities, which mark the folds, faults and surface structural data to interpret what could happen underground.
The aim is to understand the stratigraphy and structure obtained primarily by drilling oil wells or aconíferos purposes,study of wells and boreholes to pass through the layer of weathering. By exploring the subsoil may be extrapolations or interpolations of the superficial surface geology outcrops that are not very distant, if they are of continental origin, or relatively remote distances, if the stratification is continuous and a few changes, such as marine in this case, may draw on seismological studies to ascertainthe depth, attitude and thickness of rocks. The geology of the soil must be performed by specialized technicians, preferably with experience in surface geology and the study will be mainly rock fragments obtained from drilling data, to be identified with respect to color, composition, thickness and be possible to identify and specify the age of them.
Petroleos Mexicanos (PEMEX) has a very fullbody subsurface geologists, the product of the experience of more than 42 years in drilling wells more than 12000, both polling and development, so that the technique used by them is one of the most advanced.
This method should be considered the following:
a) Collect the geological history of the area to study, especially the type of formations and their stratigraphic and structuralrelationships, should familiarize themselves beforehand with the aim of the locations.
b) Describe in detail the channel samples recovered, usually every 5 m, to study the physical characteristics of the rocks (color, hardness, lotólogia, etc.) and fossil content. To this effect should have with a hand, or with low magnification stereo microscope.
Geochemistry is the science ofspace and time, the chemical elements present in the earth's crust, its distribution, order and genetic type of deposit and the balance of its combinations of elements.
The geochemistry encompasses large areas of research, most notably the mining and oil. The purpose of geochemical exploration, especially when it comes to mining is to detect outliers in the mineral content and trace chemicalelements in rocks, sediments, water or vegetation.
These outliers are due to primary or secondary migration of elements that exist in a material creates a geochemical cycle cycle called Hawkes and Webb (1966).
In the lithosphere the geochemical cycle begins with the initial crystallization of magma, continues through the alteration and weathering of rocks and, subsequently, to transportation and...