Origin of the Gold Deposits

Introduction

What is a mineral deposit?Is a sector of the cortex result of different geological processes, there has been the concentration of one or more useful substances.

The gold deposits…

Are mineralized geological bodies of which we can cost-effectively extract gold, the same as found, usually as a native metal, forming alloys with copper, silver, osmium, indium and other elements in different proportions.

Different times of gold mineralization

• The geological history of the earth is marked by a number of times of epigenetic gold mineralization, most of which occurred in the Precambrian, followed by other less extensive in the Paleozoic, Mesozoic and Cenozoic. Most of placer gold has occurred in the Tertiary and Quaternary.

Where does the gold found in the deposits

Both gold and other minerals and elements that accompany it come from the rocks that form the outer crust or melts called magma coming from deep within the earth's crust that cooled and formed igneous rocks. These masses magmatic bring gold and other elements, which in optimal conditions and favorable be deposited in the vicinity of the Earth's crust, forming ore bodies of different shapes and dimensions.

The origin of the gold deposits is varied, but the main source is:

HIDROTERMINAL

RESIDUAL

PLEASURES.

HIGH TEMPERATURE FIELDS HIDROTERMINALESThey are mainly linked with very old rocks (granitic and metamorphic Precambrian and Paleozoic). The bodies are the most common mineral veins or lodes of auriferous quartz, are less common in areas cuarcificación or pyritization of schists, irregular shaped bodies or veins.

INTERMEDIATE TEMPERATURE FIELDS HIDROTERMINALESThese deposits, ore bodies are generally well defined veins, where gold is in native form or within sulfides. Minerals conformantes of veins are quartz, carbonates, barite, pyrite, chalcopyrite, sphalerite, galena, gray ores. Deposits of this temperature are the most important, since it has the highest industrial value.

HIDROTERMINALES FIELDS OF LOW TEMPERATURESThese are closely related alpine volcanic activity, and are in the form of veins (stockwork and gold-mine argentífeiras) formed at shallow depths within the volcanic rocks. The mineralization of these deposits is not uniform, being bolsonadas rich and totally impoverished sectors.Its mineralogical content is usually chalcedony, quartz, rhodochrosite, barite, sulfides, minerals flat, essentially native gold-silver.

HIGH TEMPERATURE FIELDS HIDROTERMINALES

INTERMEDIATE TEMPERATURE FIELDS HIDROTERMINALES

HIDROTERMINALES FIELDS OF LOW TEMPERATURES

Hidroterminales Classification according to temperature

KEY FACTORS FOR THE FORMATION OF HYDROTHERMAL DEPOSITS ARE:

Availability of solutions capable of dissolving mineralizing and transporting mineral matter1

2 Presence of openings in the rocks which solutions can be channeled

3 Presence of placement locations for deposition of mineral content

A chemical reaction resulting in the deposition

Sufficient concentration of mineral matter deposited to reach explotables make deposits.

4

5

RESIDUAL DEPOSITS

Gold are those that have occurred in the weathering of hydrothermal deposits of sulfides. These areas are called "iron hat", where gold, as a metal chemically stable and inactive, builds together with iron oxides, carbonates of lead, silver and minerals other side, mainly stable oxides.

Be eluvial, alluvial and marine, of which the largest and most widespread are alluvial placers. These deposits are formed due to the destruction of gold deposits. By weathering processes. Then the larger gold particles are deposited in alluvial deposits near the mine, whereas the finer particles are carried down and deposited downstream together with the sands forming auriferous alluvial sands.

DEPOSITS OF PLEASURES

What shape are the goldfields?

StockworksAre bodies irregular or asymmetrically, where gold is found in numerous intersecting veinlets or disseminated form, usually of considerable size are bodies that are mainly related to volcanic activity. Here gold is very unevenly distributed within the body forming bolsonadas and sterile areas.

Streaks or veins:These tubular bodies where two of its dimensions are large enough along the strike and dip, whereas third is very small relative to the other two, called power.

The gold placers The gold placers are accumulations of sand usually are shaped like elongated halos that form in the course of rivers or on the terraces adjacent to the river also formed in marine beaches. Here the gold occurs as disseminated in the sand, usually in heavy mineral fractions.

Streaks or veins

EN ROSARIO

ESCALONADA

EMBOLSADA

EMPLUMADA

TYPES OF PLEASURESEn función de los distintos fenómenos fisco - químicos que los producen, los placeres se clasifican en

Eluvial

Diluvial

Pro-alluvial

Alluvial

Beach

A. Eluvial pleasures are those which develop from one area or pre-enriched enriched with environmental component climate type. They dominated on the physical chemical phenomena thus resulting effects are distinctly residual.

B. If the material disintegrated, eluvial deposit if one suffers a gravitational displacement, accumulating in some points of a slope, will in a kind of pleasure called diluvial. The origin of these pleasures have a chemical component (eluvial) and a physical component (transport and partly classification).

C. If the accumulations are located at the foot of the slope formed pleasures are called pro-alluvial type and in them the physical component (transporting and sorting) is greater than the chemical component.

D. Clumps, or part of the pleasures eluvial, diluvial and / or pro-alluvial, are remobilized, transported and sorted bywaters, and deposited in rivers (live bed), in its margins and / or terraces, resulting pleasures are called alluvial

E. When the action of the ice to produce these pleasures are referred moraine and fluvioglacial when the component is mixed. In these pleasures the physical component is predominant

Thanks for your attention.