Mineralization Associated to Gold

Rich placer deposits is not something that occurs simply by chance. There used to be a lot of mineralization in the Mother Lode for example with rock that decayed rapidly as well as stream patterns that were well developed and this created quite a rich set up for deposits and for the 49ers that flooded in during that time. There is still a good amount of gold to be recovered from the streams in many different places in the world and to this day a lot of prospectors have claimed to have found gold in a lot of the creeks and river beds they have worked on in many different areas that have the right geology. 

The gold that can be found in older placers is in most cases higher quality than those that have their starting place close by and this is probably because of the alloy that is being removed by the action of the water. When there is a good magnitude of gold in a placer deposit, it is the end result of very positive conditions. This will occur in places where there is an extensive measure of mineralization, rapid rock decay, and precisely developed stream prototypes. When all these factors come together at the same time, big gold placers have the chance of becoming formed. The development that takes place is not a complex development; in areas where the gold has set down, the force of the stream is potent enough to carry with it the pieces of gold that had settled.

In the case of small scale mining or prospecting, one of the first things a prospector will need to look into is examining the deposit and observing how much of the vein or outcrop requires sampling. Bear in mind that in most circumstances, an amateur prospector will only be concerned in the vein. It is not frequent for an amateur to open an adit and be concerned about removing a lot of country rock. In most cases the standard amateur will basically take care of cleaning out a vein to a certain depth and in the cases in where the vein is narrow, the sample can be high graded from the vein itself. Doing this kind of high grading is fine, on the other hand if the deposit does require a good amount of mining done on it, this involves having a good amount of country rock mixed with the sample and this way the prospector is able to get an idea of how much the percentage of the general mineralization is. If the vein is very large, it would be a good plan to get hold of a variety of samples along the face of it given that color is in many cases not an hint of some kinds of mineralization.

For those miners that just so happen to come across outcropping quartz that is stained with iron or has fine grain pyrite it is highly suggested to get it assayed. If the miner is located in a region that has small rounded hills around, the miner should test them for mineralization. In addition, brush that is growing on a canyon wall in an area that is barren can be seen, this can also be an pointer of mineralization and special consideration deems being paid attention to in these particular areas.

If the prospect area holds a mixed succession of lower cretaceous sedimentary and volcanic rocks, look into it. Alteration and mineralization takes place for the most part in the sedimentary rocks all along a regional north striking fault system. The sedimentary rocks consist of volcaniclastic siltstones, sandstones, and conglomerates as well as limestones and gypsum beds. In some cases the sedimentary rocks will seem to have been deposited in a relatively small marine basin inside a main volcanic pile. Contact metamorphism effects can sometimes be seen locally in the sedimentary and volcanic rocks. Some prospects have shown an intricate structural history, a number of variation proceedings and assorted kinds of mineralization. Alteration and mineralization are concentrated in most cases in thin beds of siltstone units, nevertheless late epidote dominated calcic alteration can also have an effect on other units too. Sodic alteration distinguished by albitization, sometimes goes along with silica replacement. Potassic alteration characterized by k feldspar may at times not be strong and overprints sodic alteration groups. Sodic and potassic alteration can be overprinted by a complex calcic alteration event that consists of early actinolite-chlorite alteration and later epidote-calcite alteration. Calcic alteration in many cases holds an iron oxide grouping dominated by specular hematite with a smaller amount of mushketovite and magnetite. Chalcopyrite and lesser pyrite are locally intergrown with iron oxides. Iron oxide and sulfide mineralization happens along NNE to NE striking faults and NW striking quartz calcite veins. Important strike alterations along the fault system have to do with better-developed alteration as well as mineralization.