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Showing posts with label cretaceous. Show all posts
Showing posts with label cretaceous. Show all posts

Friday, July 13, 2012

The Geology of Gulag Gold


Gold mining prisoners in the Kolyma Basin.  They are mining placer gold that is found throughout the area.


The Gulag Ore Field or more correctly the Ducat gold/silver deposit that is located in the central part of the Balygychan-Sugoi trough that is a graben shaped depression that is located near the town of Omsukchan, Kolyma that adjoins to its north the Okhotsk – Chukota a marginal continental volcanic belt.

The deposits of gold are centered on a Cretaceous (ca. 120 million year old) volcanic dome consisting of ultra-potassic rhyolites, ignimbrites and tuff that are interlayered with black argillites.  The whole volcanic complex is intruded at depth by a late Cretaceous (ca. 85 million year old) granite that is from 1,200 – 1,300 meters below the surface.

More gold miners at work in the Kolyma Basin


There were pulses of igneous activity that caused hydrothermal activity to occur in the dome that involved large quantities of fractured, porous and highly permeable Cretaceous rhyolite sills and other steeply dipping subvolcanic bodies to be affected covering an area that covered more then 25 square kilometers.

Most of the known mineralization was later to the younger intrusion that includes tin bearing greisen-type that occurs in the contact zones of the granitic plutons. They ore deposits himself were located at a considerable distance from the granite.

Part of the Kolyma Basin is within the Arctic Circle giving it a sub-Arctic climate having very cold winters that can last for up to six months. Most of the area is covered with permafrost and tundra. During the winter temperatures range from -19°C to -38°C with even lower temperatures found in the interior. Besides gold there are also rich reserves of silver, 10, tungsten, mercury, antimony, coal, oil and peat. It has been estimated that the area contains in addition to gold 1.2 billion tons of oil and one point 5,000,000,000 m³ of gas.

This is the area whose mineral wealth was discovered by Yuri Bilibin in the 1920s that was quickly developed into the infamous Gulag prison camps by Stalin in the 1930s. There was also the area Bilibin used as the model for his theory of Metallogeny and Global Tectonics that has gained much traction sense of the world of geology.

Development began in 1932 and of Joseph Stalin the Kolyma Basin became the most notorious place for the Gulag labor camps. It has been estimated that over 1 million people died en route to the area or in the Kolyma’s between from 1932 until 1954. It was Kolyma’s reputation that caused Aleksandr Solzhenitsyn ferrite his famous book the Gulag Archipelago. In this book Solzhenitsyn came to characterize it as the “pole cold and cruelty.”

Gold and platinum were found in the Kolyma during the time when industrialization began in the USSR under Stalin’s First Five Year Plan in a period when the need for capital that would finance this economic development.  The Kolyma Basin gold was a perfect fit and development of the basin began in 1932 based on prisoner labor. 

In 1932 construction began on Kolyma Highway into the interior those that become known as the Road of Bones because of the number of people in Paris in its construction. This role eventually came to serve 80 different camps that were not have around the region of the uninhabited taiga. The first director of the Kolyma camps was Eduard Berzin who was the Cheka officer that was removed in 1937 and shot during the period of great purges of the USSR.

Far Eastern Russia geologically is North American plate that also includes Kamchatka Peninsula in northern Hokkaido Island of Japan. This being so it is probable that the gold deposits of this part of Siberia are closely related to those found in the Tintina gold belt of Alaska. It also indicates that most landmasses on Earth are really just one supercontinent with the sole exception being Antarctica.

Wednesday, March 7, 2012

Gold Occurrences in Haiti


Coat of Arms of Haiti


When he was asked to describe what kind of land was to be found in Haiti Christopher Columbus picked up a piece of paper crumpled it and dropped it on the table. This was the kind of land they had in Haiti he told them it is extremely mountainous as well as the land in the Dominican Republic where just over the border from Haiti they actually have mountain peaks that are more than 10,000 feet high. The Gold occurrences in Haiti have been mainly discovered in the northern mountains of not only Haiti but the entire island of Hispaniola that also includes the Dominican Republic.

The rocks and the entire island of Hispaniola are no older than the Cretaceous Period although on and off laying island from the main island there are some rocks that are arguably from the Paleozoic era.  First gold mines on the island were established by the Spaniards in 1520. It was these gold mines that led to the extinction of the Arawak Indians on the island because the Spaniards used them as slaves to work the mines. The very name Haiti is one of the few words that have survived the Arawak Indians, it means mountainous place.

Once the Spaniards discovered the tremendous amounts of gold to be had in Mexico Gold mining operations in Haiti came to an ending and for centuries Gold Mining almost ceased on the island. Gold was recently rediscovered in Haiti along with other base metals in booting copper and zinc. These deposits are now being explored by many prospectors and mining companies from the US and Canada.

Since the gold mining industry has reestablished itself in Haiti there has been a growth of artisanal mining throughout the country. And there are gold buyers that make you regular circuit of the country buying gold from the miners in what has been described as a circus atmosphere somewhat reminiscent of a flea market. There are many places where gold has been found in hard rock deposits, but there are many places where it can also be found as placer gold.

One of these deposits located at Grand Bois is estimated to contain over 4,000,000 tonnes of ore that averages 1.9 g per tonne. The gold is found in the oxidized zone near the surface of the earth making it extremely amenable to open pit mining. There are other deposits of gold found throughout the northern part of the island, but Grand Bois is the largest. Most of the gold of his been discovered is in the vicinity of where two fault lines intersect. Copper is another metal that his been found on the island in considerable amount that may prove to be more monetarily rewarding then the gold deposits.