Monday, February 13, 2012

First Blog Entry

How Lake Sevan was created...


On a clear and sunny day, the lake amazingly is a deep blue color. A famous writer once said about Lake Sevan, that the waters were like a piece of the sky that had descended to the earth among the mountains. Lake Sevan is known to be one of the highest altitude lakes in the world and is the largest alpine lake in the world. This is a huge mountain lake that is 6200 feet above sea level. 



Also I want to mention the huge mountain line that has been formed throughout years. Compared to the predisturbed state of Lake Sevan, volume, area and depth have all decreased. Prior to disturbance (1930s), Lake Sevan held 58.50 ckm, covered 1,416 sqm, and was on average 41 meters deep and 100 meters at its deepest point. This lake was formed by volcanic activity millions of years ago. Ejected magma left behind a fissure that held water in what is labeled a Maar Lake. So magma heated up groundwater, pressure builds as the water turns to steam, and then the water and preexisting rock is blasted out of the ground to form a tephra cone with gentle slopes. The lava is still active and flows from central and eastern regions causing lava clusters flow into the lake. Explosive eruptions at the region known as a volcanic field were followed by the extrusion of rhyolite obsidian lava domes and flows. This latest activity produced a series of andesitic and basaltic-andesite cinder cones and lava flows.
The huge mountains are formed from thrust faulting. A Fault is a crack and when rocks break and create a momentum or they form some type of tectonic movement. These types of mountains are known as triangular facets, where each triangle represents a fault and those can be both compressed when the land is pushed together and extended when they are being pulled apart.





Images from: www.haykland.com/lakes
www.armeniapedia.org
www.worldlakes.org


No comments:

Post a Comment