Wednesday, April 21, 2010

Rock Types In Great Basin National Park

Great Basin National Park is located in the southeastern corner of White Pine County in Nevada's north central region. The park geography includes several peaks of ten to thirteen thousand feet in height in the west, Lehman Caves and other caverns in the northeast, and canyons and washes in the southeastern part of the park.


Limestone


Limestone, a sedimentary rock, is located around the base of the mountains in the South Snake Mountain Range of Great Basin National Park. Two of the park's visitor attractions, Lehman Caves and Lexington Arch, are limestone in origin. Lehman Caves were shaped in Pole Canyon Limestone.Lehman Caves Limestone may be seen along the Baker Creek Road.


Marble


The base of the mountains in Great Basin National Park is partially marble, a metamorphic rock formed from limestone, or calcite. The marble in Great Basin National Park is not high grade.


Sandstone


The sandstone which remains in Great Basin National Park was originally deposited by a sea existent during the Cambrian time. Sandstone is a sedimentary rock type. The sandstone may now be found along the decollement, a fault line formed during the Cenozoic Era.


Shale


Some of the shale formed at the same time as the sandstone was not transformed by metamorphic conditions. Shale is a sedimentary type of rock. It is found along the decollement.


Quartzite


This rock type, a metamorphic rock, was formed from underground layers of sandstone. It may be seen in a large band along Wheeler Peak Scenic Drive and on the higher peaks in Great Basin National Park.


Granite


The granite in Great Basin National Park is an igneous rock. The magma was pressed upward and changed the rocks it came into contact with but cooled while yet underground.


Aragonite


This mineral, which forms a characteristic needle-like pattern, is found in Great Basin National Park in Snake Cave. This cave is one of only eight wild caves in the Park which spelunkers may explore by permit. Snake Cave has notable aragonite formations.Aragonite forms under metamorphic conditions.


Moonmilk


Moonmilk is made up of aragonite, calcite, and hydromagnesite which have leached out of water seeping into Lehman Caves. It is found in the Inscription Room and the area of Lehman Caves known as Rocky Road.


Gypsum


The mineral gypsum, or calcium sulfate, is found in a section of Lehman Caves called the Gypsum Annex. This part of Lehman Caves is not on the cave tour.Gypsum is a sedimentary rock. In the Caves, it comes in many tiny, delicate forms from needles to flowers. The mineral is either colorless or white.







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