Coal Nunatak
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Coal Nunatak () is a flat-topped rock mass with steep cliffs facing south, standing southwest of
Corner Cliffs The Corner Cliffs () are a rocky mass surmounted by two flat-topped summits , immediately south of Saturn Glacier and lying northeast of Coal Nunatak in the southeast part of Alexander Island, Antarctica. The rocks of these cliffs were hidden ...
on the southeast corner of
Alexander Island Alexander Island, which is also known as Alexander I Island, Alexander I Land, Alexander Land, Alexander I Archipelago, and Zemlja Alexandra I, is the largest island of Antarctica. It lies in the Bellingshausen Sea west of Palmer Land, Antarc ...
,
Antarctica Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean, it contains the geographic South Pole. Antarctica is the fifth-largest contine ...
.
Lincoln Ellsworth Lincoln Ellsworth (May 12, 1880 – May 26, 1951) was a polar explorer from the United States and a major benefactor of the American Museum of Natural History. Biography Lincoln Ellsworth was born on May 12, 1880, to James Ellsworth and Eva F ...
first noted it from the air on November 23, 1935, and mapped it from photos obtained on that flight by W.L.G. Joerg. Observed from the northwest (the direction from which Ellsworth photographed this
nunatak A nunatak (from Inuit ''nunataq'') is the summit or ridge of a mountain that protrudes from an ice field or glacier that otherwise covers most of the mountain or ridge. They are also called glacial islands. Examples are natural pyramidal peaks. ...
), only the summit protrudes above the coastal ice, and it was uncertain whether this was a
peak Peak or The Peak may refer to: Basic meanings Geology * Mountain peak ** Pyramidal peak, a mountaintop that has been sculpted by erosion to form a point Mathematics * Peak hour or rush hour, in traffic congestion * Peak (geometry), an (''n''-3)-di ...
on Alexander Island or an island in
George VI Sound George VI Sound or Canal Jorge VI or Canal Presidente Sarmiento or Canal Seaver or King George VI Sound or King George the Sixth Sound is a major bay/ fault depression, 300 miles (483 km) long and mainly covered by a permanent ice shelf. It ...
. Its true nature was determined by the
Falkland Islands Dependencies Survey The British Antarctic Survey (BAS) is the United Kingdom's national polar research institute. It has a dual purpose, to conduct polar science, enabling better understanding of global issues, and to provide an active presence in the Antarctic on ...
(FIDS) who visited and surveyed this nunatak in 1949. So named by FIDS for exposures of thin
lenses A lens is a transmissive optical device which focuses or disperses a light beam by means of refraction. A simple lens consists of a single piece of transparent material, while a compound lens consists of several simple lenses (''elements''), ...
of
coal Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other elements, chiefly hydrogen, sulfur, oxygen, and nitrogen. Coal is formed when dea ...
occur there.Stewart, J., 2011. ''Antarctica: An Encyclopedia,'' 2nd ed. Jefferson, North Carolina and London, McFarland & Company, Inc. 1771 pp.


Middle Cretaceous fossil forests

On the south end and the
summit A summit is a point on a surface that is higher in elevation than all points immediately adjacent to it. The topography, topographic terms acme, apex, peak (mountain peak), and zenith are synonymous. The term (mountain top) is generally used ...
of Coal Nunataka, an extensive mid-
Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of th ...
(
Albian The Albian is both an age of the geologic timescale and a stage in the stratigraphic column. It is the youngest or uppermost subdivision of the Early/Lower Cretaceous Epoch/Series. Its approximate time range is 113.0 ± 1.0 Ma to 100.5 ± 0.9 M ...
)
fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...
forest is exposed on a single bedding plane within the Triton Point Formation of the Fossil Bluff Group. The floor of this fossil forest occurs from the top of the
outcrop An outcrop or rocky outcrop is a visible exposure of bedrock or ancient superficial deposits on the surface of the Earth. Features Outcrops do not cover the majority of the Earth's land surface because in most places the bedrock or superficial ...
and is exposed over an area of about . This fossil forest consists of 54 in situ stumps that vary in diameter from . The stumps are spaced apart. These stumps have eroded out of a layer of coarse, brown,
fluvial In geography and geology, fluvial processes are associated with rivers and streams and the deposits and landforms created by them. When the stream or rivers are associated with glaciers, ice sheets, or ice caps, the term glaciofluvial or fluviog ...
sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates) ...
that contains a large amount of volcanic
sediment Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example, sand an ...
. Where the associated forest floor is covered by white
tuffaceous Tuff is a type of rock made of volcanic ash ejected from a vent during a volcanic eruption. Following ejection and deposition, the ash is lithified into a solid rock. Rock that contains greater than 75% ash is considered tuff, while rock c ...
sandstone, parts of the trunks are totally carbonized. Two other distinct fossil forests with standing trunks are exposed in the cliffs of the south end of Coal Nunatak. Another, less well exposed, fossil forest outcrops on the north end of Coal Nunatak. These fossil forests are associated with
paleosol In the geosciences, paleosol (''palaeosol'' in Great Britain and Australia) is an ancient soil that formed in the past. The precise definition of the term in geology and paleontology is slightly different from its use in soil science. In geolo ...
s and leaf fossils.Jefferson, T.H., 1982. ''Fossil forests from the Lower Cretaceous of Alexander Island, Antarctica.'' ''Palaeontology'', 25, 681–708.Howe, J. and Francis, J.E., 2005. ''Metamorphosed palaeosols associated with Cretaceous fossil forests, Alexander Island, Antarctica.'' ''Journal of the Geological Society,'' 162(6), pp.951–957.


References

Paleontological sites of Antarctica Nunataks of Alexander Island {{AlexanderIsland-geo-stub