Conglomerate Ridge () is a ridge, long, located east-southeast of Mount Bursik in the Soholt Peaks,

Heritage Range The Heritage Range is a major mountain range, long and wide, situated southward of Minnesota Glacier and forming the southern half of the Ellsworth Mountains in Antarctica. The range is complex, consisting of scattered ridges and peaks of mod ...

Ellsworth Mountains The Ellsworth Mountains are the highest mountain ranges in Antarctica, forming a long and wide chain of mountains in a north to south configuration on the western margin of the Ronne Ice Shelf in Marie Byrd Land. They are bisected by Minnesota ...

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 ...

. The ridge trends northwest–southeast and rises to about . It was so named from the conglomerate composition of the ridge by Gerald F. Webers, leader of the

United States Antarctic Research Program The United States Antarctic Program (or USAP; formerly known as the United States Antarctic Research Program or USARP and the United States Antarctic Service or USAS) is an organization of the United States government which has presence in the A ...

Ellsworth Mountains Expedition, 1979–80.

Geology

Detailed

geologic map A geologic map or geological map is a special-purpose map made to show various geological features. Rock units or geologic strata are shown by color or symbols. Bedding planes and structural features such as faults, folds, are shown with st ...

sWebers, G.F., Craddock, C., and Splettstoesser, J.F., ''Geology and Paleontology of the Ellsworth Mountains, West Antarctica''. Boulder, Colorado, Geological Society of America Memoir 170. of the Heritage Range shows that Conglomerate Ridge consists of steeply inclined, 55 to 62 degrees,

Cambrian The Cambrian Period ( ; sometimes symbolized C with bar, Ꞓ) was the first geological period of the Paleozoic Era, and of the Phanerozoic Eon. The Cambrian lasted 53.4 million years from the end of the preceding Ediacaran Period 538.8 million ...

metasedimentary In geology, metasedimentary rock is a type of metamorphic rock. Such a rock was first formed through the deposition and solidification of sediment Sediment is a naturally occurring material that is broken down by processes of weathering and er ...

strata In geology and related fields, a stratum ( : strata) is a layer of rock or sediment characterized by certain lithologic properties or attributes that distinguish it from adjacent layers from which it is separated by visible surfaces known as ei ...

. In terms of increasing age, the Cambrian strata includes the Frazier Ridge, Conglomerate Ridge, Drake Icefall, and Union Glacier formations. The Frazier Ridge Formation consists mainly of fine- to medium-grained green

quartzite Quartzite is a hard, non- foliated metamorphic rock which was originally pure quartz sandstone.Essentials of Geology, 3rd Edition, Stephen Marshak, p 182 Sandstone is converted into quartzite through heating and pressure usually related to tect ...

that contains infrequent beds of green

argillite :''"Argillite" may also refer to Argillite, Kentucky.'' Argillite () is a fine-grained sedimentary rock composed predominantly of indurated clay particles. Argillaceous rocks are basically lithified muds and oozes. They contain variable amounts ...

and black

shale Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4) and tiny fragments (silt-sized particles) of other minerals, especial ...

. It is estimated to be at least thick. It is underlain by the of Conglomerate Ridge Formation, which is named for Conglomerate Ridge. It consists of of buff, polymict,

clast Clastic rocks are composed of fragments, or clasts, of pre-existing minerals and rock. A clast is a fragment of geological detritus,Essentials of Geology, 3rd Ed, Stephen Marshak, p. G-3 chunks, and smaller grains of rock broken off other rocks ...

-supported conglomerate with beds of fine- to coarse-grained

and overlying of sheared gray, green, and buff argillaceous quartzite. Underlying the Conglomerate Ridge Formation is of intensively sheared and folded black shale and interlayered

limestone Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms whe ...

of the Drake Icefall Formation. It overlies an unknown thickness of the Union Glacier Formation. The Union Glacier Formation consists of over of dark green

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 ...

diamictite, which contains minor layers of tuffaceous rocks, metamorphosed buff

calcareous Calcareous () is an adjective meaning "mostly or partly composed of calcium carbonate", in other words, containing lime or being chalky. The term is used in a wide variety of scientific disciplines. In zoology ''Calcareous'' is used as an adje ...

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) ...

, and buff calcareous conglomerate.

Trilobite Trilobites (; meaning "three lobes") are extinct marine arthropods that form the class Trilobita. Trilobites form one of the earliest-known groups of arthropods. The first appearance of trilobites in the fossil record defines the base of the At ...

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 ...

s from the Drake Icefall and other formations within the Heritage Group indicate that all of these units accumulated during the Middle Cambrian.Webers, G.F., Bauer, R.L., Anderson, J.M., Buggisch, W., Ojakangas, R.W. and Spörli, K.B., 1992. ''The Heritage Group of the Ellsworth Mountains'', in Webers, G.F., Craddock, C., and Splettstoesser, J.F., ''Geology and Paleontology of the Ellsworth Mountains, West Antarctica''. Boulder, Colorado, Geological Society of America Memoir 170.

References

Ridges of Ellsworth Land {{EllsworthLand-geo-stub