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Abalos Colles (
The Abalos Colles
File:PSP 006875 2580 RED.NOMAP Abalos Colles.jpg, Top view of one of the Abalos Colles mounds with a cratered top.
File:PSP 006941 2570 RED Chasma Borealis - Southern Abalos Colles Region.jpg, Chasma Borealis - Southern Abalos Colles Region, showing Abalos Colles mounds M4 and M5.
File:ESP 036570 2585 RED Terrain Near Abalos Colles.jpg, Terrain Near Abalos Colles
Abalos Colles (Latin
Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...
for "Abalos Hills") is a stratified
Stratification may refer to:
Mathematics
* Stratification (mathematics), any consistent assignment of numbers to predicate symbols
* Data stratification in statistics
Earth sciences
* Stable and unstable stratification
* Stratification, or st ...
fragment of the Rupes Tenuis basal unit of Planum Boreum, located south of the Rupes Tenuis
Rupes Tenuis ( la, thin cliff) is a Martian north polar scarp. It is named after one of the classical albedo features on Mars. Its name was officially approved by IAU in 1988. It extends from latitude 74.94°N to 82.2°N and from longitude 242 ...
scarp and west of the Escorial crater. It contains 16 mounds. Abalos Colles is one of the named features in the vicinity of Planum Boreum
Planum Boreum (Latin: "the northern plain") is the northern polar plain on Mars. It extends northward from roughly 80°N and is centered at . Surrounding the high polar plain is a flat and featureless lowland plain called Vastitas Borealis which e ...
, the Martian
Mars, the fourth planet from the Sun, has appeared as a setting in works of fiction since at least the mid-1600s. It became the most popular celestial object in fiction in the late 1800s as the Moon was evidently lifeless. At the time, the pred ...
North pole. It is named after one of the classical albedo features on Mars
The classical albedo features of Mars are the light and dark features that can be seen on the planet Mars through an Earth-based telescope. Before the age of space probes, several astronomers created maps of Mars on which they gave names to the fe ...
located at latitude 72°N, longitude 70°W. Its name was officially approved by the International Astronomical Union
The International Astronomical Union (IAU; french: link=yes, Union astronomique internationale, UAI) is a nongovernmental organisation with the objective of advancing astronomy in all aspects, including promoting astronomical research, outreac ...
(IAU) in 2003.
It extends from latitude 74.81°N to 78.78°N and from longitude 284.54°E to 293.39°E (66.61°W – 75.46°W). Its centre is located at latitude 71.65°N, longitude 76.83°W, and has a diameter of 235.83 km. The Abalos Colles mounds are of irregular, angular, or conical form. The tops of the conical forms can feature craters, and can also be flat. Their height varies between less than a hundred to less than 700 metres, with top diameters in the range of 20 km. The northernmost boundary of the dune field of Abalos Undae
Abalos Undae (Latin for "Abalos Waves") is a dune field on Mars in the periphery of Planum Boreum, the Martian North pole. It is one of the officially named northern circumpolar dune fields, along with Olympia, Hyperboreae, and Siton Undae, ...
is located in the southwest channel that separates Abalos Colles from the main ice cap, and from there the dune field extends southwest all the way to the lowlands of Vastitas Borealis
(Latin 'northern waste') is the largest lowland region of Mars. It is in the northerly latitudes of the planet and encircles the northern polar region. Vastitas Borealis is often simply referred to as the northern plains, northern lowlands or ...
.
Formation
The Abalos Colles stratigraphy
Stratigraphy is a branch of geology concerned with the study of rock (geology), rock layers (Stratum, strata) and layering (stratification). It is primarily used in the study of sedimentary rock, sedimentary and layered volcanic rocks.
Stratigrap ...
shows similar characteristics with the
Rupes Tenuis basal unit, and it is considered a remnant of a larger, contiguous ancient north polar basal unit. The Abalos Colles formation is considered to be the result of large-scale erosion episodes of the Rupes Tenuis basal unit. Probable erosion mechanisms include crater impact which formed ejecta
Ejecta (from the Latin: "things thrown out", singular ejectum) are particles ejected from an area. In volcanology, in particular, the term refers to particles including pyroclastic materials (tephra) that came out of a volcanic explosion and magma ...
that subsequently covered and protected the ancient basal unit.
Conical mounds with flat or cratered tops could have been formed by layer accumulations on top of impact craters which then eroded to varying degrees, depending on the size of the original crater. At the southern boundary of Chasma Boreale, a sequence of mounds of Abalos Coles with flat, pitted or cratered tops, show similar morphological characteristics to small Iceland
Iceland ( is, Ísland; ) is a Nordic island country in the North Atlantic Ocean and in the Arctic Ocean. Iceland is the most sparsely populated country in Europe. Iceland's capital and largest city is Reykjavík, which (along with its s ...
ic shield volcano
A shield volcano is a type of volcano named for its low profile, resembling a warrior's shield lying on the ground. It is formed by the eruption of highly fluid (low viscosity) lava, which travels farther and forms thinner flows than the more v ...
es of basalt
Basalt (; ) is an aphanite, aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the planetary surface, surface of a terrestrial ...
ic origin. Adjusted to account for the difference in topology between the two planets, both the terrestrial and Martian volcanoes share similar side slopes and volume to diameter ratios, the latter being defined as the ''volcanic productivity index''.
Images from HiRISE
See also
*Hagal dune field
Hagal is the informal name of a dune field on Mars located below the north pole of Mars. Its name derives from the sand dunes in Frank Herbert's novel ''Dune'' and the fictional planet Hagal. It is located at coordinates 78.0° N latitude, 84.0 ...
* Nili Patera dune field
Nili Patera is a dune field on Mars. It is located on top of a lava bed, at the site of an ancient volcano, the Nili Patera caldera of Syrtis Major, near the Martian equator, and it is one of the most active dune fields of Mars. Its location ...
References
{{Portal bar, Solar System Hills on Mars Mare Boreum quadrangle