Ulysses Colles is an official name for conical edifices associated with flows in
Ulysses Fossae
The Ulysses Fossae are a group of troughs in the Tharsis quadrangle of Mars at 10.06° north latitude and 123.07° west longitude. They were named after an albedo feature name. The area contains pitted cones called Ulysses Colles which were in ...
in the
Tharsis quadrangle
The Tharsis quadrangle is one of a series of 30 list of quadrangles on Mars, quadrangle maps of Mars used by the United States Geological Survey (USGS) Astrogeology Research Program. The Tharsis quadrangle is also referred to as MC-9 (Mars Chart- ...
of
Mars
Mars is the fourth planet from the Sun. It is also known as the "Red Planet", because of its orange-red appearance. Mars is a desert-like rocky planet with a tenuous carbon dioxide () atmosphere. At the average surface level the atmosph ...
.
These conical edifices form small
volcanic field
A volcanic field is an area of Earth's Earth's crust, crust that is prone to localized volcano, volcanic activity. The type and number of volcanoes required to be called a "field" is not well-defined. Volcanic fields usually consist of clusters ...
which were interpreted as result of
explosive eruption
In volcanology, an explosive eruption is a volcanic eruption of the most violent type. A notable example is the 1980 eruption of Mount St. Helens. Such eruptions result when sufficient gas has dissolved under pressure within a Viscosity, viscous ...
s on Mars where martian equivalents to terrestrial
pyroclastic cone
Volcanic cones are among the simplest volcanic landforms. They are built by ejecta from a volcanic vent, piling up around the vent in the shape of a cone with a central crater. Volcanic cones are of different types, depending upon the nature and s ...
s,
cinder cone
A cinder cone or scoria cone is a steep, volcanic cone, conical landform of loose pyroclastic rock, pyroclastic fragments, such as volcanic ash, clinkers, or scoria that has been built around a volcanic vent. The pyroclastic fragments are forme ...
s respectively, exist.
This field is situated north of the
shield volcano
A shield volcano is a type of volcano named for its low profile, resembling a 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 viscous lava ...
es
Biblis Patera
Biblis Tholus is an extinct Martian volcano located at , one of two volcanoes near the center of the Tharsis volcanism. Along with Ulysses Tholus, it is almost midway between Olympus Mons and the Tharsis Montes. Biblis Tholus lies in the Thars ...
and
Ulysses Patera and it is superposed on an old, elevated window of fractured crust of
Ulysses Fossae
The Ulysses Fossae are a group of troughs in the Tharsis quadrangle of Mars at 10.06° north latitude and 123.07° west longitude. They were named after an albedo feature name. The area contains pitted cones called Ulysses Colles which were in ...
, probably of early
Hesperian
The Hesperian is a system (stratigraphy), geologic system and geologic timescale, time period on the planet Mars characterized by widespread Volcanology of Mars, volcanic activity and catastrophic flooding that carved immense outflow channels acr ...
age, which survived flooding by younger
lava flow
Lava is molten or partially molten rock (magma) that has been expelled from the interior of a terrestrial planet (such as Earth) or a Natural satellite, moon onto its surface. Lava may be erupted at a volcano or through a Fissure vent, fractu ...
s associated with plain-style volcanism in Tharsis.
The cones of Ulysses Colles are spread over an area of about 50 to 80 km and their spatial distribution seem to be controlled by N- to NNW-trending
normal fault
In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth's crust result from the action of plate tectonic ...
s. The distribution is not random, more cones are located in the southern part, where are forming clusters of overlapping cones. Also, the southern cones seem to be more preserved than northern cones.
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]
Gallery
File:Ulysses Colles on Mars based on CTX close up.png, Close up view to small conical structures in Ulysses Colles
File:Ulysses Colles on Mars based on CTX close up (2).png, Another view
References
Tharsis quadrangle
Volcanoes of Mars
Cinder cones
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