Eberswalde, formerly known as Holden NE, is a partially buried
impact crater
An impact crater is a circular depression in the surface of a solid astronomical object formed by the hypervelocity impact of a smaller object. In contrast to volcanic craters, which result from explosion or internal collapse, impact crater ...
in
Margaritifer Terra
Margaritifer Terra () is an ancient, heavily cratered region of Mars. It is centered just south of the Martian equator at and covers 2600 km at its widest extent. The area reveals "chaos terrain", outflow channels, and alluvial plains that a ...
,
Mars
Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, only being larger than Mercury. In the English language, Mars is named for the Roman god of war. Mars is a terrestrial planet with a thin at ...
. Eberswalde crater lies just to the north of Holden, a large crater that may have been a lake. The 65.3-km-diameter crater, centered at 24°S, 33°W, is named after the
German
German(s) may refer to:
* Germany (of or related to)
** Germania (historical use)
* Germans, citizens of Germany, people of German ancestry, or native speakers of the German language
** For citizens of Germany, see also German nationality law
**Ge ...
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 ...
's rules for
planetary nomenclature
Planetary nomenclature, like terrestrial nomenclature, is a system of uniquely identifying features on the surface of a planet or natural satellite so that the features can be easily located, described, and discussed. Since the invention of the tel ...
. It was one of the final four proposed landing sites for the Mars rover
Mars Science Laboratory
Mars Science Laboratory (MSL) is a robotic space probe mission to Mars launched by NASA on November 26, 2011, which successfully landed ''Curiosity'', a Mars rover, in Gale Crater on August 6, 2012. The overall objectives include investigati ...
mission. This extraterrestrial geological feature lies situated within the
Margaritifer Sinus quadrangle
The Margaritifer Sinus quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey (USGS) Astrogeology Research Program. The Margaritifer Sinus quadrangle is also referred to as MC-19 (Mars Chart-19) ...
(MC-19) region of Mars. Although not chosen, it was considered a potential landing site for the
Mars 2020
Mars 2020 is a Mars rover mission forming part of NASA's Mars Exploration Program that includes the rover '' Perseverance'', the small robotic, coaxial helicopter '' Ingenuity'', and associated delivery vehicles. Mars 2020 was launched from ...
''Perseverance'' rover, and in the second Mars 2020 Landing Site Workshop it survived the cut and was among the top eight sites still in the running.
Landforms in the crater provide strong evidence of the prior existence of flowing water on Mars.
Mars Science Laboratory
Several sites in the
Margaritifer Sinus quadrangle
The Margaritifer Sinus quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey (USGS) Astrogeology Research Program. The Margaritifer Sinus quadrangle is also referred to as MC-19 (Mars Chart-19) ...
have been proposed as areas to send NASA's major Mars rover, the Mars Science Laboratory (MSL). Eberswalde was shortlisted as one of the final four proposed landing sites for the ''Curiosity'' rover, part of the MSL mission. It was voted a close second after
Gale
A gale is a strong wind; the word is typically used as a descriptor in nautical contexts. The U.S. National Weather Service defines a gale as sustained surface winds moving at a speed of between 34 and 47 knots (, or ).MRO discovered iron/magnesium smectites here. This mineral requires water to form.
Eberswalde Delta
The crater contains
inverted relief
Inverted relief, inverted topography, or topographic inversion refers to landscape features that have reversed their elevation relative to other features. It most often occurs when low areas of a landscape become filled with lava or sediment th ...
, an exhumed
delta
Delta commonly refers to:
* Delta (letter) (Δ or δ), a letter of the Greek alphabet
* River delta, at a river mouth
* D ( NATO phonetic alphabet: "Delta")
* Delta Air Lines, US
* Delta variant of SARS-CoV-2 that causes COVID-19
Delta may also ...
formed by the flow of a liquid, most likely water. The series of valleys leading into the delta "
drain
Drain may refer to:
Objects and processes
* Drain (plumbing), a fixture that provides an exit-point for waste water or for water that is to be re-circulated on the side of a road
* Drain (surgery), a tube used to remove pus or other fluids from ...
" an area of approximately 4000 km2. The surface area of the delta is 115 km2, measuring 13 km by 11 km. The delta was discovered from images acquired by the
Mars Global Surveyor
''Mars Global Surveyor'' (MGS) was an American robotic space probe developed by NASA's Jet Propulsion Laboratory and launched November 1996. MGS was a global mapping mission that examined the entire planet, from the ionosphere down through t ...
in 2003, operated
Malin Space Science Systems
Malin Space Science Systems (MSSS) is a San Diego, California-based private technology company that designs, develops, and operates instruments and technical equipment to fly on unmanned spacecraft. MSSS is headed by chief scientist and CEO Mich ...
. Eberswalde delta has six lobes and is about 100 meters thick.
The delta also provides unambiguous evidence that some Martian sedimentary rocks have been deposited in a liquid. The meandering of the channels provides evidence to support this. Additional sediments were deposited on top of the delta, burying it. The deposits in the channels formed sedimentary rock. As the surrounding softer sediments were eroded away, the delta was exhumed, but inverted. Some layers of the delta contain clay. Finding clay is significant because it forms in water with a pH close to neutral. This type of environment would support life, and clay can form well-preserved fossils.
Many craters once contained lakes. The delta in Eberswalde Crater is strong evidence that a lake once existed here.
Based on an estimate by Moore et al. in 2003 of flow volume to the crater at 700 m3/s, it is estimated that it would take twenty years to completely fill the crater, ignoring evaporation and infiltration. However, this is unlikely because it is hypothesized that the delta was not formed in a permanent lake but rather a series of short
lacustrine
A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much larger ...
episodes on the order of years. This suggests that the Martian climate at the
Noachian epoch
The Noachian is a geologic system and early time period on the planet Mars characterized by high rates of meteorite and asteroid impacts and the possible presence of abundant surface water. The absolute age of the Noachian period is uncertai ...
time of formation was characterized by a series of short, wet spells rather than a sustained wet climate.
See also
*
Geography of Mars
Areography, also known as the geography of Mars, is a subfield of planetary science that entails the delineation and characterization of regions on Mars. Areography is mainly focused on what is called physical geography on Earth; that is the di ...
*
Impact crater
An impact crater is a circular depression in the surface of a solid astronomical object formed by the hypervelocity impact of a smaller object. In contrast to volcanic craters, which result from explosion or internal collapse, impact crater ...
Lakes on Mars
In summer 1965, the first close-up images from Mars showed a cratered desert with no signs of water. However, over the decades, as more parts of the planet were imaged with better cameras on more sophisticated satellites, Mars showed evidence o ...
Mars Science Laboratory
Mars Science Laboratory (MSL) is a robotic space probe mission to Mars launched by NASA on November 26, 2011, which successfully landed ''Curiosity'', a Mars rover, in Gale Crater on August 6, 2012. The overall objectives include investigati ...
*
Ore resources on Mars
Mars may contain ores that would be very useful to potential colonists. The abundance of volcanic features together with widespread cratering are strong evidence for a variety of ores. While nothing may be found on Mars that would justify the hi ...
*
Planetary nomenclature
Planetary nomenclature, like terrestrial nomenclature, is a system of uniquely identifying features on the surface of a planet or natural satellite so that the features can be easily located, described, and discussed. Since the invention of the tel ...
*
River delta
A river delta is a landform shaped like a triangle, created by deposition of sediment that is carried by a river and enters slower-moving or stagnant water. This occurs where a river enters an ocean, sea, estuary, lake, reservoir, or (more ra ...
- the terrestrial equivalent
*
Water on Mars
Almost all water on Mars today exists as ice, though it also exists in small quantities as vapor in the atmosphere. What was thought to be low-volume liquid brines in shallow Martian soil, also called recurrent slope lineae, may be grains of ...