Surface features of Venus

Last updated November 28, 2023

Global radar map of the surface of Venus VenusDonMiguel.gif — Global radar map of the surface of Venus

The surface of Venus is dominated by geologic features that include volcanoes, large impact craters, and aeolian erosion and sedimentation landforms. Venus has a topography reflecting its single, strong crustal plate, with a unimodal elevation distribution (over 90% of the surface lies within an elevation of -1.0 and 2.5 km)^[1] that preserves geologic structures for long periods of time. Studies of the Venusian surface are based on imaging, radar, and altimetry data collected from several exploratory space probes, particularly Magellan , since 1961 (see Venus Exploration). Despite its similarities to Earth in size, mass, density, and possibly composition, Venus has a unique geology that is unlike Earth's. Although much older than Earth's, the surface of Venus is relatively young compared to other terrestrial planets (<500 million years old), possibly due to a global-scale resurfacing event that buried much of the previous rock record.^[2] Venus is believed to have approximately the same bulk elemental composition as Earth, due to the physical similarities, but the exact composition is unknown. The surface conditions on Venus are more extreme than on Earth, with temperatures ranging from 453 to 473 °C and pressures of 95 bar.^[3] Venus lacks water, which makes crustal rock stronger and helps preserve surface features. The features observed provide evidence for the geological processes at work. Twenty feature types have been categorized thus far. These classes include local features, such as craters, coronae, and undae, as well as regional-scale features, such as planitiae, plana, and tesserae.^[4]

Plains

Plains are large areas of relatively flat topography on Venus that form at varying elevations. Plains with elevations within 1–3 km of the datum are referred to as lowland plans, or planitiae, and those above are named highland plains, or plana.^[4] Plains cover 80% of the Venusian surface, and, unlike those seen on other silicate planets, are heavily faulted or fractured throughout. Structurally, these plains contain features such as wrinkle ridges, grabens (fossa and linea), fractures, scarps (rupes), troughs, hills (collis), and dikes in both local and region scales.^[5] Plains often contain visible flow patterns, indicating a source from volcanic lava flows. The more pronounced lave flow fields are named fluctūs. The presence of surface flow patterns, in conjunction with crosscutting valleys, has given rise to the hypothesis that these plains likely formed by global lava flows over a short timescale and were subsequently exposed to compressional and extensional stresses.^[6] Structurally, plains are often deformed in belts of ridges (dorsa) or fractures (lineae) of various orientation and morphology.

Channels/valles

The surface of Venus contains over 200 channel systems and named valles, that resemble terrestrial rivers. These channels vary in length and width and are commonly found in planar regions of the planet. Channel length and width ranges from the minimum resolution of Magellan imaging to over 6800 km long (Baltis Vallis) and up to 30 km wide. Their global distribution is not uniform, and tend to concentrate around the equatorial region, near volcanic structures. Venusian valles also show characteristics of flows, such as levees on the margins and downstream narrowing and shallowing. Channels also do not contain tributaries, despite their large scale. However, because of the high surface temperature of Venus, liquid water is unstable, making their comparison with terrestrial rivers difficult. These features are similar to lava flows on other terrestrial planets, which has led to the conclusion that these valleys likely formed from volcanic flows. This is also suggested by the evidence of cooled lava flows filling the valles.^[7] Channels likely formed in very short timescales (1–100 years), indicating very fast movement and erosion of lavas.^[6]Venusian channels are classified by morphology and include three types: simple, complex, and compound.^[8]

Simple channels are single channel valleys with little to no branching or anastomosing. Types of simple channels observed on Venus include sinuous rilles, simple channels with flow margins, and canali. Sinuous rilles are like those seen on the Moon; narrow erosive channels that originate from regions of volcanic collapse, such as coronae. Simple channels with flow margin are located in obvious flow fields, have an undefined source and end, and are believed to feed into large flows from surrounding volcanics. Canali, like the Baltis Vallis, are long flows with constant width and depth that may contain abandoned channels, bends, and levees, indicating they are sourced from large amounts of thick lavas.^[7]^[8]
Complex channels are channels that can be braided, anastomosing, or in distributary patterns. They commonly form on lava flow deposits, but also occur elsewhere. Complex channels without flow margins may form part of a larger flow system, and form as channels of lava flows erode into the crust. Complex channels with flow margins appear as non-erosional, and their individual channels are separated by islands of crust of differing radar qualities.^[7]^[8]
Compound channels show simple and complex channel structures. These channels usually begin as simple channels and bifurcate and meander as flow energy decreases on its distal reaches.^[7]^[8]

Volcanism

Volcanic centers

Over 1,100 volcanic structures over 20 km in diameter have been identified on Venus, and it is assumed that smaller structures probably number many times these. These structures include large volcanic edifices, shield volcano fields, and individual calderas. Each of these structures represents a center of extrusive magma eruption and differences in amount of magma released, depth of the magma chamber, and rate of magma replenishment effect volcano morphology. When compared to Earth, the number of preserved volcanic zones is staggering, and this is based on Venus' strong crust due to a lack of water. Volcanic centers on Venus are not distributed evenly, as over half of the centers are found in and around the Beta-Atla-Themis region, which covers <30% of the planet's surface. These tend to occur in mid to upper altitudes, where rifting and extension are common, and they signal mantle upwellings to the surface.^[9] Volcanic centers on Venus are characterized in two main categories based on the ability or inability to create a shallow magma reservoir: Large flows originating from a single edifice or extensive regions with many small eruption sites clustered together.^[10]

Single volcanoes denote a single, large edifice. Volcanoes of this type include large volcanoes (>100 km in diameter, often named mons, examples: Theia Mons and Maat Mons), intermediate volcanoes (20–100 km in diameter), and calderas. These single-eruption-center volcanoes are sustained by a shallow magma chamber in the crust. The magma chamber is replenished by magma from mantle upwelling and decompression melting, causing pooling and trapping of a reservoir. The trapping of a magma chamber allows long-term eruption, and results in magma flows that may create large volcanic domes and flow deposits. The extrusion of magma to the surface is often linked to rifting or extensional tectonics in the region, and the shape of the dome or magma flow field is determined by the chemistry and viscosity of the magma. Each of these types of volcanoes can further be described based on the shape of the dome created, number of edifices present, presence of rifting along the dome, radial fracturing, or collapse of the magma chamber. Intermediate volcanoes with domical surface cones are named tholus, and pancake-shaped volcanoes are named farrum.^[4] Calderas are circular depressions on the surface believed to have formed by deformation above a cooling magma chamber. Calderas on Venus are characterized as simple, single depressions, called coronae, and complex, radially fractured zones, called arachnoids . Some caldera are named patera.^[10]
Shield field are regions 100–200 km in diameter that contain many small, mostly shield, volcanoes (<20 km). Such fields may have tens to hundreds of shield volcanoes. Rarely, individual shield volcanoes will be named colles.^[4] These fields form in areas where the magma replenishment rate is too low to produce a magma reservoir in the crust, resulting in several small eruptions on a regional scale. The dominance of shield-type volcanoes in these regions has led to the name shield fields.^[10]

Coronae

Coronae are large, circular structures with concentric fractures around them that result from mantle upwelling followed by extensional collapse. Since many sequences of upwelling and collapse have been observed as structurally different coronae on Venus' surface, all coronae appear to share a sequence of heavy volcanism as a result of upwelling, topographic rise, tectonic deformation, subsidence due to gravitational collapse, and continued volcanism. Coronae on Venus differ in the location of topographic uplift, and have been characterized as such. Topographic uplift may occur in the depression, the rim, the outer rim, or a combination of these locations. A collapsing coronae coupled with extensional stressing may result in rifting, creating a chasmata region.^[9]^[11]

Large lava flow fields

Large lava flow fields are described as flood-type lava that can be seen in fluctus fields. These are regions flooded with many low-viscosity volcanic flows from a single source that covers the area in a continuous flow field. Some flows may be radially distributed around a volcano of coronae as an apron, be fan-shaped, or sub-parallel in their orientation. Large flow fields may be sourced from large volcanoes, calderas, rift structures, or shield volcano fields and they are often associated with extensional environments.^[9]^[10]

Topographic rises

Topographic rises are domal-shaped areas of high topography that result from both volcanic and tectonic processes. These areas range from 1–4 km above the datum and 1,000–3,000 km across.^[9]^[10] These rises are associated with high-density anomalies, which indicate a source from mantle plumes beneath the crust that warp and uplift the region. Of the topographic rises on Venus, three types have been identified based on their dominating tectonic or volcanic morphology: volcano dominated, rift dominated, and corona dominated. Volcano-dominated rises, such as the Bell Regio, have volcanoes atop the topographic rise. Rift-dominated rises are uplifted by rifting and thinning of the lithosphere and include the Beta Regio and the overlying Theia Mons. In a coronae-dominated rise, uplift is caused by the gravitational collapse and extension of a magma chamber, and include the Themis Regio.^[9]

Tesserae

Tesserae are a feature unique to Venus and are characterized as continent-sized regions of high topography (1 to >5 km above the datum) that are heavily deformed, often with complex patterns of ridges. These areas are formed by the intersection of at least two structural components. Tesserae are classified based on their structural components. Types of Tesserae^[12] Examples include Ishtar Terra and Aphrodite Terra. Tesserae are considered to be the oldest surface features on Venus because of their extensive deformation, and may reflect conditions on Venus before a global resurfacing event.^[12] Some of the ridges found on tesserae terrains, particularly in Ishtar Terra, form large mountain (or mons ) belts. Along the equatorial and southern latitudes, tesserae are labeled regiones, while those in northern latitudes are labeled tessera.^[4]

Impact craters

Impact craters are roughly circular shaped depressions in the surface of a planet due to high velocity impacts with extraterrestrial bodies. The surface of Venus contains almost 1000 impact craters. However, unlike some planets in our system, Venus' thick atmosphere creates a strong shield that decelerates, flattens, and can fracture incoming projectiles. The Venusian surface is devoid of small craters (≤30–50 km in size) because of the effect the atmosphere has on small bodies. Depending on the angle of impact, velocity, size, and strength of the approaching body, the atmosphere may tear and crush the projectile, essentially melting it in the air. This is an important observation for studies of the surface of Venus, as crater are used to determine relative ages and to approximate absolute ages of surface features.^[13]

Craters on Venus are kept in pristine condition, thus making their classification and impact mechanics easy to interpret. Small projectiles burn up in the atmosphere, and those that make it to the surface break into smaller pieces, creating clusters of impact craters similar in appearance to circular lunar craters. As crater size increases, the chance of breakup in the atmosphere decreases and the impact craters become more circular with central peaks from isostatic rebound of the crust. The atmosphere can flatten and slow larger meteoroids to terminal velocity and cause them to explode on impact or near the surface, showering the region in debris. The shockwave from these explosions can flatten the surrounding area for several kilometers. Large impacts create parabolic excavation cones and flows of lava-like debris.^[14]

Aeolian structures

Recent Magellan images show over 6,000 aeolian landforms, including dunes (or undae), windstreaks, and yardangs. Undae and yardangs have direct analogues on Earth and the process that creates them here can be applied to those seen on Venus. Large dune fields have been identified on the surface and the dunes range in size from meters to hundreds of meters. Similarly, yardang fields may exist in locations such as Mead crater.^[4] Windstreaks are parallel linear streaks that form as prevailing winds erode the surface geology. These features illustrate the erosive effect the atmosphere has on the surface of Venus.^[15]

Related Research Articles

Olympus Mons is a large shield volcano on Mars. It is over 21.9 km high, as measured by the Mars Orbiter Laser Altimeter (MOLA), and is about two and a half times Mount Everest's height above sea level. It is one of Mars's largest volcanoes, its tallest planetary mountain, and is approximately tied with Rheasilvia as the tallest mountain currently discovered in the Solar System. It is associated with the Tharsis Montes, a large volcanic region on Mars. It last erupted 25 million years ago.

A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface.

Landforms are categorized by characteristic physical attributes such as their creating process, shape, elevation, slope, orientation, rock exposure, and soil type.

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 lava, which travels farther and forms thinner flows than the more viscous lava erupted from a stratovolcano. Repeated eruptions result in the steady accumulation of broad sheets of lava, building up the shield volcano's distinctive form.

Ascraeus Mons is a large shield volcano located in the Tharsis region of the planet Mars. It is the northernmost and tallest of three shield volcanoes collectively known as the Tharsis Montes.

Alba Mons is a volcano located in the northern Tharsis region of the planet Mars. It is the biggest volcano on Mars in terms of surface area, with volcanic flow fields that extend for at least 1,350 km (840 mi) from its summit. Although the volcano has a span comparable to that of the United States, it reaches an elevation of only 6.8 km (22,000 ft) at its highest point. This is about one-third the height of Olympus Mons, the tallest volcano on the planet. The flanks of Alba Mons have very gentle slopes. The average slope along the volcano's northern flank is 0.5°, which is over five times lower than the slopes on the other large Tharsis volcanoes. In broad profile, Alba Mons resembles a vast but barely raised welt on the planet's surface. It is a unique volcanic structure with no counterpart on Earth or elsewhere on Mars.

Maat Mons is a massive shield volcano on the planet Venus and the planet's second-highest mountain and highest volcano. It rises 8 kilometres (5.0 mi) above the mean planetary radius at 0.5°N 194.6°E, and nearly 5 km above the surrounding plains. It is named after the Egyptian goddess of truth and justice, Ma'at.

<span class="mw-page-title-main">Geology of Venus</span> Geological structure and composition of the second planet from the Sun

The geology of Venus is the scientific study of the surface, crust, and interior of the planet Venus. Of all the other planets in the Solar System, it is the one nearest to Earth and most like it in terms of mass, but has no magnetic field or recognizable plate tectonic system. Much of the ground surface is exposed volcanic bedrock, some with thin and patchy layers of soil covering, in marked contrast with Earth, the Moon, and Mars. Some impact craters are present, but Venus is similar to Earth in that there are fewer craters than on the other rocky planets that are largely covered by them. This is due in part to the thickness of the Venusian atmosphere disrupting small impactors before they strike the ground, but the paucity of large craters may be due to volcanic re-surfacing, possibly of a catastrophic nature. Volcanism appears to be the dominant agent of geological change on Venus. Some of the volcanic landforms appear to be unique to the planet. There are shield and composite volcanoes similar to those found on Earth. Given that Venus has approximately the same size, density, and composition as Earth, it is plausible that volcanism may be continuing on the planet today, as demonstrated by recent studies.

Cleopatra, initially called Cleopatra Patera, is an impact crater on Venus, in Maxwell Montes.

A pancake dome is an unusual type of lava dome found on the planet Venus. They are widely scattered on that planet and often form groups or clusters, though with smaller numbers of pancake domes in each group than is typical for the more common shield volcanos. They are commonly found near coronae and tesserae in the lowland plains. Pancake domes are between 10 and 100 times larger than volcanic domes formed on Earth.

The surface of Venus is dominated by volcanic features and has more volcanoes than any other planet in the Solar System. It has a surface that is 90% basalt, and about 65% of the planet consists of a mosaic of volcanic lava plains, indicating that volcanism played a major role in shaping its surface. There are more than 1,000 volcanic structures and possible periodic resurfacing of Venus by floods of lava. The planet may have had a major global resurfacing event about 500 million years ago, from what scientists can tell from the density of impact craters on the surface. Venus has an atmosphere rich in carbon dioxide, with a density that is 90 times that of Earth's atmosphere.

Volcanic activity, or volcanism, has played a significant role in the geologic evolution of Mars. Scientists have known since the Mariner 9 mission in 1972 that volcanic features cover large portions of the Martian surface. These features include extensive lava flows, vast lava plains, and the largest known volcanoes in the Solar System. Martian volcanic features range in age from Noachian to late Amazonian, indicating that the planet has been volcanically active throughout its history, and some speculate it probably still is so today. Both Earth and Mars are large, differentiated planets built from similar chondritic materials. Many of the same magmatic processes that occur on Earth also occurred on Mars, and both planets are similar enough compositionally that the same names can be applied to their igneous rocks and minerals.

Aden Crater is a small shield volcano located in Doña Ana County, about 25 miles (40 km) southwest of Las Cruces, New Mexico. It is located in the northwest part of the Aden-Afton basalt field, which is part of the central area of the Potrillo volcanic field.

Guinevere Planitia is an expansive lowland region of Venus that lies east of Beta Regio and west of Eistla Regio. These low-lying plains, particularly in the western portion, are characterized by apparent volcanic source vents and broad regions of bright, dark, and mottled deposits. They are the only break in an equatorially connected zone of highlands and tectonic zones. The types, numbers, and patterns of mapped tectonic features and small volcanic landforms in the region provide important detail in the interpretation and evolution of venusian landscape.

NASA's Magellan spacecraft mission discovered that Venus has a geologically young surface with a relatively uniform age of 500±200 Ma. The age of Venus was revealed by the observation of over 900 impact craters on the surface of the planet. These impact craters are nearly uniformly distributed over the surface of Venus and less than 10% have been modified by plains of volcanism or deformation. These observations indicate that a catastrophic resurfacing event took place on Venus around 500 Ma, and was followed by a dramatic decline in resurfacing rate. The radar images from the Magellan missions revealed that the terrestrial style of plate tectonics is not active on Venus and the surface appears to be immobile at the present time. Despite these surface observations, there are numerous surface features that indicate an actively convecting interior. The Soviet Venera landings revealed that the surface of Venus is essentially basaltic in composition based on geochemical measurements and morphology of volcanic flows. The surface of Venus is dominated by patterns of basaltic volcanism, and by compressional and extensional tectonic deformation, such as the highly deformed tesserae terrain and the pancake like volcano-tectonic features known as coronae. The planet's surface can be broadly characterized by its low lying plains, which cover about 80% of the surface, 'continental' plateaus and volcanic swells. There is also an abundance of small and large shield volcanoes distributed over the planet's surface. Based on its surface features, it appears that Venus is tectonically and convectively alive but has a lithosphere that is static.

<span class="mw-page-title-main">Irnini Mons</span> Mountain on Venus

Irnini Mons is a volcanic structure on the planet Venus, and is named after the Assyro-Babylonian goddess of cedar-tree mountains. It has a diameter of 475 km (295 mi), a height of 1.75 km (1.09 mi), and is located in Venus' northern hemisphere. More specifically, it is located in the central Eistla Regio region at in the V-20 quadrangle. Sappho Patera, a 225 km (140 mi) diameter wide, caldera-like, depression tops the summit of Irnini Mons. The primary structural features surrounding Irnini Mons are graben, seen as linear depressed sections of rock, radiating from the central magma chamber. Also, concentric, circular ridges and graben outline the Sappho Patera depression at the summit. The volcano is crossed by various rift zones, including the north-south trending Badb Linea rift, the Guor Linea rift extending to the northwest, and the Virtus Linea rift continuing to the southeast.

Lada Terra is a major landmass near the south pole of Venus which is centered at 60°S and 20°E and has a diameter of 8,615 kilometres (5,353 mi). It is defined by the International Astronomical Union as one of the three "major landmasses," or terrae, of Venus. The term "landmass" is not analogous to the landmass on Earth, as there are no apparent oceans on Venus. The term here applies to a substantial portion of land that lies above the average planetary radius, and corresponds to highlands.

The mapping of Venus refers to the process and results of human description of the geological features of the planet Venus. It involves surface radar images of Venus, construction of geological maps, and the identification of stratigraphic units, volumes of rock with a similar age.

<span class="mw-page-title-main">Volcanism on the Moon</span> Volcanic processes and landforms on the Moon

Volcanism on the Moon is represented by the presence of volcanoes, pyroclastic deposits and vast lava plains on the lunar surface. The volcanoes are typically in the form of small domes and cones that form large volcanic complexes and isolated edifices. Calderas, large-scale collapse features generally formed late in a volcanic eruptive episode, are exceptionally rare on the Moon. Lunar pyroclastic deposits are the result of lava fountain eruptions from volatile-laden basaltic magmas rapidly ascending from deep mantle sources and erupting as a spray of magma, forming tiny glass beads. However, pyroclastic deposits formed by less common non-basaltic explosive eruptions are also thought to exist on the Moon. Lunar lava plains cover large swaths of the Moon's surface and consist mainly of voluminous basaltic flows. They contain a number of volcanic features related to the cooling of lava, including lava tubes, rilles and wrinkle ridges.

References

↑ Ford, P.G.; Pettengill, G.H. (Aug 25, 1992). "Venus topography and kilometer-scale slopes". Journal of Geophysical Research: Planets. 97 (E8): 13103–13114. Bibcode:1992JGR....9713103F. doi:10.1029/92JE01085.
↑ Basilevsky, A.T.; Head, J.W.; Schaber, G.G.; Strom, R.G. (1997). The resurfacing history of Venus (in Venus II, eds. Bougher, S.W. et al.). The University of Arizona Press. pp. 1047–1084. ISBN 0816518300.
↑ Taylor, S.R.; McLennan, S.M (2010). Planetary Crusts: Their composition, origin, and evolution. The Cambridge University Press. pp. 181–206. ISBN 9780521841863.
1 2 3 4 5 6 Tanaka, K.L.; Senske, D.A.; Price, M.; Kirk, R.L. (1997). "Physiography, geomorphic/geologic mapping, and stratigraphy of Venus" (in Venus II, eds. Bougher, S.W. et al.). The University of Arizona Press. pp. 667–694. ISBN 0816518300.
↑ Banerdt, W.B.; McGill, G.E.; Zuber, M.T. (1997). Plains Tectonics on Venus (in Venus II, eds. Bougher, S.W. et al.). The University of Arizona Press. pp. 901–930. ISBN 0816518300.
1 2 Basilevsky, A.T.; Head, J.W. (June 1, 1996). "Evidence for rapid and widespread emplacement of volcanic plains on Venus: Stratigraphic studies in the Baltis Vallis region". Geophysical Research Letters. 23 (12): 1497–1500. Bibcode:1996GeoRL..23.1497B. doi:10.1029/96GL00975.
1 2 3 4 Baker, V.R.; Komatsu, G.; Parker, T.J.; Gulick, V.C.; Kargel, J.S.; Lewis, J.S. (Aug 25, 1992). "Channels and Valleys on Venus: Preliminary Analysis of Magellan Data". Journal of Geophysical Research. 97 (E8): 13, 421–13, 444. Bibcode:1992JGR....9713421B. doi:10.1029/92JE00927.
1 2 3 4 Baker, V.R.; Komatsu, G.; Gulick, V.C.; Parker, T.M. (1997). Channels and Valleys (in Venus II, eds. Bougher, S.W. et al.). The University of Arizona Press. pp. 757–793. ISBN 0816518300.
1 2 3 4 5 Stofan, E.R.; Smrekar, S.E. (2005). "Large topographic rises, coronae, large flow fields, and large volcanoes on Venus: Evidence for mantle plumes?". Geological Society of America Special Paper. 388: 841–861. doi:10.1130/2005.2388(47).
1 2 3 4 5 Crumpler, L.S.; Aubele, J.C.; Senske, D.A.; Keddie, S.T.; Magee, K.P.; Head, J.W. (1997). Volcanoes and centers of volcanism on Venus (in Venus II, eds. Bougher, S.W. et al.). The University of Arizona Press. pp. 697–756. ISBN 0816518300.
↑ Stofan, E.R.; Hamilton, V.E.; Janes, D.M; Smrekar, S.E. (1997). Coronae on Venus: Morphology and origin (in Venus II, eds. Bougher, S.W. et al.). The University of Arizona Press. pp. 931–965. ISBN 0816518300.
1 2 Hansen, V.L.; Willis, J.J.; Banerdt, W.B. (1997). "Tectonic overview and synthesis" (in Venus II, eds. Bougher, S.W.). The University of Arizona Press. pp. 797–844. ISBN 0816518300.
↑ McKinnon, W.B.; Zahnle, K.J.; Ivanov, B.A.; Melosh, H.J. (1997). Cratering on Venus: Models and observations (in Venus II, eds. Bougher, S.W. et al.). The University of Arizona Press. pp. 969–1014. ISBN 0816518300.
↑ Herrick, R.R.; Sharpton, V.L.; Malin, M.C.; Lyons, S.N.; Feely, K. (1997). Morphology and morphometry of impact craters (in Venus II, eds. Bougher, S.W. et al.). The University of Arizona Press. pp. 1015–1046. ISBN 0816518300.
↑ Greenley, R.; Bender, K.C.; Saunders, R.S.; Schubert, G.; Weitz, C.M. (1997). Aeolian processes and features on Venus (in Venus II, eds. Bougher, S.W. et al.). The University of Arizona Press. pp. 547–589. ISBN 0816518300.

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[Ford_and_Pettengill_1992-1] Ford, P.G.; Pettengill, G.H. (Aug 25, 1992). "Venus topography and kilometer-scale slopes". Journal of Geophysical Research: Planets. 97 (E8): 13103–13114. Bibcode:1992JGR....9713103F. doi:10.1029/92JE01085.

[Basilevsky_etal_1997_(resurfacing)_Venus_II-2] Basilevsky, A.T.; Head, J.W.; Schaber, G.G.; Strom, R.G. (1997). The resurfacing history of Venus (in Venus II, eds. Bougher, S.W. et al.). The University of Arizona Press. pp. 1047–1084. ISBN 0816518300.

[Planetary_Crusts-3] Taylor, S.R.; McLennan, S.M (2010). Planetary Crusts: Their composition, origin, and evolution. The Cambridge University Press. pp. 181–206. ISBN 9780521841863.

[Tanaka_etal,_Venus_II-4] 1 2 3 4 5 6 Tanaka, K.L.; Senske, D.A.; Price, M.; Kirk, R.L. (1997). "Physiography, geomorphic/geologic mapping, and stratigraphy of Venus" (in Venus II, eds. Bougher, S.W. et al.). The University of Arizona Press. pp. 667–694. ISBN 0816518300.

[Banerdt_etal_Venus_II-5] Banerdt, W.B.; McGill, G.E.; Zuber, M.T. (1997). Plains Tectonics on Venus (in Venus II, eds. Bougher, S.W. et al.). The University of Arizona Press. pp. 901–930. ISBN 0816518300.

[Basilevsky_and_Head_1996-6] 1 2 Basilevsky, A.T.; Head, J.W. (June 1, 1996). "Evidence for rapid and widespread emplacement of volcanic plains on Venus: Stratigraphic studies in the Baltis Vallis region". Geophysical Research Letters. 23 (12): 1497–1500. Bibcode:1996GeoRL..23.1497B. doi:10.1029/96GL00975.

[Baker_etal_1992-7] 1 2 3 4 Baker, V.R.; Komatsu, G.; Parker, T.J.; Gulick, V.C.; Kargel, J.S.; Lewis, J.S. (Aug 25, 1992). "Channels and Valleys on Venus: Preliminary Analysis of Magellan Data". Journal of Geophysical Research. 97 (E8): 13, 421–13, 444. Bibcode:1992JGR....9713421B. doi:10.1029/92JE00927.

[Baker_etal_1997_Venus_II-8] 1 2 3 4 Baker, V.R.; Komatsu, G.; Gulick, V.C.; Parker, T.M. (1997). Channels and Valleys (in Venus II, eds. Bougher, S.W. et al.). The University of Arizona Press. pp. 757–793. ISBN 0816518300.

[Stofan_and_Smrekar_2005-9] 1 2 3 4 5 Stofan, E.R.; Smrekar, S.E. (2005). "Large topographic rises, coronae, large flow fields, and large volcanoes on Venus: Evidence for mantle plumes?". Geological Society of America Special Paper. 388: 841–861. doi:10.1130/2005.2388(47).

[Crumpler_etal_1997_Venus_II-10] 1 2 3 4 5 Crumpler, L.S.; Aubele, J.C.; Senske, D.A.; Keddie, S.T.; Magee, K.P.; Head, J.W. (1997). Volcanoes and centers of volcanism on Venus (in Venus II, eds. Bougher, S.W. et al.). The University of Arizona Press. pp. 697–756. ISBN 0816518300.

[Stofan_etal_1997_Venus_II-11] Stofan, E.R.; Hamilton, V.E.; Janes, D.M; Smrekar, S.E. (1997). Coronae on Venus: Morphology and origin (in Venus II, eds. Bougher, S.W. et al.). The University of Arizona Press. pp. 931–965. ISBN 0816518300.

[Hansen_etal,_Venus_II-12] 1 2 Hansen, V.L.; Willis, J.J.; Banerdt, W.B. (1997). "Tectonic overview and synthesis" (in Venus II, eds. Bougher, S.W.). The University of Arizona Press. pp. 797–844. ISBN 0816518300.

[McKinnon_etal_1997_Venus_II-13] McKinnon, W.B.; Zahnle, K.J.; Ivanov, B.A.; Melosh, H.J. (1997). Cratering on Venus: Models and observations (in Venus II, eds. Bougher, S.W. et al.). The University of Arizona Press. pp. 969–1014. ISBN 0816518300.

[Herrick_etal_1997_Venus_II-14] Herrick, R.R.; Sharpton, V.L.; Malin, M.C.; Lyons, S.N.; Feely, K. (1997). Morphology and morphometry of impact craters (in Venus II, eds. Bougher, S.W. et al.). The University of Arizona Press. pp. 1015–1046. ISBN 0816518300.

[Greenley_etal_1997_Venus_II-15] Greenley, R.; Bender, K.C.; Saunders, R.S.; Schubert, G.; Weitz, C.M. (1997). Aeolian processes and features on Venus (in Venus II, eds. Bougher, S.W. et al.). The University of Arizona Press. pp. 547–589. ISBN 0816518300.

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