Crustal evolution of the early earth: The role of major impacts

Frey, Herbert

doi:10.1016/0301-9268(80)90012-1

Cited by 51 publications

(19 citation statements)

References 21 publications

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“…The unusual circular features referred to as coronae or ovoids could be the result of endogenic reworking of large impact basins, in accord with some ideas about the origin of some very old terrestrial structures [Salisbury and Ronca, 1966;Ronca, 1966;Goodwin, 1974;Frey, 1980;Grieve, 1980;Florensky et aL, 1981]. It is in the Early Precambrian of the Earth that corona-like features have been discovered, although as a rule they are much smaller [Saul, 1978;Gintoy, 1978;Eggers, 1979;Salop, 1982;Ilyin et aL, 1983; and others].…”

Section: The Area Between Sedna Planitia and Bell Regiosupporting

confidence: 55%

The geology and geomorphology of the Venus surface as revealed by the radar images obtained by Veneras 15 and 16

Barsukov¹,

Basilevsky²,

Burba³

et al. 1986

J. Geophys. Res.

317

181

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A region‐by‐region condensed description of almost all of the area that was radar‐photographed by Veneras 15 and 16 is presented. Using some generalizations, the diversity of terrain was reduced to a discrete set from which a geological‐morphological map was constructed. The predominant type of terrain of the studied area is a plain that was tentatively subdivided into five morphological types: ridge‐and‐band, patchy rolling plain, dome‐and‐butte plain, smooth plain, and high smooth plain. Stratigraphically, the ridge‐and‐band plains are the oldest and the smooth plains are the youngest. The stratigraphic position of the other types is yet to be determined. Large sections of the plains show similarities to the mare‐type basaltic plains of the moon, Mercury, and Mars. Other types of terrain are combinations of ridges and grooves in various patterns: linear parallel, orthogonal, diagonal or chevron‐like, and chaotic. In some places the ridge‐and‐groove terrain is Stratigraphically below the plain material, but in other places it appears to be plain material that has been subsequently deformed. Near the eastern and western boundaries of Ishtar Terra large (several hundred kilometers in diameter) ring‐like features can be seen that are named coronae or ovoids. Evidence of tectonic deformation and the presence of flow‐like patterns support their designation as volcano‐tectonic features. Beta Regio seems to be an uplifted plain showing evidence of rifting and volcanism. All types of terrain are sparesely peppered with craters of obvious impact morphology. Their average density gives the plain an age range of 0.5 to 1×109 years. The fact that many impact craters are still in the pristine state indicates a very low rate of surface reworking, at least for the last 0.5 to 1×109 years. No evidence for water‐erosion‐sedimentation processes has been found. The tectonic activity of Venus has no equivalent on the moon, Mercury, or even Mars, and can be compared only with that of the Earth. Intensive horizontal deformation, previously known only on Earth, occurs on Venus, but in a characteristic Venusian style.

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Section: The Area Between Sedna Planitia and Bell Regiosupporting

confidence: 55%

The geology and geomorphology of the Venus surface as revealed by the radar images obtained by Veneras 15 and 16

Barsukov¹,

Basilevsky²,

Burba³

et al. 1986

J. Geophys. Res.

317

181

View full text Add to dashboard Cite

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“…Consideration of the effects of impact events on the largescale geologic evolution of the earth has been limited to models dealing with the period of high impact flux prior to -4.0 by ago and the potential influence of hundreds to thousands of kilometer-sized impact basins on the establishment of the basic dichotomy between continental and oceanic crust (Frey, 1980;Grieve, 1980). The recent discoveries, however, of enrichments in siderophile elements at numerous Cretaceous-Tertiary boundary sites have led to hypotheses linking a major impact event or series of events to biological extinctions (Alvarez and others, 1980;Ganapathy, 1980;Hsu, 1980;Kyte and others, 1980;Smith and Hertogen, 1980).…”

Section: Introductionmentioning

confidence: 99%

The record of impact on Earth: Implications for a major Cretaceous/Tertiary impact event

Grieve¹

1982

Geological Society of America Special Papers

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Approximately one hundred terrestrial hypervelocity impact structures, ranging in diameter from a few tens of meters to ~ 140 km, are currently known. All are on land, with major concentrations occurring on the North American and European cratons. With the exception of three, all recognized structures are Phanerozoic in age, with ~35% being <100 my old. There is no known structure commensurate in age with an impact event of the magnitude proposed in the hypothesis of Alvarez and others (1980) for an impact-induced biological crisis at the Cretaceous-Tertiary boundary. A size-frequency distribution of N<*D" 2 for large terrestrial impact structures and a calculated cratering rate of 0.35 x 10' 14 km" 2 y" 1 for structures with D >20 km, indicates, however, that an impact event capable of producing a < 200 km-sized structure may be expected somewhere on the earth's land surface every 65 m.y. There are three or four known structures with D >25 km and ages of 65 ± 5 m.y. This, however, may not represent a statistically significant increase in the cratering rate at the end of the Cretaceous.Consideration of cratering mechanics indicates that if the proposed Cretaceous-Tertiary impact event occurred in the ocean it had the potential to locally excavate the oceanic crust and bring upper mantle material to the surface, thus producing an as yet to be detected geophysical anomaly. Although cratering efficiency calculations suggest that ~10 3 projectile masses of material may be excavated in a major impact event, the bulk of this ejecta is locally confined. If, as has been suggested, the siderophile-enrichments in the Cretaceous-Tertiary boundary layer indicate the presence of projectile-contaminated ejecta from a major impact, then the source of this material is most likely early-time ejecta accelerated upwards as the projectile is penetrating the target rocks. This is supported by the relative abundance and distribution of meteoritic siderophile elements in impact melt rocks, which indicate that the bulk (~95%) of the projectile mass may be lost from the immediate area of the crater. The difficulties in defining projectile types from siderophile anomalies in the relatively well-known environment of impact melt rocks suggest that more detailed geochemistry and mineralogy will be necessary before the siderophile enrichments at the Cretaceous-Tertiary boundary can be linked to a specific meteoritic compositional class. In general, the record of terrestrial cratering is not inconsistent with the proposal that a major impact event occurred at the Cretaceous-Tertiary boundary. It does not, however, supply any direct confirmation that such an event produced a biological crisis.•Contribution from the Earth Physics Branch No. 967. 25on April 5, 2015 specialpapers.gsapubs.org Downloaded from

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“…Extraterrestrial flux = mass of incoming material / surface area of Earth = 60,000,000 kg / 510,100,000 km 2 = ~ 0.1 kg/km 2 /year (4) This value (~0.1 kg/km 2 /year) for the modern Earth impactor flux [Equation (4)] is modelled to have been 1,000 times greater during the Late Heavy Bombardment (LHB), ~3.9-3.8 Ga [42][43][44] , therefore roughly 100 kg/km 2 /year. This flux represents the absolute maximum for extraterrestrial input to Earth at any point during its history, perhaps equalled solely in the initial stages of planetary accretion [45] .…”

Section: Exogenous Organic Moleculesmentioning

confidence: 99%

Stochastic Prebiotic Chemistry within Realistic Geological Systems

et al. 2016

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This review introduces its readers to a ‘stochastic approach’ to origins of life research, from the viewpoints of both prebiotic chemistry and geology. The idea of a “primordial soup” has been subject to extensive criticism from thermodynamic, biochemical and geochemical perspectives, yet recent advancements have made clearer the plausibility of this theory. Herein, we review the theoretical and experimental approaches which have previously been explored, among these modelling, laboratory‐confined and geologically motivated experimentation. Of these, we consider organo‐mineral interactions, uniting aspects of prebiotic chemistry and geology, to be an especially promising way forward. However, we aim here to advance current approaches by advocating a methodology involving chemical systems and their stochastic reactivity on heterogeneous geological surfaces. This models the origins of life as a continuity of chemical reactions in an analogue to the early Earth (Hadean) environment.

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Crustal evolution of the early earth: The role of major impacts

Cited by 51 publications

References 21 publications

The geology and geomorphology of the Venus surface as revealed by the radar images obtained by Veneras 15 and 16

The geology and geomorphology of the Venus surface as revealed by the radar images obtained by Veneras 15 and 16

The record of impact on Earth: Implications for a major Cretaceous/Tertiary impact event

Stochastic Prebiotic Chemistry within Realistic Geological Systems

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