Tenoumer - Hypervelocity Impact Crater
| Alternate Names | |
| Local Language | |
| Coordinates |
22° 55' 4" N; 10° 24' 23" W Notes
|
| Country | Mauritania |
| Region | Tiris Zemmour |
| Date Confirmed | 1970 Notes
|
| Buried? |
No Notes
|
| Drilled? | No |
| Target Type |
Crystalline
Notes
|
| Sub-Type | Gneiss, Sedimentary, Granite |
| Apparent Crater Diameter (km) | Unknown |
| Age (Ma) | 1.57 ± 0.14 Notes :
Method :
|
| Impactor Type | Unknown |
Advanced Data Fields
Notes
- The ejecta blanket has been removed, although the rim has been partially preserved (Fudali and Cassidy, 1972).
- Rim-to-rim diameter is 6,300 ft (1.9 km) (Fudali and Cassidy, 1972).
- Consists of a filled-in crater depression surrounded by a rim, maximum relief of 110 m (French et al., 1970). Depths based on geophysics (Fudali and Cassidy, 1972). See also (Grieve et al., 1989).
- Lechatelierite inclusions in the melt rock (French et al., 1970) is extremely common, as well as ballen quartz (Jaret et al., 2009) (Schultze et al., 2016).
- PDF in quartz grains of inclusions in melt (French et al., 1969) (French et al., 1970). PDF in quartz with orientations matching "Type D" following the classification system by (Robertson et al., 1968) were observed in quartzofeldspathic inclusions within a lava sample (French et al., 1970). PDFs observed in distal melt ejecta, however, crystalline rocks of the crater floor and the most proximal ballistic ejecta show no evidence of shock deformation within either quartz or feldspar (Jaret et al., 2009) (Jaret et al., 2014). Quartz PDFs (Fig. 5) are found only as individual grains and in selected clasts within the impact-melt rock, and have orientations {1012}, {1013}, and {1011} (Jaret et al., 2014). Feldspar PDFs (Fig. 6) observed in both granitic clasts and in discrete individual grains within impact-melt rock, measure 1-3 µm wide with <5-10 µm separation between sets (Jaret et al., 2014). Deformation of feldspar occurs both with and without associated shocked quartz (Jaret et al., 2014). Up to 5 sets of PDFs were found in quartz grains but most common was 2-3 sets (Jaret et al., 2009). (Pratesi et al., 2005) report that many of the impact melt rock clasts are granite or gneiss showing distinctive impact features such as shocked quartz. Quartz grains inside lithic clasts, and feldspar grains in granite and gneiss clasts show PDFs (Schultze et al., 2016).
- Diaplectic quartz within the melt (Schultze et al., 2016).
- Clast-bearing melt rocks as small dyke-like bodies in "three isolated areas in a peripheral depression outside the present crater rim". They are less 20 m long and a few meters wide and "have apparently been emplaced in discontinuous fractures oriented roughly concentric to the crater". Glass forms the matrix of the melt (French et al., 1970). Lechatelierite in melt. This specimen consists of a heterogeneous glassy to cryptocrystalline groundmass commonly containing shocked country rock fragments and lechatelierit (Fudali, 1974). "Based on the field relations, the Tenoumer impact meltbreccias could represent a form of emplacement by injection into a conical or semiconical fracture system" (Fudali, 1974). Vesicular melt-matrix breccias (M) that occurs as patches in proximal ejecta. They are described as clast-rich impact melt rocks. Glassy and nonglassy varieties can be observed (Jaret et al., 2014). Melt rocks occur as patches of a few tens of meters outside the crater and range between crystalline and glassy. Silicate-carbonate liquid immiscibility (Pratesi et al., 2015).
References
(1948) Le cratere d'explosion de Tenoumer et l'existence probable d'une grande fracture rectiligne au Sahara occidental, Comptes Rendus Hebdomadaires des Seances de l'Academie des Sciences 227(3), p. 213-214, Gauthier-Villars, Paris
(1951) Note et correspondance a propos des crateres meteoriques, Rev. Geog. Lyon (Etudes Rhodan.) 26(3), p. 357-359, url
(1966) Le cratere de Tenoumer (Mauritanie) et ses laves, Bulletin de la Societe Geologique de France 8(2), p. 165-172, Societe Geologique de France, Paris, url
(1967) Decouverte de laves basaltiques dans le cratere du Temimichat (Ghallaman, Mauritanie), Comptes Rendus Hebdomadaires des Seances de l'Academie des Sciences, Serie D: Sciences Naturelles 265(17), p. 1164-1166, Gauthier-Villars, Paris
(1969) Shock-metamorphic features at the Tenoumer crater, Mauritania, Eos, Transactions, American Geophysical Union 50(4), p. 221, American Geophysical Union, Washington, DC
(1970) Tenoumer crater, Mauritania; age and petrologic evidence for origin by meteorite impact, Journal of Geophysical Research 75(23), p. 4396-4406, American Geophysical Union, Washington, DC, url
(1974) Genesis of the Melt Rocks at Tenoumer Crater, Mauritania, Journal of Geophysical Research 79(14), p. 2115-2121, American Geophysical Union, Washington, DC, url, doi:http://dx.doi.org/10.1029/JB079i014p02115
(1975) Does impact produce chemical fractionation?, Eos, Transactions, American Geophysical Union 56(6), p. 389-390, American Geophysical Union, Washington, DC
(1980) Bowl-shaped impact craters and circular depressions in Algeria, International Geological Congress, Abstracts--Congres Geologique Internationale, Resumes 3(26), p. 1250, [International Geological Congress], [location varies]
(1991) Gradational evolution of young, simple impact craters on the Earth, Abstracts of Papers Submitted to the Lunar and Planetary Science Conference 22, Graham Ryder, Virgil L Sharpton (ed.), p. 483-484, Lunar and Planetary Science Conference, Houston, TX, url
(1994) Early fluvial degradation in Terra Tyrrhena, Mars; constraints from styles of crater degradation on the Earth, Abstracts of Papers Submitted to the Lunar and Planetary Science Conference 25, Part 1, p. 457-458, Lunar and Planetary Science Conference, Houston, TX, url
(2003) The age of Tenoumer Crater, Mauritania, revisited, Abstracts of Papers Submitted to the Lunar and Planetary Science Conference 34, p. abstr. no. 1183, Lunar and Planetary Science Conference, Houston, TX, url
(2003) Gravity transect profile and PDF/PF comparisons from the Bee Bluff structure, Abstracts of Papers Submitted to the Lunar and Planetary Science Conference 34, p. abstr. no. 2076, Lunar and Planetary Science Conference, Houston, TX, url
(2005) Chemical compositions of impact melt breecias and target rocks from the Tenoumer impact crater, Mauritania, Meteoritics & Planetary Science 40(11), p. 1653-1672, url, doi:10.1111/j.1945-5100.2005.tb00137.x
(2006) Geomorphology and late Cenozoic paleogeography of Lake Elgygytgyn (central Chukchi), Geomorfologiya 2006(1), p. 57-69, Nauka, Moscow
(2009) Petrographic investigation of ejecta from the Tenoumer impact crater, Abstracts of Papers Submitted to the Lunar and Planetary Science Conference 40, p. 1281, Lunar and Planetary Science Conference, Houston, TX, pdf
(2009) Feldspar deformation as an indicator of low-barometry shock; petrographic investigation of ejecta from the Tenoumer impact crater, Mauritania, Abstracts with Programs - Geological Society of America 41(7), p. 313, Geological Society of America (GSA), Boulder, CO
(2014) Progressive deformation of feldspar recording low-barometry impact processes, Tenoumer impact structure, Mauritania, Meteoritics & Planetary Science 49(6), p. 1007-1022, Meteoritical Society, Fayetteville, AR, url, doi:http://dx.doi.org/10.1111/maps.12310
(2016) Tenoumer impact crater, Mauritania: Impact melt genesis from a lithologically diverse target, Meteoritics & Planetary Science 51(2), p. 323-350, University of Arkansas, doi:10.1111/maps.12593