Amguid - Hypervelocity Impact Crater

Alternate Names N/A
Coordinates 26° 5' 15" N; 4° 23' 42" E
Notes
  1. 90 km WSW of the old fort of Amguid and 225 km SE from the Oasis at In Salah in central Algeria.
Country Algeria
Region Tamanrasset
Date Confirmed 1980
Notes
  1. First proposed by (Lefranc, 1969). Confirmed by rare occurrences of PDF\'s in quartz grains and breccia veins in the crater wall (Lambert et al., 1980).
Buried? No
Notes
  1. Compacted aeolian silts surrounded by a ring of coarser gravels, washed from the crater walls, partially fill the depression (Lambert et al., 1980).
Drilled? No
Target Type Sedimentary
Notes
  1. Lower Devonian sandstones (Lambert et al., 1980) (Sahoui and Belhai, 2016).
Sub-Type Sandstone
Apparent Crater Diameter (km) 450 m
Age (Ma) 0.01 - 0.1
Notes :
  1. 10-100 ka (0.01-0.1 Ma) based on comparison with 25 ka Barringer crater (similar size, preservation, and desert environment), though Amguid might be slightly more eroded (Lambert et al. 1980) Maximum age: Devonian target rocks (Lambert et al. 1980)

Method :
  1. Morphology
Impactor Type Unknown

Advanced Data Fields

Notes

Local Language
N/A
Erosion
2
  1. Some ejecta, the rim and the breccia lens are preserved (Lambert et al., 1980).
Final Rim Diameter
Unknown
Apparent Rim Diameter
450 m
  1. A partial cross-section is included in (Lambert et al., 1980). Rim height (Lefranc, 1969), and a depth of 30 m (Sahoui and Belhai, 2016) (Sighinolf et al., 2020).
Rim Reliability Index
2
  1. Consists of a circular cavity with steep walls of upturned and overturned beds, a raised rim and a partially preserved ejecta blanket (Lambert et al., 1980). Uplifted sandstones at upper parts of the crater walls (Sahoui and Belhai, 2016).
Crater Morphology
Simple
Central Uplift Diameter
Unknown
Central Uplift Height
Unknown
Uplift Reliability Index
Unknown
Structural Uplift
Unknown
Thickness of Seds
Unknown
Target Age
Palaeozoic
Marine
No
Impactor Type
Unknown
Other Shock Metamorphism
Unknown
Shatter Cones
No
  1. No shatter cones occur according to (Lambert et al., 1980). The presence of \"pseudo-shatter cones\" (in sandstone) is reported by (Belhai et al., 2006).
Planar Fractures
No
Planar Deformation Features
Yes
  1. PDF in quartz grains was rare according to (Lambert et al., 1980), however, PDF in quartz was later documented in (Sahoui and Belhai, 2016).
Diaplectic Glass
No
Coesite
No
Stisovite
No
Crater Fill
LB
  1. A continous ejecta blanket extends up to 100 m from the rim. The target rocks (sandstones) \"do not show intense fracturing, shatter cones, or breccia veins\" (Lambert et al., 1980). The ejecta is described as sandstone debris.
Proximal Ejecta
LB
Distal Ejecta
Unknown
Dykes
Unknown
Volume of Melt
Unknown
Depth of Melting
Unknown

References

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J Lagrula, Clavedeo B, J N Delattre, J M Schuster, J J Walch (1973) Study on gravimetric anomalies of Algerian Sahara headland of Amguid and Taffassasset, Comptes Rendus Hebdomadaires des Seances de l'Academie des Sciences Serie D 276(8), p. 1261-1265

P Lambert, J F Jr McHone, R S Dietz, M Houfani (1980) Impact and impact-like structures in Algeria; Part I, Four bowl-shaped depressions, Meteoritics 15(2), p. 157-179, Tempe, AZ, United States (USA): Arizona State University, Center for Meteorite Studies, Tempe, AZ

C Koeberl (1994) African meteorite impact craters: characteristics and geological importance, Journal of African Earth Sciences 18(4), p. 263-295, doi:10.1016/0899-5362(94)90068-X

R Sahoui, D Belhai (2016) Impact metamorphism of sandstones at Amguid Crater, Algeria, 79th Annual Meeting of the Meteoritical Society

G P Sighinolfi, M Barbieri, D Brunelli, R Serra (2020) Mineralogical and chemical investigations of the Amguid crater (Algeria): is there evidence on an impact origin?, Geosciences 10(3), url, doi:10.3390/geosciences10030107