Ramgarh - Hypervelocity Impact Crater

Alternate Names N/A
Coordinates 25° 19' 48" N; 76° 37' 12" E
Notes
  1. Located ~110 km NE of Kota and ~350 km SSW of Delhi.
Country India
Region Rajasthan
Date Confirmed 2020
Notes
  1. Confirmed based on the the presence of PDFs, PFs, and feather features in quartz grains (Kenkmann et al., 2020).
Buried? No
Notes
  1. Much of the structure is blanketed by Quaternary sand and soil deposits (Kenkmann et al., 2020).
Drilled? Yes
Notes
  1. A 452 m deep borehole was drilled into the centre of the structure in 1981-1982 (Kenkmann et al., 2020).
Target Type Sedimentary
Notes
  1. The Rewa and Bhander Groups (mainly sandstones) are exposed. The lack of a visible crater rim may indicate the rocks around the rim were semi- or unconsolidated at the time of impact and soft sediment deformation near the rim suggest a possible shallow marine imapct. Quaternary deposits of sand and soil cover most of the structure (Kenkmann et al., 2020).
Sub-Type Limestone, Sandstone, Shale, Siltstone
Apparent Crater Diameter (km) 10 km
Age (Ma) 165 - 750
Notes :
  1. 165-750 Ma, or possibly ~165 Ma, based on stratigraphic and biostratigraphic age constraints (Ray et al., 2003) (Kenkmann et al., 2019). Gastropods embedded within diamictite are Middle Jurassic (Callovian) in age and may indicate the time of the impact (Kenkmann et al., 2020). *Minimum age poorly constrained but based on Quaternary deposits covering most of structure (Kenkmann et al., 2020).

Method :
  1. Biostratigraphy
Impactor Type Unknown

Advanced Data Fields

Notes

Local Language
N/A
Erosion
4
  1. Central uplift is mostly exposed and preserved while the apparent crater rim is mostly eroded and only exposed along several river beds (Kenkmann et al., 2020).
Final Rim Diameter
Unknown
Apparent Rim Diameter
10 km
  1. Previous studies suggested the uplifted ring (3.5-4 km in diameter) was the rim of the crater but is now shown to be the outer part of the central uplift of a larger 10 km diameter impact structure based on large-scale concentric low-angle normal faults (Kenkmann et al., 2020).
Rim Reliability Index
2
  1. The annular ring feature making up the central uplift is 3.5 to 4 km in diameter and rises ~200 m above the surrounding flat terrain. Previous studies suggested this was the rim of the crater. Central uplift shows a stratigraphic uplift of ~1000 m and is rectangular in shape (Kenkmann et al., 2020).
Crater Morphology
Complex
Central Uplift Diameter
3.5 to 4 km
Central Uplift Height
200 m
Uplift Reliability Index
3
Structural Uplift
1 km
Thickness of Seds
Unknown
Target Age
PrecambrianMesozoicCenozoic
Marine
No
Impactor Type
Unknown
Other Shock Metamorphism
Feather features
  1. Feather features were identified in 6 quartz grains (Kenkmann et al., 2020).
Shatter Cones
No
  1. So far shatter cones have not been found (Kenkmann et al., 2020).
Planar Fractures
Yes
  1. 13 quartz grains contained PFs (Kenkmann et al., 2020).
Planar Deformation Features
Yes
  1. Four quartz grains with PDFs were identified (Kenkmann et al., 2020).
Diaplectic Glass
No
Coesite
No
Stisovite
No
Crater Fill
LB
  1. Polymict and monomict breccias were identified within the central uplift and as float (Kenkmann et al., 2020).
Proximal Ejecta
Unknown
Distal Ejecta
Unknown
Dykes
Unknown
Volume of Melt
Unknown
Depth of Melting
Unknown

References

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A. V. Murali, Kamlesh P. Lulla (1992) Ramgarh crater, rajasthan, india: Study of multispectral images obtained by indian remote sensing satellite (IRS‐IA), Geocarto International 7(3), doi:10.1080/10106049209354382

A Dutta, D Raychaudhuri, A Bhattacharya (2018) The Ramgarh structure, Rajasthan India: A meteorite impact crater?, 49th Lunar and Planetary Science Conference, p. 1293-1293, Houston: Lunar and Planetary Science Conference, pdf

S Misra, P K Srivastava, Md Arif (2019) Remote sensing, structural and rock magnetic analyses of the Ramgarh structure of SE Rajasthan, Central India—Further clues to its impact origin and time of genesis, Tectonics and Structural Geology: Indian Context, S Mukherjee (ed.), p. 327-352, Cham: Springer, Cham, url, doi:10.1007/978-3-319-99341-6_11

T Kenkmann, Gerwin Wulf, Amar Agarwal (2019) India's third impact crater: Ramgarh, Rajasthan, Large Meteorite Impacts and Planetary Evolution VI, p. 5007-5007, Brasília: Lunar and Planetary Institute, pdf

T Kenkmann, Gerwin Wulf, Amar Agarwal (2020) Ramgarh, Rajasthan, India: A 10 km diameter complex impact structure, Meteoritics & Planetary Science 55(4), p. 936-961, University of Arkansas, url, doi:10.1111/maps.13454

D Ray, S Misra, D Upadhyay, H E Newsom, E J Peterson, A Dube, M Satyanaryanan (2020) Iron-nickel metallic components bearing silicate-melts and coesite from Ramgarh impact structure, west-central India: Possible identification of the impactor, Journal of Earth System Science 129(1), p. 0118-0118, url, doi:10.1007/s12040-020-1371-7