Sierra Madera - Hypervelocity Impact Crater

Alternate Names
Local Language
Coordinates 30° 35' 44" N; 102° 54' 47" W
Notes
  1. Southern edge of the Val Verde basin in West Texas, ~40 km S of Fort Stockton.
Country United States of America
Region Texas
Date Confirmed 1968
Notes
  1. Shatter cones are discovered (Howard and Offield, 1968).
Buried? No
Notes
  1. Half the structure is covered by Quaternary alluvium, which reached a thickness of ~15 m in the ring depression (Wilshire et al., 1972).
Drilled? Yes
Notes
  1. 5 holes, to a maximum depth of 5.5 km penetrate Permian and Cretaceous deformed strata and into the underlying unreformed Carboniferous to Precambrian (Wilshire et al., 1972).
Target Type Sedimentary
Notes
  1. Permian and Lower Cretaceous carbonates, shales and sandstones (Wilshire et al., 1972).
Sub-Type Carbonate, Mudstone, Sandstone, Shale
Apparent Crater Diameter (km) 20 km
Age (Ma) <113
Notes :
  1. Minimum age: Poorly constrained by overlying quaternary alluvium deposits, up to ~15 m thick in the ring depression (Wilshire et al., 1972). Maximum age: 113 Ma determined by stratigraphic constraints: youngest deformed unit is the Georgetown Formation (Albian, Early Cretaceous) (Wilshire et al., 1972). The impact likely occurred after the Lower Cretaceous strata were deposited but before they were completely consolidated, thus in the Late Cretaceous or Early Tertiary (Howard et al., 1972).

Method :
  1. Stratigraphy
Impactor Type Unknown

Advanced Data Fields

Notes

Erosion
6
  1. Remnant crater-fill products are preserved and the crater's central uplift is exposed (Grieve, 1982).
Final Rim Diameter
Unknown
Apparent Rim Diameter
20 km
  1. On the basis of a new relationship to derive the apparent diameter using maximum shatter cone extent, the diameter is 20 km (Osinski and Ferriere, 2016). Previous apparent diameter was 13 km. (Wilshire et al., 1972)
Rim Reliability Index
1
  1. Composed of a central uplift, a surrounding structural depression 0.8 to 106 km wide and a raised rim (Wilshire et al., 1972).
Crater Morphology
Complex
Central Uplift Diameter
4.5km
Central Uplift Height
200 m
Uplift Reliability Index
3
Structural Uplift
1.2 km
Thickness of Seds
Target Age
Palaeozoic Mesozoic
Marine
No
Impactor Type
Other Shock Metamorphism
No
Shatter Cones
Yes
  1. The occurrence of abundant and extremely well-developed shatter cones is first reported at Sierra Madera in (Dietz, 1960). Shatter cones abound in the central uplift of the structure and they occur as far as 6.5 km from the centre (Howard and Offield, 1968). "Whole cones and clusters of whole cones having a common axial orientation are found in places, but segments or partial cones, which may intersect at high angles, are more common. Cone segments may have any orientation relative to bedding" (Wilshire et al., 1972). In aphanitic dolomite, cones are preferentially developed on joint and bedding surfaces. Shatter cones occur in dolomite, siltstone, fine-grained sandstone, and calcareous chert (least common in limestone). Whole cones range in height from less than 2 mm, up to 12 cm; incomplete cone segments can be as much as 45 cm long (Howard and Offield, 1968) (Wilshire et al., 1972). Shatter cones are more abundant toward the centre of the structure. Authors report on a "lithologic control of size of shatter cones", with cones typically of ~5 cm long in aphanitic dolomite, up to 12 cm in marly dolomite, and up to 20 cm long in sandy siltstone. Most of the cones are within 2 to 4 km from the centre of the structure (Howard and Offield, 1968) (Wilshire et al., 1972). Cones generally point in the same direction at the outcrop scale; however, at a few localities some segments point in a direction opposite to the dominant direction. Apical angles range from 75 to 108° and average 88.5° (Howard and Offield, 1968) (Wilshire et al., 1972). Macroscopic shatter cone samples with two complete cones pointing in opposite directions (within the Hess Formation) are presented by (Huson et al., 2011). Shatter cone samples in the Gilliam Limestone contain shocked quartz (up to 2 sets of PDFs are illustrated in (Huson et al., 2011)). Shatter cones also occur as fragments (of chert) within polymict breccias (Huson et al., 2011).
Planar Fractures
No
Planar Deformation Features
Yes
  1. PDF (omega, pi) in quartz grains (Wilshire et al., 1972).
Diaplectic Glass
No
Coesite
No
Stisovite
No
Crater Fill
LB, M
  1. (Wilshire et al., 1972) identified two types of impact generated breccias: (1) "monolithic breccia" which is monomict and is the most widespread, and (2) "mixed breccias" which are polymict. (Huson et al., 2007) reported rocks with immiscible silica/carbonate melts (clast-bearing melt rocks). Polymict breccias can also be observed as dykes.
Proximal Ejecta
Distal Ejecta
Dykes
LB
Volume of Melt
Depth of Melting

References

Spot a missing reference? Submit Reference

P D Jr Lowman (1965) Magnetic reconnaissance of Sierra Madera, Texas, and nearby igneous intrusions, New York Academy of Sciences, Annals 123, p. 1182-1197, url

A O Kelly (1966) A water impact hypothesis for the Sierra Madera structure in Texas, Meteoritics 3(2), p. 79-82, url

H G Wilshire, K A Howard (1968) Structure pattern in central uplifts of cryptoexplosion structures as typified by Sierra Madera, Science 162(3850), p. 258-261, url

H G Wilshire, Keith A Howard, T W Offield (1971) Impact breccias in carbonate rocks, Sierra Madera, Texas, Geological Society of America Bulletin 82(4), p. 1009-1017, Geological Society of America (GSA), Boulder, CO, url, doi:http://dx.doi.org/10.1130/0016-7606(1971)82[1009:IBICRS]2.0.CO;2

K A Howard, T W Offield, H G Wilshire (1972) Structure of Sierra Madera, Texas, as a guide to central peaks of lunar craters, Geological Society of America Bulletin 83(9), p. 2795-2808, Geological Society of America (GSA), Boulder, CO, url, doi:http://dx.doi.org/10.1130/0016-7606(1972)83[2795:SOSMTA]2.0.CO;2

H G Wilshire, T W Offield, K A Howard, D Cummings (1972) Geology of the Sierra Madera cryptoexplosion structure, Pecos County, Texas, p. 47, url

R A F Grieve, C A Wood, J B Garvin, G McLaughlin, J F McHone (1988) Impact craters in North America, Astronaut's Guide to Terrestrial Impact Craters, p. 10, url

S A Huson, M C Pope, A J Watkinson, F F Foit (2005) Possible planar elements in zircon as indicator of peak impact pressures from the Sierra Madera impact crater, West Texas, Lunar and Planetary Science Conference XXXVI, p. 1-2, pdf

S A Huson, F F Foit, A J Watkinson, M C Pope (2006) X-ray diffraction powder patterns and thin section observations from the Sierra Madera impact structure, Lunar and Planetary Science XXXVII, p. 2377, pdf

T J Goldin, K Wünnemann, H J Melosh, G S Collins (2006) Hydrocode modeling of the Sierra Madera impact structure, Meteoritics & Planetary Science 41(12), p. 1947-1958, url, doi:10.1111/j.1945-5100.2006.tb00462.x

S A Hudson, M C Pope, Franklin F Foit, A J Watkinson (2007) Immiscibility features between silica-rich and carbonate-rich material in breccia from the Sierra Madera impact structure, Lunar and Planetary Science Conference XXXVII, p. 5-6, pdf

T Adachi, G Kletetschka (2008) Impact-pressure controlled orientation of shatter magnetizations in Sierra Madera, Texas, USA, Studia Geophysica et Geodaetica 52, p. 237-254, url

S a Huson, Franklin F Foit, a J Watkinson, M C Pope (2009) Rietveld analysis of X-ray powder diffraction patterns as a potential tool for the identification of impact-deformed carbonate rocks, Meteoritics & Planetary Science 44(11), p. 1695-1706, doi:10.1111/j.1945-5100.2009.tb01200.x

S A Dulin, Richard Douglas Elmore, D P Dennie, S C Evans, P Mulvany (2011) Paleomagnetic investigations of the Decaturville, MO and Sierra Madera, TX impact structures, 42nd Lunar and Planetary Science Conference, p. 2-3, pdf, doi:10.1029/2007GL030113.

S Huson, M Pope, A J Watkinson, F F Foit (2011) Deformational features and impact-generated breccia from the Sierra Madera impact structure, West Texas, Bulletin of the Geological Society of America 123(1-2), p. 371-383, url, doi:10.1130/B30183.1

J R V Lopik, R A Geyer (2015) Gravity and magnetic anomalies of the Sierra Madera, Texas, "Dome", Science 142(3588), p. 45-47, url

K A Howard, T W Offield (2015) Shatter cones at Sierra Madera, Texas, Science 162(3850), p. 261-265, url

Enrico Flamini, A Coletta, M L Battagliere, M Virelli (2019) Sierra Madera, USA, Encyclopedic Atlas of Terrestrial Impact Craters, p. 609-611, Springer, Cham, url, doi:https://doi.org/10.1007/978-3-030-05451-9_169