Tilted block faulting

Tilted block development adapted from 2013 Whitney et al., "Continental and oceanic core complexes". The cartoon illustrates how the fault blocks tilt as time progresses in an extensional environment. Time A shows the pre-deformed rock unit. At time B, incipient normal faulting begins. At time C, faulting continues as extension continues. The associated extensional basins begin to fill with eroded material from the exposed blocks.[1]
A time lapse view of the fault block progression.[1]

Tilted block faulting, also called rotational block faulting, is a mode of structural evolution in extensional tectonic events, a result of tectonic plates stretching apart.[1][2] When the upper lithospheric crust experiences extensional pressures, the brittle crust fractures, creating detachment faults.[3] These normal faults express themselves on a regional scale; upper crust fractures into tilted fault blocks, and ductile lower crust ascends.[1] This results in uplift, cooling, and exhumation of ductilely deformed deeper crust.[4] The large unit of tilted blocks and associated crust can form an integral part of metamorphic core complexes,[5] which are found on both continental and oceanic crust.[1][6]

  1. ^ a b c d e Whitney, D. L.; Teyssier, C.; Rey, P.; Buck, W. R. (21 December 2012). "Continental and oceanic core complexes". Geological Society of America Bulletin. 125 (3–4): 273–298. doi:10.1130/B30754.1.
  2. ^ Gibbs, A. D. (1 July 1984). "Structural evolution of extensional basin margins". Journal of the Geological Society. 141 (4): 609–620. Bibcode:1984JGSoc.141..609G. doi:10.1144/gsjgs.141.4.0609.
  3. ^ Brian Wernicke (25 June 1981). "Low-angle normal faults in the Basin and Range Province: nappe tectonics in an extending orogen". Nature. 291 (5817): 645–648. Bibcode:1981Natur.291..645W. doi:10.1038/291645A0. ISSN 1476-4687. S2CID 4269466. Wikidata Q29397670.
  4. ^ Coleman, Drew S.; Walker, J. Douglas (14 January 1994). "Modes of Tilting During Extensional Core Complex Development". Science. 263 (5144): 215–218. Bibcode:1994Sci...263..215C. doi:10.1126/science.263.5144.215. PMID 17839181.
  5. ^ Reynolds, Stephen (2002). Subsurface geology of the easternmost Phoenix basin, Arizona: Implications for groundwater flow. Arizona Geological Survey.
  6. ^ Lars Stemmerik, ed. (2004). The Jurassic of North-East Greenland. Copenhagen: GEUS. ISBN 978-87-7871-135-9.