Emplacement of sandstone intrusions during contractional tectonics

Giuseppe Palladino, Antonio Grippa, Denis Bureau, G. Ian Alsop, Andrew Hurst

Research output: Contribution to journalArticle

14 Citations (Scopus)
9 Downloads (Pure)

Abstract

Sandstone injections are created by the forceful emplacement of remobilized sand in response to increases in overpressure. However, the contribution provided by horizontal compressive stress to the build-up in overpressure, and the resulting emplacement of sand injection complexes, is still to be substantiated by robust field observations. An opportunity to address this issue occurs in Central California where a large volume of sandstone intrusions record regionally-persistent supra-lithostatic pore-pressure. Detailed fieldwork allows sandstone-filled thrusts to be recognized and, for the first time, permits us to demonstrate that some sandstone intrusions are linked to contractional deformation affecting the western border of the Great Valley Basin. Fluidized sand was extensively injected along thrust surfaces, and also fills local dilatant cavities linked to thrusting. The main aims of this paper are to provide detailed descriptions of the newly recognized syn-tectonic injections, and describe detailed cross-cutting relationships with earlier sandstone injection complexes in the study area. Finally, an evolutionary model consisting of three phases of sand injection is provided. In this model, sand injection is linked to contractional tectonic episodes affecting the western side of the Great Valley Basin during the Early-Middle Cenozoic. This study demonstrates that sand injections, driven by fluid overpressure, may inject along thrusts and folds and thereby overcome stresses associated with regional contractional deformation. It is shown that different generations of sand injection can develop in the same area under the control of different stress regimes, linked to the evolving mountain chain.
Original languageEnglish
Pages (from-to)230-249
Number of pages19
JournalJournal of Structural Geology
Volume89
Early online date1 Jul 2016
DOIs
Publication statusPublished - Aug 2016

Keywords

  • Sand injections
  • Contractional tectonics
  • Bed-parallel slip
  • Great valley sequence
  • San Joaquin valley

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