Kilometer-scale sand injectites in the intracratonic Murzuq Basin (South-west Libya): an igneous trigger?

Julien Moreau, Jean Francois Ghienne, Andrew Hurst

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17 Citations (Scopus)

Abstract

Mount Telout, situated at the edge of the Murzuq Basin, is a 325 m high conical hill within a circular collapse structure that records 0Æ5 km3 of sand intrusion into Silurian shales. Based on a comparison with other similar circular collapse structures around the Murzuq Basin, it is argued that sand injection in the form of pipes occurred during the Devonian. The overpressures triggering the process are inferred to result from a combination of: (i) tectonic uplift at a basin scale that initially focused regional ground water flows; and (ii) igneous intrusion within the sand-rich Cambrian–Ordovician strata. The palaeorelief buried under the regionally extensive Silurian shales may have locally focused overpressures and localized sand injection at the 1 to 10 km scale. The Mount Telout injected sandbody and related features offer exceptional, seismic-scale outcrop analogues for sand injections that are
often identified in seismic reflection data. Large-scale sand injections might be essential in petroleum exploration of the North African Lower Palaeozoic basins as they form seal-bypass systems.
Original languageEnglish
Pages (from-to)1321-1344
Number of pages24
JournalSedimentology
Volume59
Issue number4
Early online date19 Dec 2011
DOIs
Publication statusPublished - Jun 2012

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Keywords

  • sand injectites
  • intracratonic
  • Murzuq Basin
  • kilometer-scale
  • circular structures
  • igneous intrusion
  • intracratonic basin
  • maars
  • North Africa
  • sand injection
  • tectonic uplift
  • vents

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