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

TY - JOUR

T1 - Kilometre-scale sand injectites in the intracratonic Murzuq Basin (South-west Libya): an igneous trigger?

AU - Moreau, Julien

AU - Ghienne, Jean-Francois

AU - Hurst, Andrew

PY - 2012/6

Y1 - 2012/6

N2 - Mount Telout, situated at the edge of the Murzuq Basin, is a 325m high conical hill within a circular collapse structure that records 0·5km 3 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 10km 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.

AB - Mount Telout, situated at the edge of the Murzuq Basin, is a 325m high conical hill within a circular collapse structure that records 0·5km 3 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 10km 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.

KW - 1171 Geosciences

U2 - 10.1111/j.1365-3091.2011.01308.x

DO - 10.1111/j.1365-3091.2011.01308.x

M3 - Journal article

SN - 0037-0746

VL - 59

SP - 1321

EP - 1344

JO - Sedimentology

JF - Sedimentology

IS - 4

ER -