Tectonic history and structural development of the Zallah-Dur al Abd Sub-basin, western Sirt Basin, Libya

Abdunaser, Khalifa; McCaffrey, Ken

doi:10.1016/j.jsg.2015.02.006

Cited by 17 publications

(9 citation statements)

References 11 publications

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“…The basement highs seem to reflect some form of subcrustal arching rather than magmatic intraplate accumulation as inferred from isotope geochemical data that indicate that the magmas lack signals of crustal contamination and, hence, most likely magma propagated directly from deep‐seated magma reservoirs at the crust‐mantle boundary (Elshaafi & Gudmundsson, ; Stuart et al, ). There are no large igneous bodies such as extensive sills observed in seismic lines in the western part of the Sirt Basin (e.g., Abdunaser & McCaffrey, ). Hence, the lack of large plutonic bodies or extinct shallow magma chambers beneath the Earth's crust may be one reason for the low Bouguer anomaly in volcanic areas as observed in this study.…”

Section: Discussionmentioning

confidence: 99%

Crustal Thickness Beneath Libya and the Origin of Partial Melt Beneath AS Sawda Volcanic Province From Receiver Function Constraints

et al. 2017

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This study investigates crustal thickness and properties within the Libyan region. Results obtained from 15 seismic stations belonging to the Libyan Center for Remote Sensing and Space Science are reported, in addition to 3 seismic stations publically available, using receiver functions. The results show crustal thicknesses ranging from 24 km to 36 km (with uncertainties ranging between ±0.10 km and ±0.90 km). More specifically, crustal thickness ranges from 32 km to 36 km in the southern portion of the Libyan territory then becomes thinner, between 24 km and 30 km, in the coastal areas of Libya and thinnest, between 24 km and 28 km, in the Sirt Basin. The observed high Vp/Vs value of 1.91 at one station located at the AS Sawda Volcanic Province in central Libya indicates the presence of either partial melt or an abnormally warm area. This finding suggests that magma reservoirs beneath the Libyan territory may still be partially molten and active, thereby posing significant earthquake and volcanic risks. The hypothesis of an active magma source is further demonstrated though the presence of asthenospheric upwelling and extension of the Sirt Basin. This study provides a new calculation of unconsolidated sediment layers by using the arrival time of the P to S converted phases. The results show sediments thicknesses of 0.4 km to 3.7 km, with the Vp/Vs values ranging from 2.2 to 4.8. The variations in crustal thickness throughout the region are correlated with surface elevation and Bouguer gravity anomalies, which suggest that they are isostatically compensated.

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Section: Discussionmentioning

confidence: 99%

Crustal Thickness Beneath Libya and the Origin of Partial Melt Beneath AS Sawda Volcanic Province From Receiver Function Constraints

et al. 2017

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“…As a result, the first‐order architecture and infilling history of the offshore Sirte Basin is poorly constrained, notably prior to the Upper Cretaceous (Figures and ). Several studies suggest that the Sirte Basin formed at the location of a former basement high, that is, the Paleozoic Arch, which separates the Cyrenaica platform from the Ghadames Basin (Figure ) farther west (Abdunaser & McCaffrey, ; Frizon de Lamotte et al, ; Massa & Delort, ; Wennekers et al, ). Most studies propose that the Sirte Basin underwent several phases of extension.…”

Section: Tectonostratigraphic Evolution Of the Ionian Basin Marginsmentioning

confidence: 99%

“…Most studies propose that the Sirte Basin underwent several phases of extension. However, in detail, a variable subsidence history seems to be recorded in the different subbasins (Abadi et al, 2008;Abdunaser & McCaffrey, 2015). A Middle to Upper Triassic extensional event is suggested, but its lateral extension and impact on the crustal architecture are poorly constrained (Del Ben & Finetti, 1991;Massa & Delort, 1984;Thusu, 1996;Wennekers et al, 1996).…”

Section: Sirte Segmentmentioning

confidence: 99%

Geology of the Ionian Basin and Margins: A Key to the East Mediterranean Geodynamics

et al. 2019

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We revisit the nature, structure, and evolution of the Ionian Basin and its surrounding passive margins (Apulia, Eastern Sicily/Malta, and Cyrenaica margins). Relying on geological observations (wells, dredges, and dives) and seismic calibrations from the surrounding platforms and escarpments, we present age correlations for the deepest sedimentary sequences of the Ionian Basin. Two‐ship deep refraction seismic data combined with reprocessed reflection seismic data enable us to identify, characterize, and map these thick sedimentary sequences and to present a consistent seismic stratigraphy across the basin. At a larger scale, we present new geological transects illustrating the tectonostratigraphic relationships between the Ionian Basin and its surrounding rifted margins. On this basis, we suggest that a Late Triassic‐Early Jurassic rifting preceded the late Early Jurassic to Middle Jurassic formation of the Ionian Basin. The combination of geophysical and geological arguments suggests that the entire deep basin is floored with oceanic crust of normal thickness, but with high seismic velocity in the upper part. Upscaling our results in the framework of the eastern Mediterranean, we propose that the Ionian Basin represents the remnant of a short‐lived oceanic basin resulting from the interaction between two propagating oceans: the Central Atlantic and the Neo‐Tethys.

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“…Different forms Figure 1 for location). Black patches = volcanic fields <30 Ma; colored circles = loci of volcanic samples described and analyzed in this study; labeled boxes = names of individual volcanic fields with ranges of radiometric dates taken from Ade-Hall et al (1975a), Bardintzeff et al (2012), Busrewil and Esson (1991), Cvetković et al (2010), Deniel et al (2015), Jurák (1978), Masoud (2014), Radivojević et al (2015), and Schult and Soffel (1973); dotted line = outline of Sirt Basin taken from Abdunaser and McCaffrey (2015). of sample screening are used to mitigate the effects of crystal fractionation, of lithospheric contamination, and of source heterogeneity.…”

Section: Introductionmentioning

confidence: 99%

“…It has probably been active for the last ∼25 Ma and consists of five major provinces that have a combined areal extent of ∼75,000 km 2 (Figure 2). The bulk of Libyan volcanism is aligned approximately northwest-southeast and is situated within or adjacent to the Sirt Basin, which was generated by Early Cretaceous rifting followed by thermal subsidence and Paleogene fault reactivation (Abadi et al, 2008;Abdunaser & McCaffrey, 2015). This basin consists of numerous northwest-southeast trending horst and graben structures that are draped by Eocene to Miocene postrift Long wavelength (i.e., >800 km) free-air gravity map calculated from DIR-R5 database (Bruinsma et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Quantifying Asthenospheric and Lithospheric Controls on Mafic Magmatism Across North Africa

Ball

White

Masoud

et al. 2019

Geochem Geophys Geosyst

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African basin‐and‐swell morphology is often attributed to the planform of subplate mantle convection. Across North Africa, the coincidence of Neogene and Quaternary (i.e., <23 Ma) magmatism, topographic swells, long wavelength gravity anomalies, and slow shear wave velocity anomalies within the asthenosphere provides observational constraints for this hypothesis. Admittance analysis of topographic and gravity fields corroborates the existence of subplate support. To investigate quantitative relationships between intraplate magmatism, shear wave velocity, and asthenospheric temperature, we collected and analyzed a suite of 224 lava samples from Tibesti, Jabal Eghei, Haruj, Sawda/Hasawinah, and Gharyan volcanic centers of Libya and Chad. Forward and inverse modeling of major, trace, and rare Earth elements was used for thermobarometric studies and to determine melt fraction as a function of depth. At each center, mafic magmatism is modeled by assuming adiabatic decompression of dry peridotite with asthenospheric potential temperatures of 1300‐1360 °C. Surprisingly, the highest temperatures are associated with the low‐lying Haruj volcanic center rather than with the more prominent Tibesti swell. Our results are consistent with earthquake tomographic models which show that the slowest shear wave anomalies within the upper mantle occur directly beneath the Haruj center. This inference is corroborated by converting observed velocities into potential temperatures, which are in good agreement with those determined by geochemical inverse modeling. Our results suggest that North African volcanic swells are primarily generated by thermal anomalies located beneath thinned lithosphere.

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Tectonic history and structural development of the Zallah-Dur al Abd Sub-basin, western Sirt Basin, Libya

Cited by 17 publications

References 11 publications

Crustal Thickness Beneath Libya and the Origin of Partial Melt Beneath AS Sawda Volcanic Province From Receiver Function Constraints

Crustal Thickness Beneath Libya and the Origin of Partial Melt Beneath AS Sawda Volcanic Province From Receiver Function Constraints

Geology of the Ionian Basin and Margins: A Key to the East Mediterranean Geodynamics

Quantifying Asthenospheric and Lithospheric Controls on Mafic Magmatism Across North Africa

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