Geology of the Baluchistan (Pakistan) Portion of the Southern Margin of the Tethys Sea

McCormick, George R.

doi:10.1007/978-94-009-2253-2_15

Cited by 6 publications

(4 citation statements)

References 6 publications

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“…The history of the Bela volcanics is poorly understood, but they might have been emplaced when the carbonate platform passed over a hot spot in the mantle as the Indian plate moved northward. McCormick (1989) supported this idea, and referred to the rocks as within-plate alkali basalts associated with volcanic islands.…”

Section: Pre-ghazij Depositionmentioning

confidence: 89%

“…From 80 to 53 Ma (Late Cretaceous to early Eocene) the Indian subcontinent's progress accelerated to perhaps 20 cm/yr (Powell, 1979). Sometime during Late Cretaceous to Paleocene time, the leading edge of the marine shelf that was positioned off the Indian subcontinent approached the subduction zone, and sea-floor material in the form of submarine volcanic rocks and deep-water sediments were obducted onto carbonateplatform deposits (McCormick, 1989). Many workers (Powell, 1979;Besse and others, 1984;Patriat and Achache, 1984;Searle and others, 1987;Scotese and others, 1988;Ricou, 1994) have placed the initial collision between 55 and 50 Ma (early Eocene).…”

Section: Pre-ghazij Plate Tectonicsmentioning

confidence: 99%

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Lithofacies, depositional environments, and regional stratigraphy of the lower Eocene Ghazij Formation, Balochistan, Pakistan

Johnson¹,

Warwick²,

Roberts³

et al. 1999

Professional Paper

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Section: Pre-ghazij Depositionmentioning

confidence: 89%

Section: Pre-ghazij Plate Tectonicsmentioning

confidence: 99%

Lithofacies, depositional environments, and regional stratigraphy of the lower Eocene Ghazij Formation, Balochistan, Pakistan

Johnson¹,

Warwick²,

Roberts³

et al. 1999

Professional Paper

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“…This arc has been formed at the southern margin of the Afghan Block, in response to the northward subduction of the Neo‐Tethyan Ocean (Arthurton, Alam, Anisuddin‐Ahmad, & Iqbal, 1979; Arthurton, Farah, & Ahmed, 1982; Farah, Abbas, Dejong, & Lawrence, 1984; Sillitoe, 1978; Stoneley, 1974). It was described to be an accreted mass of oceanic islands by McCormick (1989) or an oceanic island arc by Siddiqui (1996) and Gnos et al (2000).…”

Section: Geological Background and Field Geologymentioning

confidence: 99%

Petrological and geochemical characterization of metamorphic sole rocks beneath the RasKoh ophiolite, western Pakistan: Implication for a Late Cretaceous supra‐subduction zone‐type forearc

et al. 2021

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Small, isolated outcrops of metamorphic sole rocks to the RasKoh ophiolite are exposed south‐east of the RasKoh Arc range, western Pakistan. These crop out as thin slices beneath the sheared serpentinites, and consist of amphibolites, epidote‐bearing amphibolites, and muscovite‐rich amphibolites with granoblastic, grano‐nematoblastic, and porphyroblastic textures. Geochemically, amphibolites present two compositional groups. Group‐I amphibolites are alkaline and enriched in light rare‐earth elements (LREE; LaN/YbN = 11.47–11.60) with Sr‐Nd isotopic compositions of (87Sr/86Sr)i = 0.705481–0.706128, (143Nd/144Nd)i = 0.512668–0.512672, and lower values of εNd(t) (+2.24 to +2.32). While, Group‐II amphibolites are tholeiitic with LREE‐depleted signatures (LaN/YbN = 0.88–1.31), (87Sr/86Sr)i = 0.706103–0.706303, (143Nd/144Nd)i = 0.512851–0.512936, and higher values of εNd(t) (+5.81 to +7.47). Primitive mantle‐normalized and other geochemical diagrams indicate that the protoliths for Group‐I amphibolites are oceanic island basalts (OIB). Conversely, Group‐II amphibolites are more akin to subduction‐related arc tholeiites with geochemical signatures, slightly enriched in large‐ion lithophile elements and with negative Nb‐Ta anomalies. The geothermobarometric results estimate that these rocks were metamorphosed at amphibolite facies at 690°C and 6.5 kbar. Alkaline volcanism is well documented from the other Mesozoic ophiolites of Neo‐Tethyan suture zones. We suggest that the OIB accreted to the base of the obducted plate at an early stage, whereas the island arc tholeiites (IAT) basalts metamorphosed and accreted to the base of the RasKoh ophiolite at a later stage. The OIB‐ and IAT‐type magmas as protolith of amphibolites suggest that the RasKoh ophiolite was emplaced in a supra‐subduction zone‐type forearc in Late Cretaceous (ca. 68–64 Ma).

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“…The Bibai and Bela volcanic rock suites are thought to be associated with hotspot activity and are recognized as alkali basalts [117][118][119][120][121]. They are dominated by amygdaloidal pillow basalts and basaltic volcaniclastic rocks.…”

Section: Sediment Provenancementioning

confidence: 99%

Lower Paleogene Tectonostratigraphy of Balochistan: Evidence for Time-Transgressive Late Paleocene-Early Eocene Uplift

Khan

Clyde

2013

Geosciences

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Analysis of lithofacies, paleoflow directions, and sandstone petrography of upper Paleocene-lower Eocene paralic and continental sediments exposed along the transpressional suture zone of the western margin of the Indian plate indicate that the process of deformation and uplift of the carbonate shelf in this area had started by late Paleocene time. This tectonic uplift and deformation is documented by: (1) an overall shallowing upward synorogenic sequence of sediments, (2) proximal conglomerate facies (consisting of lower Paleocene and Mesozoic clasts) dominating in the western part of the study area and distal facies of sandstone and shale dominating in the eastern part of the study area, (3) the existence of an unconformity of late Paleocene-early Eocene age in the Quetta and Kalat regions, (4) paleocurrent directions in deltaic and fluvial deposits indicating southeastward flowing sediment dispersal paths during late Paleocene-early Eocene time, which is opposite to that found in the late Cretaceous, suggesting a reversal in the depositional slope of the Cretaceous shelf, and (5) petrographic study of sandstones indicating a collision suture/fold thrust belt provenance. This episode of uplift and deformation could be the result of India-Arabian transpression with associated ophiolite obduction or, more likely, to represent the local response to initial India-Asia contact. The unroofing pattern and uplift geometry of the western Indian shelf suggests that this tectonism first started in the southern part of the study area (Kalat-Khuzdar area) during the late Paleocene-early Eocene and proceeded northward in a time-transgressive fashion

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Geology of the Baluchistan (Pakistan) Portion of the Southern Margin of the Tethys Sea

Cited by 6 publications

References 6 publications

Lithofacies, depositional environments, and regional stratigraphy of the lower Eocene Ghazij Formation, Balochistan, Pakistan

Lithofacies, depositional environments, and regional stratigraphy of the lower Eocene Ghazij Formation, Balochistan, Pakistan

Petrological and geochemical characterization of metamorphic sole rocks beneath the RasKoh ophiolite, western Pakistan: Implication for a Late Cretaceous supra‐subduction zone‐type forearc

Lower Paleogene Tectonostratigraphy of Balochistan: Evidence for Time-Transgressive Late Paleocene-Early Eocene Uplift

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