Petrography, geochemistry, and provenance of the Chalki rocks in Kurdistan region, North Iraq

Ali, Sarmad A; Omer, Muhamed F.; Aqrawi, Ahmed M.

doi:10.1007/s12517-016-2545-0

Cited by 1 publication

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“…Some Ordovician successions in northern Iraq are associated with intrusive tholeiitic Chalky volcanic rocks. The Chalky volcanic rocks fall in the compositional field of non-arc-related-rocks, well within the field of the mid-ocean ridge basalt-ocean island basalt mantle array (Ali, Omer, & Aqrawi, 2016). The single euhedral zircon grain from the Khabour Formation, which is dated to this period (490 Ma), may derive from nearby magmatic rocks from Ordovician northern Gondwana uplift.…”

Section: Neoproterozoic Zircon Decreases To Approximately 19% Inmentioning

confidence: 66%

Provenance of northern Gondwana Lower Ordovician sandstones (Khabour Formation, northern Iraq) revealed by detrital zircon using LA‐ICP‐MS dating

et al. 2021

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We present new zircon U/Pb provenance data using laser ablation induced coupled plasma mass spectroscopy (LA-ICP-MS) for eight samples of mature quartz arenites and subarkosic sandstones of the Lower Ordovician Khabour Formation, northern Iraq, to establish their depositional age and provenance. The samples were collected from thin-to medium-bedded sandstones along profiles of the Chalky Nasara and Ora sections. Most analysed detrital zircon analyses are concordant within 100 ± 10% and include a prevalence of Proterozoic over Archean ages. Collectively, the data can be divided into four main age groups: (a) Neoproterozoic ages, 570-1,000 Ma (58%); (b) Mesoproterozoic ages, 1,000-1,500 Ma (10%); (c) Palaeoproterozoic ages, 1,620-2,480 Ma (21%); and (d) Archean ages, 2,500-3,300 Ma (11%). The predominance of Cryogenian-Ediacaran ages (850-550 Ma) reflects major magmatic events associated with the assembly of northern Gondwana. The major age group at $600 Ma likely represents the unroofing of late-stage granitic rocks from the Arabian-Nubian Shield. The lack of zircons younger than 490 Ma suggests that Lower Ordovician sandstones in northern Iraq were probably deposited on the distal shelf of the northern Gondwana passive margin and were not influenced by rifting and magmatism in northern Gondwana caused by the opening of Palaeo-Tethys. Diagenetic xenotime overgrowths are common on detrital zircon grains, but radiometric dating of these was not possible.

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Section: Neoproterozoic Zircon Decreases To Approximately 19% Inmentioning

confidence: 66%