Geochemistry and apatite U-Pb geochronology of alkaline gabbros from the Nodoushan plutonic complex, Sanandaj-Sirjan Zone, Central Iran: Evidence for Early Palaeozoic rifting of northern Gondwana

Alavijeh, Badieh Shahsavari
Rashidnejad-Omran, Nematollah
Toksoy Köksal, Fatma
Chew, David
Szopa, Krzysztof
Ghalamghash, Jalil
Gaweda, Aleksandra
The Zagros Orogen formed during the Cenozoic collision of Arabia with Eurasia and resulted in the closure of the Neo-Tethys Ocean. Collision was preceded by a complicated tectonic history involving Pan-African orogenesis, Late Palaeozoic rifting and the formation of Neo-Tethys, and subsequent Mesozoic convergence on the northern margin of the ocean contemporaneous with ophiolite obduction on its southern margin. The Sanandaj-Sirjan Zone (SaSZ) is a metamorphic belt within the Zagros Orogen of Gondwanan provenance. U-Pb zircon geochronology has revealed the presence of Pan-African igneous and metamorphic basement complexes, in addition to minor late Palaeozoic plutons and abundant Jurassic plutonic rocks. This study presents a LA-ICP-MS U-Pb apatite age of 440.7 +/- 3.7 Ma from a gabbroic body on the central north-eastern margin of the SaSZ (Nodoushan region). Based on petrography and geochemistry, en route fractional crystallization of ascending magma was an important process in the evolution of the intrusive rocks. Geochemical characteristics imply that the south-west Nodoushan alkaline gabbroic magma was originated from the asthenospheric mantle source, whereas the high ratios of (La/Yb)(N) and (Dy/Yb)(N) are related to the low degree of partial melting from the garnet-bearing mantle source. Enrichment pattern of Nb, Ta, and Ti and depletion of Rb, Th, and Y are similar to the OIB pattern and intraplate alkaline magmatic rocks. High epsilon(Nd)(t) values (+1.29 to +1.50), low initial Sr isotopic ratios (0.703679-0.704098), and trace element ratios (e.g., Nb/La, Ce/Pb, Ba/Nb, and Th/Nb) indicate that crustal contamination was insignificant in its petrogenesis. The petrogenesis of the Nodoushan alkaline gabbroic rocks could be related to the presence of extensional phase, upwelling and decompressional melting of asthenospheric mantle in the rift basin which was associated with the opening of the Paleo-Tethys Ocean in Late Ordovician to Silurian times.


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The volcanic province of North-West Turkey contains a number of intra-continental alkaline volcanic eruption sequences formed along the localized extensional basins developed in relation with the Late Cenozoic extensional processes. The volcanic suite comprises the extracted melt products of adiabatic decompression melting of the mantle that are represented by small-volume intra-continental plate volcanic rocks of alkaline olivine basalts and basanites with compositions representative of mantle-derived, pri...
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Six box-cores, one boomerang core and one hundred sixty-six surface sediment samples recovered in the Sea of Marmara were analyzed in an attempt to establish the main controls on distribution and origin of trace metals within the oxic to suboxic basin of this sea.
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Black Sea consists of two separate back arc basins which opened at different times during the Cretaceous in response to northward subduction of the Neo-Tethys Ocean. The paucity of well data, complex geometries and seismic imaging challenges mean that questions remain regarding the basement architecture though most authors accept that, at least in part, both these basins are floored by oceanic crust, even though there are no magnetic stripes. Interpretation of deep, long offset seismic data (imaging to more...
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Multiproxy sedimentological analyses along 4.9 m-long sequence of Boraboy Lake, which is located on the central eastern part of the North Anatolian Fault (NAF), reveal the sedimentary traces of past large earthquakes in the region. The lake has a relatively large catchment area (10 km(2)) compared to its size (0.12 km(2)), which renders sedimentation sensitive to heavy rain/storm events. Accordingly, the background sedimentation, which is composed of faintly laminated reddish/yellowish brown clayey silt, is...
Sub-ophiolite metamorphic rocks from NW Anatolia, Turkey
Onen, AP; Hall, R (Wiley, 2000-09-01)
The metamorphic rocks from near Kutahya in north-west Anatolia record different stages in the history of closure of the Neo-Tethyan Izmir-Ankara-Erzincan ocean. Sub-ophiolite metamorphic rocks within the Tavsanli zone are a tectonically composite sequence of quartz-mica schists, amphibole schists, amphibolites and garnet amphibolites. They show increasing metamorphic grade towards the base of the ophiolite. A first metamorphic event, typical of sub-ophiolite metamorphic sole rocks, was characterized by high...
Citation Formats
B. S. Alavijeh et al., “Geochemistry and apatite U-Pb geochronology of alkaline gabbros from the Nodoushan plutonic complex, Sanandaj-Sirjan Zone, Central Iran: Evidence for Early Palaeozoic rifting of northern Gondwana,” GEOLOGICAL JOURNAL, pp. 1902–1926, 2019, Accessed: 00, 2020. [Online]. Available: