10.6084/M9.FIGSHARE.9917759
Habib Mollai
Habib
Mollai
Rahim Dabiri
Rahim
Dabiri
Habib Allah Torshizian
Habib Allah
Torshizian
Georgia Pe-Piper
Georgia
Pe-Piper
Wei Wang
Wei
Wang
Cadomian crust of Eastern Iran: evidence from the Tapeh Tagh granitic gneisses
<p>Late Neoproterozoic to Early Cambrian (Cadomian) magmatic rocks are abundant in Iran, but their occurrence in east-central Iran is voluminous. This paper reports, for the first time, on the Cadomian rocks of the eastern Iranian region known as Tapeh Tagh and deals with their geochemistry and uranium-lead (U-Pb) zircon ages. The Tapeh Tagh region contains masses of Cadomian meta-igneous rocks (including various types of granitic gneiss) and overlying meta-sedimentary rocks. The granitic gneisses show tectonic contact with metasedimentary rocks and their connection appears to have been obscured during the younger tectonic movements. The granitic gneisses show mylonitic texture with quartz ribbons and feldspar augen. Laser Ablation Inductively Coupled Plasma Mass Spectrometry U-Pb dating of zircon grains, separated from medium to coarse-grained gneissic rocks, consistently yielded near concordant to discordant pairs of 527 ± 5 and 522 ± 10 Ma. Geochemically, these rocks show a felsic composition with SiO<sub>2</sub> content varying from 70.30 to 79.63 wt.%, a high content of FeO(t), alkalis, and incompatible trace elements (Zr, Nb), along with high ratios of Ga/Al and FeO(t)/MgO. They have fractionated rare earth element (REE) patterns with La/Yb = 9.1–24.7. Eu shows depletion with Eu/Eu*<1. The highly fractionated granites of the Tapeh Tagh are geochemically classified into the volcanic arc granites (VAG) and within plate granite.The granitic gneisses are geochemically and geochronologically similar to other Cadomian granites and gneisses in other parts of Iran as well as the Cadomian magmatic rocks from Turkey. These widely disseminated Cadomian basement rocks in Iran and Turkey are considered as fragments of Neoproterozoic to Early Cambrian continental arcs that formed the northern active margin of Gondwanaland.</p>
Physical Sciences not elsewhere classified
Genetics
Evolutionary Biology
Environmental Sciences not elsewhere classified
Chemical Sciences not elsewhere classified
Developmental Biology
Cancer
Taylor & Francis
2022
2022-05-05
2023-05-30
Online resource
0 Bytes
10.1080/00206814.2019.1670100
CC BY 4.0