Details

Autor(en) / Beteiligte

• Hassan, Mahmoud M.
• Dessouky, Osama K.
• Al Shammari, Abdullah M.
• Al Barakati, Adeeb N.
• Memish, Abdullah N.

Titel

Petrogenesis and geochemistry of the successive granitic events in the eastern Arabian Shield: implications for tectonic evolution and crustal thickening

Ist Teil von

• International journal of earth sciences : Geologische Rundschau, 2023-11, Vol.112 (8), p.2145-2160

Ort / Verlag

Berlin/Heidelberg: Springer Berlin Heidelberg

Erscheinungsjahr

2023

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• There is ongoing debate around the origin of successive granitic magmatic events in transitional stages from compressional to extensional tectonic settings in orogens. In the eastern part of the Arabian Shield, the late Cryogenian–Ediacaran magmatism of the transitional stage contributed to the growth of the Ad-Dawadmi terrane. The late Neoproterozoic Abt schist Formation, which is found throughout the Ad-Dawadmi terrane, is intruded by batholiths of the Najirah granitoids (~ 641 Ma) followed by the Khurs granite of the Ar Ruwaydah Suite (~ 612 Ma). A switch in geodynamic regime from post-collision to intra-plate extension was attended by the Hadbet Tayma alkali granites. This study utilizes petrology and whole-rock geochemistry to decipher the genesis of these three granitic intrusive events. The Najirah granitoids are metaluminous, late-orogenic, I-type granitoids generated from magma derived by partial melting of lower crustal mafic rocks. The younger Khurs granite of the Ar Ruwaydah suite reflects a post-orogenic setting and has predominantly peraluminous nature with S-type granite characteristics, supporting an origin by partial melting of the metagraywacke crust. A final anorogenic magmatic event produced a suite of A-type (A2-subtype) alkaline granites of Hadbet Tayma, which formed after the termination of the accretion and microplate amalgamation phase of the northern East African Orogeny (EAO). These three successive magmatic events provide evidence for a range of magmatic sources in the thickened crust of the eastern Arabian Shield, reflecting its tectonic evolution over time. Graphical Abstract