0000000000591806
AUTHOR
Thomas Theye
Neoproterozoic Rosetta Gabbro from northernmost Arabian–Nubian Shield, south Jordan : Geochemistry and petrogenesis
An Ediacaran mafic intrusion of south Jordan is a distinctive appinitic igneous rock with a possibly unique texture, characterized by spherical clots up to 40 mm in diameter composed of amphibole cores from which plagioclase euhedra radiate; we call it the Rosetta Gabbro. It is exposed as a small (ca. 750 m(2)) outcrop in the Neoproterozoic basement of south Jordan. A second outcrop of otherwise similar gabbro is located about 400 m to the north of the Rosetta Gabbro, but it lacks the distinctive texture. The Rosetta Gabbro could represent a magma pipe. It intrudes the Aqaba Complex (similar to 600 Ma) granitoids and metasediments of the Janub Metamorphic Complex (633-617 Ma). The gabbro is…
Geochemistry and P–T–t evolution of the Abu-Barqa Metamorphic Suite, SW Jordan, and implications for the tectonics of the northern Arabian–Nubian Shield
Abstract The Abu Barqa Metamorphic Suite (ABMS) represents the oldest part of the Arabian–Nubian Shield in southern Jordan. It comprises tonalitic gneiss, metasediments including schist and paragneiss, and granitic gneiss, intruded by later granitic bodies. Geochemically, the majority of the schist samples have shale and Fe-shale protoliths, while the paragneisses represent metagreywacke. Tectonic discrimination diagrams indicate that the protolith of the ABMS was deposited at an active continental margin/island arc setting. U–Pb zircon (SIMS) ages from metamorphic and igneous rocks of the ABMS indicate that it evolved between ∼800 and ∼610 Ma. A tonalitic gneiss has a crystallization age o…