Ediacaran (similar to 620 Ma) high-grade regional metamorphism in the northern Arabian Nubian Shield: U-Th-Pb monazite ages of the Elat schist

摘要

Ediacaran times witnessed a hemisphere-scale orogenesis, forming the extensive Pan-African mountain ranges and resulting in the final assembly of the Gondwana supercontinent. The Elat metamorphic association (S Israel), located at the northernmost tip of the Arabian Nubian Shield (ANS), comprises amphibolite-facies pelitic and psammitic schists and orthogneisses and was presumably shaped by Ediacaran East African orogenesis. However, the timing, number and duration of metamorphic events in Elat and elsewhere in the ANS are inconclusive and a major emphasis was previously given to pre-Ediacaran island-arc related tectonics. Here U-Th-Pb dating of monazite, a precise chronometer of metamorphic mineral growth, is systematically applied to the Elat schist and unveils the tectono-metamorphic evolution of the Elat association.