Plate Tectonics, Ophiolites, and Societal Significance of Geology: A Celebration of the Career of Eldridge Moores

This volume honors Eldridge Moores, one of the most accomplished geologists of his generation. The volume starts with a summary of Moores’ achievements, along with personal dedications and memories from people who knew him. Leading off the volume’s 12 chapters of original scientific contributions is Moores’ last published paper that presents an example of the Historical Contingency concept, which suggested that earlier subduction history may result in supra-subduction zone geochemical signatures for some magmas formed in non-subduction environments. Other chapters highlight the societal significance of geology, the petrogenesis of ophiolites, subduction zone processes, orogenic belt evolution, and other topics, covering the globe and intersecting with Moores’ interests and influences.
New tectonic model and division of the Ubendian-Usagaran Belt, Tanzania: A review and in-situ dating of eclogites
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Published:September 09, 2021
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CiteCitation
Nelson Boniface*, Tatsuki Tsujimori, 2021. "New tectonic model and division of the Ubendian-Usagaran Belt, Tanzania: A review and in-situ dating of eclogites", Plate Tectonics, Ophiolites, and Societal Significance of Geology: A Celebration of the Career of Eldridge Moores, John Wakabayashi, Yildirim Dilek, John Wakabayashi
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ABSTRACT
Records of high-pressure/low-temperature (HP-LT) metamorphic interfaces are not common in Precambrian orogens. It should be noted that the association of HP-LT metamorphic interfaces and strongly deformed ocean plate stratigraphy that form accretionary prisms between trenches and magmatic arcs are recognized as hallmark signatures of modern plate tectonics. In East Africa (Tanzania), the Paleoproterozoic Ubendian-Usagaran Belt records a HP-LT metamorphic interface that we consider as a centerpiece in reviewing the description of tectonic units of the Ubendian-Usagaran Belt and defining a new tectonic model. Our new U-Pb zircon age and the interpretations from existing data reveal an age between 1920 and 1890 Ma from the kyanite bearing eclogites. This establishment adds to the information of already known HP-LT metamorphic events at 2000 Ma, 1890–1860 Ma, and 590–520 Ma from the Ubendian-Usagaran Belt. Arc–back-arc signatures from eclogites imply that their mafic protoliths were probably eroded from arc basalt above a subduction zone and were channeled into a subduction zone as mélanges and got metamorphosed. The Ubendian-Usagaran events also record rifting, arc and back-arc magmatism, collisional, and hydrothermal events that preceded or followed HP-LT tectonic events. Our new tectonic subdivision of the Ubendian Belt is described as: (1) the western Ubendian Corridor, mainly composed of two Proterozoic suture zones (subduction at 2000, 1920–1890, Ma and 590–500 Ma) in the Ufipa and Nyika Terranes; (2) the central Ubendian Corridor, predominated by metamorphosed mafic-ultramafic rocks in the Ubende, Mbozi, and Upangwa Terranes that include the 1890–1860 Ma eclogites with mid-ocean ridge basalt affinity in the Ubende Terrane; and (3) the eastern Ubendian Corridor (the Katuma and Lupa Terranes), characterized by reworked Archean crust.
- absolute age
- Africa
- dates
- East Africa
- eclogite
- high pressure
- in situ
- low temperature
- metamorphic rocks
- nesosilicates
- orthosilicates
- P-T conditions
- Paleoproterozoic
- plate collision
- plate tectonics
- Precambrian
- pressure
- Proterozoic
- rifting
- silicates
- Tanzania
- temperature
- U/Pb
- upper Precambrian
- zircon
- zircon group
- magmatic arcs
- Ubendian-Usagaran Belt