Tectonics and Metallogeny of the Tethyan Orogenic Belt
The Tethyan orogenic belt stretches from the Alps, through the Carpathians and Balkans, Taurides and Caucasus, Zagros, Makran, and Himalayas, to Indochina and into the southwest Pacific Ocean. It represents a complete Wilson Cycle, from opening and closure of the Paleotethys Ocean in the mid-Paleozoic to the Late Triassic, opening of the Neotethys Ocean in the Permian-Early Triassic, and its progressive closure throughout the late Mesozoic and Cenozoic eras. The current state of the orogen includes all stages of convergence from active subduction beneath the Makran and eastern Mediterranean, through advanced continental collision in the Caucasus/Taurides and Zagros, to syn- to postcollisional readjustment in the Carpathians, Balkans, Himalayas, and Indochina (Richards, 2015).
The region has been the focus of significant recent attention from geologists interested both in its tectonic evolution and metallogeny, made possible by increased accessibility to many of the geographic sections of the orogen. Key breakthroughs in understanding its tectonic history have come through improved geochronological techniques and expansion of the database of samples and events dated, combined with more accurate paleogeographic and tectonic models. In parallel, an improved understanding of the subtle relationships between tectonomagmatic and metallogenic processes have refined interpretations that were once based on simplistic assumptions (e.g., that porphyry deposits only form above active subduction zones). Indeed, economic geologists have been among the key drivers of these advances by demanding more accurate and predictive tectonomagmatic models for ore formation that can reliably inform mineral exploration.
Consequently, the Tethyan orogen is now understood to be the best preserved global example of a collisional orogen, where all stages of convergence can be observed in real or recent geological time, and the detailed relationships to ore formation, commonly reflecting tectonic changes measured on submillion-year timescales, can be accurately documented and modeled.
In this volume, we present a selection of papers that showcase this advancement in knowledge, with examples from Eastern Europe to South Asia.Beginning in the Balkans, Knaak et al. (2016) describe the variety of mineral deposits that occur in the emergent worldclass Timok region of eastern Serbia. The origin of the Late Cretaceous Timok Magmatic Complex remains debated, but the authors propose that arc magmatism was focused by dextral transtensional structures, followed by complex structural rearrangement in the Cenozoic. Porphyry Cu-Au deposits, polymetallic replacement deposits, and sedimentary rockhosted Au deposits occur in close spatial, and possibly genetic, relationship to the Late Cretaceous arc rocks. A key contribution of this study is the detailed reconstruction of later Cenozoic fault movements that led to structural dislocation and oroclinal bending, complicating geologic and metallogenic correlations in the region.
Zircon Compositions as a Pathfinder for Porphyry Cu ± Mo ± Au Deposits
Published:January 01, 2016
Yong-Jun Lu, Robert R. Loucks, Marco Fiorentini, T. Campbell McCuaig, Noreen J. Evans, Zhi-Ming Yang, Zeng-Qian Hou, Christopher L. Kirkland, Luis A. Parra-Avila, Alan Kobussen, 2016. "Zircon Compositions as a Pathfinder for Porphyry Cu ± Mo ± Au Deposits", Tectonics and Metallogeny of the Tethyan Orogenic Belt, Jeremy P. Richards
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Zircon composition has great potential as a pathfinder for porphyry Cu ± Mo ± Au systems. The present study used a large integrated laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) U-Pb age and trace element dataset for both infertile and fertile magmatic suites in order to elucidate distinctive zircon signatures diagnostic of metallogenic fertility of the parent magma. The infertile suites are defined as magmatic rocks that are absent of alteration and mineralization at any grade, whereas fertile suites refer to the causative intrusions leading to porphyry-type ore formation. The infertile suites are relatively reduced S- and A-type and relatively...
- chemical ratios
- copper ores
- geochemical methods
- gold ores
- ICP mass spectra
- mass spectra
- metal ores
- mineral exploration
- molybdenum ores
- ore minerals
- porphyry copper
- rare earths
- trace elements
- zircon group