A reassessment of the tectonic zonation of the Uralides: implications for metallogeny
Published:January 01, 2005
R. J. Herrington, V. N. Puchkov, A. S. Yakubchuk, 2005. "A reassessment of the tectonic zonation of the Uralides: implications for metallogeny", Mineral Deposits and Earth Evolution, I. McDonald, A. J. Boyce, I. B. Butler, R. J. Herrington, D. A. Polya
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A review of the structural zonation of the ‘oceanic’ Urals shows that only its westernmost Sakamara, Tagil and Magnitogorsk zones reveal the presence of thrust structures, whereas in the East Uralian megazone and Trans-Uralian zone, the classic zonation rather reflects late- or post-collisional granitic welding and strike-slip displacement of the orogen for 100–300 km. This sinistral strike-slip displacement is responsible for the lens-shapes structure of the individual zones in the Urals.
Metallogenically, these orogen-parallel faults and the eastern boundary of the East European craton control the distribution of the orogenic Au deposits. Restoration of the individual zones into their pre-strike-slip fault positions suggests that the Urals contains only two magmatic arcs, one in the west and one in the east. The western Tagil-Magnitogorsk immature arc hosts a variety of chromite, Alaska-type PGE and major VMS deposits. The eastern Valerianovka arc effectively stitches together the Kazakh-Tien Shan structures and is host to important copper-gold and giant iron(-copper) skarn deposits.
The geodynamic evolution of the Urals can be observed with the generation of the immature Tagil-Magnitogorsk magmatic arc in the Late Ordovician. Metallogenic zoning of the VMS deposits supports the petrological data that the arc developed due to eastward subduction inside the oceanic back-arc basin that existed in the rear of the Kazakhstan-Tien Shan arcs. In the late Palaeozoic, these arcs collided with each other and were together thrust onto the East European craton. Syncollisional granitoid intrusions welded the magmatic arcs, which were soon displaced into presently observed fragments along the post-collisional orogen-parallel strike-slip faults.
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Mineral Deposits and Earth Evolution
Mineral deposits are not only primary sources of wealth generation, but also act as windows through which to view the evolution and interrelationships of the Earth system.
Deposits formed throughout the last 3.8 billion years of the Earth’s history preserve key evidence with which to test fundamental questions about the evolution of the Earth. These include: the nature of early magmatic and tectonic processes, supercontinent reconstructions, the state of the atmosphere and hydrosphere with time, and the emergence and development of life. The interlinking processes that form mineral deposits have always sat at the heart of the Earth system and the potential for using deposits as tools to understand that evolving system over geological time is increasingly recognized. This volume contains research aimed both at understanding the origins of mineral deposits and at using mineral deposits as tools to explore different long-term Earth processes.