Session – Metamorphism at Extreme Conditions: The Important Role of UHP and UHT Rocks in Deciphering Lithosphere Evolution


Considered to represent “exotic” and generally unattainable PT-environments as recently as 30 years ago, ultrahigh-pressure (UHP) and ultrahigh-temperature (UHT) metamorphic rocks are now considered to be common and widespread. UHP-metamorphism describes equilibration at depths corresponding to PT-conditions attaining the coesite stability field, whereas UHT conditions refer to recrystallization temperatures > 900°C.

A dramatic increase in current research on UHP- and UHT-metamorphism reflects their significance in deciphering lithosphere evolution, and thus 30 years later we now have completely different views on processes such as mantle dynamics, crustal tectonics and fluid-rock interaction during subduction, collision and exhumation, crust-mantle interaction in subduction zones, geochemical recycling, etc. A completely new field of research has also developed as a result of new discoveries of UHP minerals and assemblages in ophiolitic bodies in Tibet (Luobusa) and the Polar Urals (Ray-Iz). Recent studies document that not only UHP but also UHT terranes (for instance in Inner Mongolia) can reach a lateral extent of hundreds of kilometers, which can be the result of common large-scale regional phenomena. It is intriguing to note that in SE Spain and in the Rif Belt in NW Africa, UHP mineral inclusions of microdiamond and coesite have just recently been discovered in garnet and kyanite of UHT granulites.

Many of these new findings triggered further experimental studies and modeling, and intensified future research should allow a better understanding of processes such as the subduction of oceanic and continental lithosphere, recycling of surface carbon and fluids to mantle depths, and later ascent towards the Earth’s surface.

 

Session convenor

Dr Hans-Peter Schertl (Germany)

Ruhr University Bochum

About the session convenor

Dr. Hans-Peter Schertl,
Senior research scientist
Institute of Geology, Mineralogy and Geophysics,
Ruhr-University Bochum, 44780 Bochum, Germany,

Diploma, Ruhr-University Bochum, Germany, 1987
Ph.-D., Ruhr-University Bochum, Germany, 1992

Research Interests:
Petrology, geochemistry, and geochronology of high-pressure and ultrahigh-pressure metamorphic rocks. Cathodoluminescence microscopy.
63 scientific papers published, 6 books/chapters in books; H-index 21.

Professional activities / awards:
2000-2004: Member – International Lithosphere Program: Projekt III-8 „Processes and Geodynamics in the Formation and Exhumation of Ultrahigh-Pressure metamorphic Terrains“. 2005-2009: Member – International Lithosphere Program: Projekt II-10, “Ultra-Deep Continental Crust Subduction“. Since 2001: National Representative (Germany): International Eclogite Conference Co-ordinating Comittee (I.E.C.C.C.). 2007-2011: Member – IGCP 546: Subduction zones in the Caribbean. 2011-2014: Member – The Leibniz Graduate School “Raw Materials, Innovation and Technology of Ancient Cultures” (RITaK). January 2014: Professeur invité, Département de Géosciences, Ecole Normale Supérieure, Paris, France. 2012-2013: Distinguished lecturer „Mineralogical Society of America“. Since 2014: Secretary “International Mineralogical Association” (IMA). 2014: Fellow Mineralogical Society of America“. 2015-2017: President “International Eclogite Conference Co-ordinating Committee” (IECCC). 2015-2020: Member – IGCP 649: Diamonds and Recycled Mantle. Since 2016: Editorial board: Journal of Earth Science. Since 2017: Adjunct Professor – College of Earth Science and Engineering, Shandong University of Science and Technology. 2017-2019: Member: Distinguished Public Service Medal Committee, Mineralogical Society of America (MSA).