Preprints
Filtering by Subject: Geochemistry
Tempo of magma degassing and the genesis of porphyry copper deposits
Published: 2017-10-25
Subjects: Earth Sciences, Geochemistry, Physical Sciences and Mathematics, Volcanology
Porphyry deposits are copper-rich orebodies formed by precipitation of metal sulphides from hydrothermal fluids released from magmatic intrusions that cooled at depth within the Earth’s crust. Finding new porphyry deposits is essential because they are our largest source of copper and they also contain other strategic metals including gold and molybdenum. However, the discovery of giant porphyry [...]
Lake Baikal isotope records of Holocene Central Asian precipitation
Published: 2017-10-23
Subjects: Earth Sciences, Geochemistry, Geology, Physical Sciences and Mathematics
Climate models currently provide conflicting predictions of future climate change across Central Asia. With concern over the potential for a change in water availability to impact communities and ecosystems across the region, an understanding of historical trends in precipitation is required to aid model development and assess the vulnerability of the region to future changes in the hydroclimate. [...]
Metrology and Traceability of U-Pb Isotope Dilution Geochronology (EARTHTIME Tracer Calibration Part I)
Published: 2017-10-23
Subjects: Earth Sciences, Geochemistry, Geology, Physical Sciences and Mathematics
Mixed 235U–233U–205Pb(–202Pb) tracers for U–Pb isotope-dilution isotope ratio mass spectrometry have been prepared under the auspices of the EARTHTIME Initiative. The methods and results for the preparation and calibration of the U/Pb ratio and isotopic abundances are given, and the various sources of uncertainty are discussed and quantified. The accuracy of the EARTHTIME U–Pb tracer isotopic [...]