Thomas Pettke

University of Bern, Institute of Geological Sciences, Faculty Member

Subduction Zones +17

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Papers

Antigorite dehydration fluids boost carbonate mobilisation and crustal CO2 outgassing in collisional orogens

Geochimica et Cosmochimica Acta

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Trace element and oxygen isotope study of eclogites and associated rocks from the Münchberg Massif (Germany) with implications on the protolith origin and fluid-rock interactions

Chemical Geology, 2021

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Magma genesis and Cu-Au ore formation (Apuseni Mountains, Romania) in light of Pb, Sr and Nd isotopic and chemical trends

Geochemistry of eolian dust from sediment core LL44-GPC-3, supplement to: Pettke, Thomas; Halliday, Alex N; Rea, David K (2002): Cenozoic evolution of Asian climate and sources of Pacific seawater Pb and Nd derived from eolian dust of sediment core LL44-GPC3. Paleoceanography, 17(3), 1031

The large-diameter piston core LL44-GPC3 from the central North Pacific Ocean records continuous ... more The large-diameter piston core LL44-GPC3 from the central North Pacific Ocean records continuous sedimentation of eolian dust since the Late Cretaceous. Two intervals resolved by Nd and Pb isotopic data relate to dust coming from America (prior to ~40 Ma) and dust coming from Asia (since ~40 Ma). The Intertropical Convergence Zone (ITCZ) separates these depositional regimes today and may have been at a paleolatitude of ~23°N prior to 40 Ma. Such a northerly location of the ITCZ is consistent with sluggish atmospheric circulation and warm climate for the Northern Hemisphere of the early to middle Eocene. Since ~40 Ma, correlations between Nd (~7.55 > epsilon-Nd(t) > ~10.81) and Pb (18.625 < 206/4Pb < 18.879; 15.624 < 207/4Pb < 15.666; 38.611 < 208/4Pb < 38.960; 0.8294 < 207/6Pb < 0.8389; 2.0539 < 208/6Pb < 2.0743) isotopes reflect the progressive drying of central Asia triggered by the westward retreat of the paleo-Tethys. Comparisons between the c...

The relation between 2 Li ↔ Na substitution and hydrogen bonding in five-periodic 3 single-chain silicates nambulite and marsturite: A single crystal X-ray study

Revision 1 1 Magnetic anisotropy in natural amphibole crystals 2 3

15 Anisotropy of magnetic susceptibility (AMS) is often used as a proxy for mineral fabric in 16 ... more 15 Anisotropy of magnetic susceptibility (AMS) is often used as a proxy for mineral fabric in 16 deformed rocks. In order to do so quantitatively, it is necessary to quantify the intrinsic 17 magnetic anisotropy of single crystals of rock-forming minerals. Amphiboles are common in 18 mafic igneous and metamorphic rocks and often define rock texture due to their general 19 prismatic crystal habits. Amphiboles may dominate the magnetic anisotropy in intermediate to 20 felsic igneous rocks and in some metamorphic rock types, because they have a high Fe 21 concentration and they can develop a strong crystallographic preferred orientation. In this 22 study, the AMS is characterized in 28 single crystals and one crystal aggregate of 23 compositionally diverse clinoand ortho-amphiboles. High-field methods were used to isolate 24 the paramagnetic component of the anisotropy, which is unaffected by ferromagnetic 25 inclusions that often occur in amphibole crystals. Laue imaging, laser ablati...

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Fluid-rock Interactions recorded in Serpentinites subducted to 60-80 km Depth

Selected Conclusions 2 Combining the results with halogen [2] and noble gas data [3] suggests tha... more Selected Conclusions 2 Combining the results with halogen [2] and noble gas data [3] suggests that serpentinisation of oceanic lithospheric mantle occurred along bend faults or as detached slices in the shallow forearc by fluids equilibrated within the accretionary prism 2 Initial heterogeneities will govern the spatial extent of serpentinisation and FME enrichment, ultimately amplifying heterogeneities 2 FME enrichments from serpentinisation are largely retained and reincorporated into the convecting mantle, providing potential fractionation mechanisms for U-Th systematics (HIMU) and enriched mantle (EM) sources 2 FMEs such as As, Sb, W and Bi, which are rarely quantified, can provide essential information to further discriminate between serpentinisation environments

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Die "Welt" unter den Vulkanen

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Major to ultra trace element bulk rock analysis of nanoparticulate pressed powder pellets by LA-ICP-MS

An efficient, clean procedure for bulk rock major to trace element analysis by 193 nm Excimer LA-... more An efficient, clean procedure for bulk rock major to trace element analysis by 193 nm Excimer LA-ICP-MS analysis of nanoparticulate pressed powder pellets (PPPs) employing a binder is presented. Sample powders are milled in water suspension in a planetary ball mill, reducing average grain size by about one order of magnitude compared to common dry milling protocols. Microcrystalline cellulose (MCC) is employed as a binder, improving the mechanical strength of the PPP and the ablation behaviour, because MCC absorbs 193 nm laser light well. Use of MCC binder allows for producing cohesive pellets of materials that cannot be pelletized in their pure forms, such as quartz powder. Rigorous blank quantification was performed on synthetic quartz treated like rock samples, demonstrating that procedural blanks are irrelevant except for a few elements at the 10 ng g−1 concentration level. The LA-ICP-MS PPP analytical procedure was optimised and evaluated using six different SRM powders (JP-1, ...

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189 Chapter 12: Analytical Protocols for Element Concentration and Isotope Ratio Measurements in Fluid Inclusions by La–(Mc–)Icp–MS

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$Research paper thumbnail of Molybdenum isotope fractionation at upper-crustal magmatic-hydrothermal conditions$

Molybdenum isotope fractionation at upper-crustal magmatic-hydrothermal conditions

Chemical Geology, 2021

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The influence of oceanic oxidation on serpentinite dehydration during subduction

Earth and Planetary Science Letters, 2018

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From ocean to mantle: new evidence for U-cycling with implications for the HIMU source and the secular Pb isotope evolution of Earth's mantle

Lithos, 2018

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Evaluation of Major to Ultra Trace Element Bulk Rock Chemical Analysis of Nanoparticulate Pressed Powder Pellets by LA-ICP-MS

Geostandards and Geoanalytical Research, 2016

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Rb sbnd Sr isotopic analysis of fluid inclusions in quartz: Evaluation of bulk extraction procedures and geochronometer systematics using synthetic fluid inclusions

Geochimica Et Cosmochimica Acta, Oct 1, 1995

Radiogenic Hf isotopic composition of continental eolian dust in Pacific Ocean sediments, supplement to: Pettke, Thomas; Lee, Der-Chuen; Halliday, Alex N; Rea, David K (2002): Radiogenic Hf isotopic compositions of continental eolian dust from Asia, its variability and its implications for seawat...

Supplement to: Pettke, T et al. (2002): Radiogenic Hf isotopic compositions of continental eolian dust from Asia, its variability and its implications for seawater Hf. Earth and Planetary Science Letters, 202(2), 253-464, https://doi.org/10.1016/S0012-821X(02)00778-1, May 13, 2002

The inorganic silicate fraction extracted from bulk pelagic sediments from the North Pacific Ocea... more The inorganic silicate fraction extracted from bulk pelagic sediments from the North Pacific Ocean is eolian dust. It monitors the composition of continental crust exposed to erosion in Asia. 176Lu/177Hf ratios of modern dust are subchondritic between 0.011 and 0.016 but slightly elevated with respect to immature sediments. Modern dust samples display a large range in Hf isotopic composition (IC), -4.70 < epsilon-Hf < +16.45, which encompasses that observed for the time series of DSDP cores 885/886 and piston core LL44-GPC3 extending back to the late Cretaceous. Hafnium and neodymium isotopic results are consistent with a dominantly binary mixture of dust contributed from island arc volcanic material and dust from central Asia. The Hf-Nd isotopic correlation for all modern dust samples, epsilon-Hf= =0.78 epsilon-Nd = +5.66 (n =22, R**2 =0.79), is flatter than those reported so far for terrestrial reservoirs. Moreover, the variability in epsilon-Hf of Asian dust exceeds that predicted on the basis of corresponding epsilon-Nd values (34.76 epsilon-Hf < +2.5; -10.96< epsilon-Nd