The late growth history of the terrestrial planets, from the last giant collisions with planetary embryos to the subsequent late bombardment with smaller objects, is of critical importance for understanding the early chemical differentiation processes and the evolution of the terrestrial planets. The goal of this research program is to improve our current understanding of the late-accretion history of the Earth, its Moon, and other terrestrial planets from 4.5 to 3.8 billion years ago. A multidisciplinary approach will provide novel insights into the timing and rates, chemical budget, and geodynamic implications of late accretion and will constrain the physicochemical boundary conditions during this time interval.
AB Geochemistry Projects in TRR 170 (Funding period 2016-2019):
- TRR 170-A1: Chronometric investigations of ancient lunar impact rocks. D. Vanderliek, H. Becker; T. Haber, E. Scherer.
- TRR 170-A3: Ancient bombardment of the inner solar system – Reinvestigation of the “fingerprints” of different impactor populations. C. Orgel, C. Riedel, G. Michael, H. Hiesinger; H. Becker.
- TRR 170-B1: Origin of fractionations of highly siderophile and siderophile volatile elements in lunar rocks and in the Earth. P. Gleissner, Z. Wang, C. Li, H. Becker.
- TRR 170-B2: Stable isotope fractionation of S, Te and Pd and the roles of core formation and late accretion on siderophile volatile elements in the Earth. F. Schmid, H. Becker, T. Grützner, S. Klemme, J. Hellmann, T. Kleine.
- TRR 170-C6: Formation and evolution of crust on early Earth. J. Schmidt, L. Noack.
- TRR 170-MGK „Integrated Research Training Group Planetary Sciences“ E. Lehmann, H. Becker.
- TRR 170-Z “Coordination Project” E. Lehmann, H. Becker.
- TRR 170 “Origin of Si and Fe isotope variations in enstatite chondrites” J. Sikdar, Y. Kadlag, M. Tatzel, H. Becker, D. Frick, J. Schüssler.
- TRR 170 “Highly siderophile and chalcophile elements in peridotites from the New Caledonia ophiolite” A. Secchiari, H. Becker, C. Li, P. Gleissner.
The element concentrations and isotopic composition of solutes in continental surface water and in suspended particles provide constraints on the fractionation processes and kinetics of chemical weathering. Isotopic fractionation of Li and Mg in these materials, in combination with other light element isotopes, has been used to constrain chemical weathering processes.
Light stable isotopes of O, H, C, S in surface water and in shells was also applied to constrain the sources and transport paths of atmospheric precipitation in Asia and in Central Europe and to test hypotheses on changes of atmospheric transport patterns with time.
- Lithium isotope composition of water from Tibetan lakes. M. Weynell, U. Wiechert, F. Riedel, A. Winkler. DFG SPP 1372 TIP (2011-2013).
- Li, Mg and non-metal isotope constraints on chemical weathering in Central Europe. C. Ullmann, C. Wutzke, F. Wilckens, U. Wiechert, K. Hammerschmidt, R. Romer, J. Schüssler.
- Stable isotope composition of water from Tibetan lakes. M. Weynell, U. Wiechert, F. Riedel, A. Winkler. DFG SPP 1372 TIP (2008-2010).
- Isotopic composition of atmospheric nitrate and sulfate. U. Wiechert.
The latet Neoproterozoic to Cambrian time marks the appearance of the animals and major changes in the oxygen content of the atmosphere-ocean system. In the context of the DFG research group “The Precambrian-Cambrian Biosphere (R)evolution: Insights from Chinese Microcontinents” (FOR 736), we have obtained geochronological constraints on black shale deposition using the Re-Os system. We also study the response of Neoproterozoic marine carbonates to diagenetic alteration and fluid flow in order to identify “primary” compositions in such rocks that yield information on the chemical and isotopic composition of seawater at that time.
- Sr, Nd and Li isotopes in carbonates of the Yangtze Platform and from Kazakhstan as tracers for the Ediacaran and Cambrian weathering history. S. Hohl, H. Becker, K. Hammerschmidt, U. Wiechert. Sub-project DFG FOR 736 (2011-2014) “The Precambrian-Cambrian Biosphere (R)evolution: Insights from Chinese Microcontinents”.
- Re-Os geochronology of black shales from the Neoproterozoic Doushantuo Formation, Yangtze platform, South China. B. Zhu, H. Becker, S.-Y. Jiang, D. Pi, M. Fischer-Gödde (2009-2011).
- U-Th-Pb Geochronology of Sediments from the Precambrian-Cambrian Transition, Yangtze Platform, China. W. Bäro, H. Becker, K. Hammerschmidt, Sub-project DFG FOR 736 (2008-2010) “The Precambrian-Cambrian Biosphere (R)evolution: Insights from Chinese Microcontinents”.
A major research focus lies on the processes that formed the early continental crust with tonalitic-trondhjemitic-granodioritic (TTG) composition. This includes the identification of Earth’s early geodynamic processes, characterization of the mafic rocks that melted to produce TTGs and the investigation of the pressure/temperature conditions of partial melting.
In addition, we study mantle-derived basalts, komatiites and Archean peridotites to place constraints on crust-mantle recycling and incompatible element depletion in mantle contemporaneous with crust formation processes. We apply major, trace element and Hf-Nd-Os isotope as well as highly siderophile element (HSE) analyses. These methods are combined with thermodynamic and numerical modeling to better characterize the framework of early Earth’s mantle and crustal evolution.
- Elucidating Eoarchean geodynamic processes by multiple sulfur isotopes DFG (2018-2021) J.E. Hoffmann, E.M. Schwarzenbach, H. Strauß, C. Münker, M.T. Rosing, M.J. Whitehouse SPP1833.
- Geochemistry of Eoarchean mantle peridotites from southern West Greenland DFG (2012-2018) J.E. Hoffmann, C. Münker, J. van de Löcht, H. Becker, H., Rosing, M.T., R. Kleinschrodt.
- Granitoid – greenstone relationships in the eastern Kaapvaal craton and implications for the early crustal evolution DFG (2014-2017) J.E. Hoffmann, K.P. Schneider, M. Boyet, D. Roerdink SPP1833.
- Siderophile and chalcophile elements in the Archean mantle-crust system CSC (2012-2016) C. Li, H. Becker, Z. Wang , I. Puchtel, E. Scherer, P. Sprung.
- Early Archaean crust-formation processes – constraints from the Ancient Gneiss Complex (Swaziland) and the Itsaq Gneiss Complex (West Greenland) DFG (2012-2014) J.E. Hoffmann, A. Kröner, J.-H. Yang, E. Hegner, C. Münker, E. Musese, L. Iiacceri, A. Hofmann, T.J. Nagel.
Important questions regarding the origin of the terrestrial planets and their building blocks are still open. Are primitive meteorites in our collections really the building blocks of Earth and other terrestrial planets? What processes are responsible for the depletion of volatile elements in the inner solar system? What is the origin and budget of volatile elements in the terrestrial planets? How much of the original volatile budget is lost during planetary growth? What can the Moon tell us about the early history of the Earth? Were the terrestrial planets affected by a “late heavy bombardment” of smaller bodies?
Chemical and isotopic studies of meteorites and lunar samples from the Apollo missions provide new constraints. This topic is closely related to research in TRR 170.
- Origin of the depletion of siderophile volatile elements in Earth, Mars and the aubrite parent body. Z. Wang, H. Becker (2013-2015) CRC, FUB, DFG.
- Cr isotope variations in components of chondrites. Y. Kadlag, H. Becker, DFG-SPP 1385 (2014-2015).
- Highly siderophile elements in ancient lunar impact rocks. P. Gleissner, H. Becker (2013-2015) DFG.
- Highly siderophile element abundances in components of chondrites. Y. Kadlag, H. Becker, DFG-SPP 1385 (2012-2013).
- Constraints on late accretion from S-Se-Te abundances in the earth’s mantle. Z. Wang, H. Becker CSC (2010-2013).
- Correlated nucleosynthetic anomalies in primitive meteorites. K. Rankenburg, H. Becker, K. Hammerschmidt DFG (2009-2010).
- Precise measurements of highly siderophile elements in ancient lunar impact rocks. M. Fischer-Gödde, H. Becker DFG (2008-2009).
- Highly Siderophile Elements as Tracers for Late Accretion. M. Fischer-Gödde, H. Becker, F. Wombacher, DFG-SPP 1115 (2006-2008).
Because we use lithophile (silicate-loving) siderophile (iron metal-loving) and chalcophile (sulfide-loving) element abundances in planetary materials to constrain planetary-scale processes in the early solar system (core formation, late accretion), it is necessary to understand the processes that can change abundances of these elements in magmatic and in surface processes. The formation of continental crust and recycling of oceanic crust and sediments via subduction have had substantial influence on the present-day composition and chemical evolution of the Earth’s mantle. These processes can be monitored by study of the variation of radiogenic isotope ratios (87Sr/86Sr, 143Nd/144Nd, 187Os/188Os, Pb isotopes) and trace element ratios in rocks derived from the Earth’s mantle (basalts, peridotites). We combine such tracers for study of the effects of partial melting and melt transport in the mantle and assimilation, fractional crystallization and mixing processes in the crust.
- Halogen extraction and determination of iodine and bromine abundances in geological reference materials J.E. Hoffmann, O. Jäger, T. John.
- Chalcophile element abundances in the Earth’s mantle. Z. Wang, H. Becker (2013-2016) CSC, DFG, FUB.
- Fractionation of highly siderophile elements in the lower oceanic crust. C. Meyer, H. Becker, DFG IODP-SPP (2011-2013).
- Highly siderophile element geochemistry of mantle pyroxenites. T. Gawronski, H. Becker, K. Hammerschmidt, DFG (2010-2013).
- Osmium isotopes and highly siderophile element fractionation in the massif-type anorthosites of the Mesoproterozoic Kunene Intrusive Complex, NW Namibia. P. Gleißner, K. Drüppel, H. Becker, DFG (2009-2010).
- Melt influx and the effects on Os-Sr-Nd isotopic systems and platinum group elements in Jurassic oceanic mantle (Totalp massif, Swiss Alps). D. van Acken, H. Becker, F. Wombacher, K. Hammerschmidt (w. R. Walker, UMD), NSF-EAR (2003-2005).
Several previous projects have focused on method development for microgeochronology for sampling of rocks and minerals on the sub-mm scale, in particular from ductile shear zones and the determination of cooling and uplift rates. Other projects have used Nd model ages and U-Pb dating of zircon.
- A Rb-Sr perspective on the timing of peak burial for the HP-UHP Akezayi metamorphic complex (Tianshan, NW China) L. Bayet, T. John, H. Becker, E. Hoffmann, P. Argand (2015-2017).
- Influence of microfabrics on transport of radiogenic and stable isotopes on the millimeter scale. M. Wegmann, K. Hammerschmidt DFG (2004-2005).
- Exhumation processes in the eastern Alps, S. Schneider, C. Rosenberg, K. Hammerschmidt, M. Handy. DFG (2006-2010).
- Geochronology and Precambrian continental growth in India, C. Dobmeier, S. Lütke, K. Hippe, K. Hammerschmidt, K. Mezger, M. Raith DFG.