The major theme of the collaborative research centre TRR 170 'Late Accretion onto Terrestrial Planets' is to understand the late growth history of the terrestrial planets, from the last giant collisions with Moon- to Mars-sized planetary embryos to the subsequent late bombardment with smaller objects. This period of planet formation is critically important for understanding the formation of the terrestrial planets and their chemical differentiation, and for constraining the parameters that controlled their subsequent evolution. To address these questions and improve our current understanding of the late growth history of the Earth, its Moon, and other terrestrial planets from 4.5 to 3.8 billion years ago, TRR 170 applies a multidisciplinary approach that combines expertise in geochemistry and petrology, remote sensing and planetary geology, and geodynamic and impact modelling. TRR 170's research programme 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. Specifically, we will (1) constrain the timing and distribution of basin-forming impacts on the Moon to improve basic parameters of the cratering chro-nology in the inner solar system, (2) quantify the mass, provenance and chemical composition of accreted materials between 4.5 and 3.8 billion years ago, (3) determine how the compositions of these materials were modified during accretionary impacts and magma degassing, (4) assess how accreted material was distrib-uted within the growing terrestrial planets and how it changed their subsequent evolution, and (5) develop quantitative models for the thermal evolution of the terrestrial planets, including the formation of and interac-tion between magma oceans, crust and early atmospheres in the relevant time interval. The combined results will refine our fragmentary understanding of several key processes during the early evolution of the terrestri-al planets, such as the role of giant impacts in volatile loss processes and core formation, the development and evolution of magma oceans, the transition to solid-state convection, homogenization of chemical and isotopic heterogeneities, and the cooling history of the terrestrial planets. Besides its scientific goals, TRR 170's dedicated integrated graduate programme will educate the next generation of planetary scientists, with a particular emphasis on the multidisciplinary character of modern planetary sciences.
DFG Programme
CRC/Transregios
Completed projects
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A01 - Chronometric investigations of ancient lunar impact rocks
(Project Heads
Becker, Harry
;
Scherer, Erik
)
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A02 - Reconstruction of the lunar crater production function and re-evaluation of its calibration to time
(Project Head
Hiesinger, Harald
)
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A03 - Ancient bombardment of the inner solar system - Reinvestigation of the "fingerprints" of different impactor populations
(Project Head
Kneissl, Thomas
)
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A04 - Formation and evolution of large impact basins on the Moo
(Project Heads
Oberst, Jürgen
;
Wünnemann, Kai
)
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A05 - Chronology of lunar crust formation and its relation to the age of the Moon
(Project Heads
Breuer, Doris
;
Kleine, Thorsten
;
Klemme, Ph.D., Stephan
)
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A06 - Comparative morphologies, ejecta plains, and ages of impact basins on the Moon and Mercury
(Project Heads
Hiesinger, Harald
;
Oberst, Jürgen
)
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B01 - Origin of the depletion of volatile metals in lunar rocks
(Project Head
Becker, Harry
)
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B02 - Stable isotope fractionation of S, Te, and Pd and the roles of core formation and late accretion on siderophile volatile elements in the Earth
(Project Heads
Becker, Harry
;
Fischer-Gödde, Mario
;
Klemme, Ph.D., Stephan
)
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B03 - Genetic heritage of late accretion
(Project Heads
Fischer-Gödde, Mario
;
Hiesinger, Harald
;
Kleine, Thorsten
;
Worsham, Ph.D., Emily
)
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B04 - The atmo- and hydrophile element (H and halogens) inventory of the Earth and Moon
(Project Heads
John, Timm
;
Klemme, Ph.D., Stephan
;
Stracke, Ph.D., Andreas
)
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B05 - Early-formed rare and unique meteorites and clasts in meteorite breccias
(Project Heads
Bischoff, Addi
;
John, Timm
)
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B06 - Comparing the (late) accretion history of Mars and Earth – timing, sources, dynamics
(Project Head
Burkhardt, Christoph
)
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B07 - Experimental and isotopic investigations of volatile element loss during magma degassing
(Project Heads
Burkhardt, Christoph
;
Klemme, Ph.D., Stephan
)
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B08 - Is the depletion of the moderately volatile elements in the Earth inherited from nebular processes?
(Project Heads
Becker, Harry
;
John, Timm
)
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C01 - Experimental constraints on volatile element partitioning during core formation on the terrestrial planets
(Project Head
Rohrbach, Arno
)
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C02 - Modelling giant impacts and the subsequent thermochemical evolution of liquid metal in a convecting magma ocean
(Project Heads
Hansen, Ulrich
;
Wünnemann, Kai
)
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C03 - 182W heterogeneities in Earth's mantle – early differentiation, late accretion, and core-mantle interaction
(Project Heads
Hansen, Ulrich
;
Kleine, Thorsten
;
Stracke, Ph.D., Andreas
)
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C04 - From the Moon-forming impact to the era of late bombardment: the thermochemical evolution of the early Earth-Moon system
(Project Heads
Breuer, Doris
;
Hansen, Ulrich
;
Wünnemann, Kai
)
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C05 - Early interior-surface-atmosphere interactions on the terrestrial planets
(Project Heads
Rauer, Heike
;
Sohl, Frank
;
Wünnemann, Kai
)
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C06 - Crust formation and outgassing on early Earth and Mars
(Project Heads
Noack, Lena
;
Sohl, Frank
)
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INF - TRR 170 data management - building a planetary data portal
(Project Head
Becker, Harry
)
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MGK - Integrated Research Training Group "Planetary Sciences"
(Project Heads
Becker, Harry
;
Hiesinger, Harald
;
Kleine, Thorsten
)
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Z - Central Task of the Collaborative Research Center
(Project Heads
Hiesinger, Harald
;
Kleine, Thorsten
)
