Long term structural development and landscape evolution of eastern Dronning Maud Land, and implications for the geological evolution of the Weddell Sea region
Final Report Abstract
Sør Rondane is located in a key location of the East Antarctic continental margin, where the so far unknown suture between East and West Gondwana has been presumed to pass through Dronning Maud Land (DML). It also occupies a crucial position at the Karoo-Maud Plume between Antarctica, Africa/ Madagascar and India/ Sri Lanka, and therefore represents a key locus for our understanding of both the assemblage and dispersal of Gondwana. The composite project studied the long-term geological evolution of Sør Rondane by means of geophysical (gravimetric and aoeromagnetic), structural geology, petrological, geochemical, geochronological, and thermochronological data. Thereby, the focus of sub-project LA was on the crustal structural evolution with regard to amalgamation and fragmentation of the supercontinents Rodinia and Gondwana and to identify the locus and nature of the suture between East and West Gondwana by a combined geophysical-geological multimethodological approach. The results contributed particularly to the key targets identified by SCAR and the National Committee SCAR-IASC and provided new data to the SCAR ADMAP Expert Group and CGG Action Group. Crucial results of project LA are (i) high-resolution gravimetric and aeromagnetic mapping and classification of the continental crust of DML, (ii) the record of the kinematic and tectonic inventory of Sør Rondane including assessment of the regional Main Shear Zone and evaluation of the intra- Gondwanan suture in eastern DML, (iii) an improved reconstruction of the orogenetic processes in the former East African Antarctic Orogen (timing, style of deformation, associated magmatism, degree of metamorphism etc.) and conception of a new terrane model (TOAST), and (iv) a contribution to our understanding of the Gondwanan breakup and the development of the passive continental margin near the triple junction Antarctica – Africa/Madagascar – India. The latter aspect links the two projects, with project LI concentrating on the course of Gondwana breakup, the opening of the South Atlantic Ocean and the establishment of the present plate configuration, the regional exhumation and uplift history, and the long-term landscape evolution of Sør Rondane and the Shackleton Range west of DML. Main results of this project was the recognition that the basement of both regions was subjected to long-lasting crustal extension and consequently buried beneath sedimentary basin deposits during the Mesozoic and early Cenozoic. Final uplift and basin inversion appear to be related to the rifting of the Weddell Sea (Shackleton Range) and to Gondwana breakup and passive margin evolution (SøR Rondane). The combination of a wide spectrum of different but complementary methods overcomes a classical problem that is not restricted to Antarctica: to test hypotheses and to develop new concepts by linking high-resolution geophysical data sets with geological information. The combination of multiple, different methodological approaches for the common goal to reconstruct the geological history of Sør Rondane in the context of the Gondwana cycle culminates in coherent models for both Gondwana accretion and dispersal outlined in synoptic review sections of two PhD theses.
Publications
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(2014): New detailed aeromagnetic and geological data of eastern Dronning Maud Land: Implications for refining the tectonic and structural framework of Sør Rondane, East Antarctica. – Precambrian Research, 245, 174-185
Mieth, M., Jacobs, J., Ruppel, A., Damaske, D., Läufer, A. & Jokat, W.
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(2015): Early Neoproterozoic metagabbro-tonalite-trondhjemite of Sør Rondane (East Antarctica): Implications for supercontinent assembly. – Precambrian Research, 259, 189-206
Elburg, M., Jacobs, J., Andersen, T., Clark, C., Läufer, A., Ruppel, A., Krohne, N. & Damaske, D.
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(2015): The Main Shear Zone in Sør Rondane, East Antarctica: Implications for the late-Pan-African tectonic evolution of Dronning Maud Land. – Tectonics, 34, 1290-1305
Ruppel, A., Läufer, A. L., Jacobs, J., Elburg, M., Krohne, N., Damaske, D. & Lisker, F.
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(2015): Two distinct Late Mesoproterozoic/Early Neoproterozoic basement provinces in central/eastern Dronning Maud Land, East Antarctica: the missing link, 15- 21°E. – Precambrian Research, 265, 249-272
Jacobs, J., Elburg, M., Läufer, A., Kleinhanns, I.C., Henjes-Kunst, F., Estrada, S., Ruppel, A., Damaske, D., Montero, P. & Bea, F.
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(2016): One hundred and fifty million years of Pan-African magmatism in the Sør Rondane Mountains (East Antarctica): Implications for Gondwana assembly. – The Journal of Geology, 124, 1-26
Elburg, M., Andersen, T., Jacobs, J., Läufer, A., Ruppel, A., Krohne, N. & Damaske, D.
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(2016): The Shackleton Range: an alien block at the rim of Gondwana? – Geological Magazine, 155, 841-864
Krohne, N., Lisker, F., Kleinschmidt, G., Klügel, A., Läufer, A. & Spiegel, C.
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(2017): Cryptic sub-ice geology revealed by a U-Pb zircon study of glacial till in Dronning Maud Land, East Antarctica. – Precambrian Research, 294, 1-14
Jacobs, J., Opas, B., Elburg, M., Läufer, A., Estrada, S., Ksienzyk, A.K., Damaske, D., & Hofmann, M.
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(2018): Erosion at extended continental margins: Insights from new aerogeophysical data in eastern Dronning Maud Land. – Gondwana Research, 63, 105-116
Eagles, G., Karlsson, N., Ruppel, A., Steinhage, D., Jokat, W. & Läufer, A.
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(2018): New geophysical data from a key region in East Antarctica: estimates for the spatial extent of the Tonian Oceanic Arc Super Terrane (TOAST). – Gondwana Research, 59, 97-107
Ruppel, A., Jacobs, J., Eagles, G., Läufer, A. & Jokat, W.
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(2019): Deep glacial troughs and stabilizing ridges unveiled beneath the margins of the Antarctic ice sheet. – Nature Geoscience
Morlighem, M., Rignot, E., Binder, T., Blankenship, D., Drews, R., Eagles, G., Eisen, O., Ferraccioli, F., Forsberg, R., Fretwell, P., Goel, V., Greenbaum, J.S., Gudmundsson, H., Guo, J., Helm, V., Hofstede, C., Howat, I., Humbert, A., Jokat, W., Karlsson, N.B., Lee, W.S., Matsuoka, K., Millan, R., Mouginot, J., Paden, J., Pattyn, F., Roberts, J., Rosier, S., Ruppel, A., Seroussi, H., Smith, E.C., Steinhage, D., Sun, B., van den Broeke M.R., van Ommen, T.D., van Wessem, M. & Young, D.A.
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(2019): New U-Pb-Hf-O zircon analyses of the Schirmacher Oasis, East Antarctica, and significance for the Neoproterozoic geodynamic evolution of easternmost Kalahari. – Precambrian Research
Jacobs, J., Mikhalsky, E., Henjes-Kunst, F., Elburg, M., Läufer, A., Wang, C.-C., Thomas, R.J., Estrada, S. & Skublov, S.G.
