EGU2020-10678, updated on 12 Jun 2020
https://doi.org/10.5194/egusphere-egu2020-10678
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Mineral assemblages and xenolith cargo in the Storkwitz carbonatite (Delitzsch Complex, Germany)

Hripsime Gevorgyan1,2, Sascha Schmidt1, Ilja Kogan1,3, and Manuel Lapp4
Hripsime Gevorgyan et al.
  • 1Geological Institute, TU Bergakademe Freiberg, 09599 Freiberg, Germany (hripsime.gevorgyan@geology.am)
  • 2Institute of Geological Sciences, National Academy of Sciences of Armenia, 0019 Yerevan, Armenia
  • 3Institute of Geology and Petroleum Technologies, Kazan Federal University, 420008 Kazan, Russia
  • 4Geological Survey of Saxony, 09599 Freiberg, Germany

The multi-compositional carbonatite body of Storkwitz is one of several purported diatremes of the Late Cretaceous Delitzsch Complex, which comprises carbonatites and ultramafic lamprophyres emplaced into a heterogeneous series of volcanic and sedimentary rocks of Precambrian to Early Permian age (Krüger et al., 2013; Seifert et al., 2000). The Late Cretaceous peneplain is covered with about one hundred meters of Tertiary soft rock. According to Röllig et al. (1990), the Delitzsch Complex developed in six stages: (i) hidden intrusion of a dolomite carbonatite (rauhaugite) that led to the formation of a fenite aureole; (ii) ultramafic and alkaline lamprophyre intrusion (alnöite, aillikite, monchiquite); (iii) formation of beforsitic diatremes (intrusive breccias), including xenoliths of dolomite carbonatite and ultramafic lamprophyre; (iv) ultramafic and alkali lamprophyres (dykes within diatremes of 3rd stage); (v) formation of beforsite and (vi) alvikite dykes.

The Storkwitz carbonatite is mainly characterized by beforsitic breccias containing abundant angular xenoliths of metasediments form the complete underlying stratigraphic succession, metamorphic and igneous rocks, as well as rounded xenoliths of ultramafic lamprophyre, rauhaugite, fenite, and glimmerite, which suggest the existence of a deep-seated carbonatite pluton (Seifert et al., 2000). It is remarkable that the fenites exhibit a different degree of fenitization and show occurrence of phlogopite in the strongly fenitized samples. The matrix of the Storkwitz carbonatite is mainly composed of ankerite and calcite/siderite, which corresponds to ferro- or silico-carbonatites.

Detailed petrographical observations on extensive drill core material, new analyses and a reinterpretation of published data confirm the existence of compositional variation and zonation within the carbonatite body that reflect independent crystallization history and formation due to multiple magmatic events. The different generations of apatite and phlogopite from the early stage of the plutonic dolomite carbonatite through the late-stage beforsite dykes and fine-grained calcite carbonatite veins shed light on the crystallization history and magma development of carbonatites.

 

References

 

Krüger, J.C., Romer, R.L., Kämpf, H., 2013. Late Cretaceous ultramafic lamprophyres and carbonatites from the Delitzsch Complex, Germany. Chemical Geology, 353, 140-150.

Röllig, G., Viehweg, M., Reuter, N., 1990. The ultramafic lamprophyres and carbonatites of Delitzsch/GDR. Zeitschrift für Angewandte Geologie, 36, 49-54.

Seifert, W., Kämpf, H., Wasternack, J., 2000. Compositional variation in apatite, phlogopite and other accessory minerals of the ultramafic Delitzsch complex, Germany: implication for cooling history of carbonatites. Lithos, 53, 81-100.

How to cite: Gevorgyan, H., Schmidt, S., Kogan, I., and Lapp, M.: Mineral assemblages and xenolith cargo in the Storkwitz carbonatite (Delitzsch Complex, Germany), EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-10678, https://doi.org/10.5194/egusphere-egu2020-10678, 2020

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