|1Artemenko, GV |
1 M.P. Semenenko Institute of Geochemistry, Mineralogy and Ore-Formation of the NAS of Ukraine, Kyiv
|Dopov. Nac. akad. nauk Ukr. 2020, 4:66-76|
Sedimentary rocks of the Trinity series are observed on the Antarctic Peninsula from the northern part to the south for about 500 km. Determining their sedimentation area and formation conditions is of great importance for reconstructing the boundaries of the Gondwana supercontinent. Sedimentary rocks of the Trinity series ha ve been fully studied in the northern part of the Antarctic Peninsula and much less in the southern part of their distribution area. We studied the thickness of turbidites in the eastern part of the Lahille island. Turbidites are represented by intercalation of layers of quartz graywackes, thicknesses from the first centimeters to 30 cm and argillites, thicknesses from the first centimeters up to 15 cm. In quartz graywackes, fragments are predominantly monocrystalline, less often fragments of rocks of various shapes - angular, acute-angled, sharply irregular in shape. The size of the debris varies from 0.03 to 0.6 mm. Argillites consist of a host mass and oolite-like formations included in it, which are composed of cryptogranular minerals. A study of the mineral composition of argillite by X-ray diffraction analysis showed that the predominant minerals therein are quartz with a subordinate amount of biotite and an admixture of albite and some ore minerals. A very low degree of change in the primary sedimentary rocks of the Trinity series in the southern part of the area of their distribution — in the conditions of late catagenesis — early metagenesis according to the scale by N.V. Logvinenko and L.V. Orlova was established. In contrast to this region, sedimentary rocks of the Trinity series in the northern part of the Antarctic Peninsula are metamorphosed under the conditions of prehnite-pumpellyite, pumpellyite-actinolite and green shale facies. It has been established that, in the area of sedimentary rock demolition in the area of the Lahille island, the acidic and medium igneous rocks of the sodium composition of the crustal genesis are dominant and, in a subordinate amount, there were also basic rocks. According to the data obtained, sedimentary rocks of the Trinity series of the study area were formed in the upper part of the continental slope.
|Keywords: Antarctic Peninsula, Gondwana, mudstone, oolitic structures, petrofacies, quartz greywacke, rare earth elements, sedimentation area, Trinity series, turbidites|
1. Adie, R. J. (1957). The petrology of Graham Land: III. Metamorphic rocks of the Trinity Peninsula series. London: HMSO. (Falkland Islands Dependencies Survey, Scientific Reports, No. 20).
2. Burton-Johnson, A., & Riley, T. R. (2015). Autochthonous v. accreted terrane development of continental margins: a revised in situ tectonic history of the Antarctic Peninsula. J. Geol. Soc., 172, pp. 822-835. Doi: https://doi.org/10.1144/jgs2014-110
3. Vaughan, A. P. M. & Storey, B. C. (2000). The eastern Palmer Land shear zone: a new terrane accretion model for the Mesozoic development of the Antarctic Peninsula. J. Geol. Soc. London, 157, pp. 1243-1256. Doi: https://doi.org/10.1144/jgs.157.6.1243
4. Smellie, J. L., Roberts, B. & Hirons, S. R. (1996). Very low- and low-grade metamorphism in the Trinity Peninsula Group (Permo-Triassic) of northern Graham Land, Antarctic Peninsula. Geol. Mag., 133, pp. 583-594. Doi: https://doi.org/10.1017/S001675680000786X
5. Barbeau, D. L., Davis, J. T., Murray, K. E., Valencia, V., Gehrels, G. E., Zahid, K. M. & Gombosi, D. J. (2010). Detrital-zircon geochronology of the metasedimentary rocks of north-western Graham Land. Antarct. Sci., 22, pp. 65-78. Doi: https://doi.org/10.1017/S095410200999054X
6. Willan, R. C. R. (2003). Provenance of Triassic-Cretaceous sandstones in the Antarctic Peninsula: implications for terrane models during Gondwana breakup. J. Sediment. Res., 73, pp. 1062-1077. Doi: https://doi.org/10.1306/050103731062
7. Bradshaw, J. D., Vaughan, P. M., Millar, I. L., Flowerdew, M. J., Trouw, R. A. J., Fanning, C. M. & Whitehouse, M. J. (2012). Permo-Carboniferous conglomerates in the Trinity Peninsula Group at Viev Point, Antarctic Peninsula: sedimentology, geochronology and isotope evidence for provenance and tectonic setting in Gondwana. Geol. Mag., 149, No. 4, pp. 626-644. Doi: https://doi.org/10.1017/S001675681100080X
8. Castillo, P., Lacassie, J.P., Augustsson, C. & Herve, F. (2014). Petrography and geochemistry of the Car boniferous–TriassicTrinity Peninsula Group, West Antarctica: implications for provenance and tectonic setting. Geol. Mag., 152 No. 4, pp. 575-588. Doi: https://doi.org/10.1017/S0016756814000454
9. Pettijon, F., Potter, P. & Seaver, R. (1976). Sands and sandstones. Moscow: Мir (in Russian).
10. Shutov, V. D. (1967). Classification of sandstones. Litologiya i poleznyie iskopaemyie, No. 5, pp. 86-102 (in Russian).
11. Dickinson, W. R., Berad, L. S., Brakenridge, G. R., Erjavec, J. L., Ferguson, R. C., Inman, K. F., Knepp, R. A., Lindberg, F. A. & Ryberg, P. T. (1983). Provenance of North American Phanerozoic sandstones in relation-totectonic-setting. GSA Bulletin, 94, No. 2, pp. 222-235. Doi: https://doi.org/10.1130/0016-7606(1983)94<222:PONAPS>2.0.CO;2
12. Smellie, J. L. (1991). Stratigraphy, provenance and tectonic setting of (?) Late Palaeozoic-Triassic sedimentary sequences in northern Graham Land and South Scotia Ridge. In Thomson, M. R. A., Crame, J. A. & Thomson, J. W. (Eds.). Geological Evolution of Antarctica (pp. 411-417). Cambridge: Cambridge University Press.
13. Bracciali, L., Marroni, M., Pandolfi, L. & Rocchi, S. (2007). Geochemistry and petrography of Western Tethys Cretaceous sedimentary covers (Corsica and Northern Apennines): From source areas to configuration of margins. Sedimentary Provenance and Petrogenesis: Perspectives from Petrography and Geochemistry Geological Society of America, Special Paper 420 (pp. 73-93). Doi: https://doi.org/10.1130/2006.2420(06)
14. Logvinenko, N. V. & Orlova, L. V. (1987). Formation and change of sedimentary rocks on the continent and in the ocean. Leningrad: Nedra (in Russian).