Portal de Periódicos da CAPES

Potassium-argon age measurements on dolerites from Antarctica and South Africa

1963; American Geophysical Union; Volume: 68; Issue: 5 Linguagem: Inglês

10.1029/jz068i005p01535

2156-2202

Ian McDougall,

Paleontology and Stratigraphy of Fossils

Journal of Geophysical Research (1896-1977)Volume 68, Issue 5 p. 1535-1545 Potassium-argon age measurements on dolerites from Antarctica and South Africa Ian McDougall, Ian McDougallSearch for more papers by this author Ian McDougall, Ian McDougallSearch for more papers by this author First published: 1 March 1963 https://doi.org/10.1029/JZ068i005p01535Citations: 121AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat Abstract Dolerites intrusive into flat-lying Carboniferous to Triassic strata crop out extensively in Antarctica, South Africa, Tasmania, and South America. K-Ar measurements give ages ranging from 147 to 163 m.y. for the Antarctica dolentes and from 154 to 190 m.y. for the South African (Karroo) dolerites. Hence in South Africa emplacement of dolente commenced early in the Jurassic and continued into the Middle Jurassic, at which time intrusion of dolerite magma occurred in Tasmania, Antarctica, and possibly South America also; this major event may be related to the postulated breakup of Gondwanaland. Three dolerites that are intrusive into pre-Karroo rocks in South Africa yield Precambrian ages. Measurements were made on whole-rock samples, plagioclase, pyroxene, and hornblende, further demonstrating that materials of low potassium content can give reliable ages. No evidence was found for excess radiogenic argon in any of the pyroxenes measured. References Blignaut, J. J. G., F. J. J. Furter, The northern Natal coalfield, S. African Geol. Surv. Coal Mem., 1, 1–336, 1940. Blundell, D. J., P. J. Stephenson, Palaeomagnetism of some dolerite intrusions from the Theron Mountains and Wichaway Nunataks, Antarctica, Nature, 184, 1860, 1959. Boocock, C., Discussion of paper by Eales (1959), Trans. Proc. Geol. Soc. S. Africa, 62, 111, 1959. Browne, W. R., The dolerites of King George Land and Adelie Land, Australian Antarctic ped., 1911-1914, Repts., Ser. A, 3, 245–258, 1923. Bull, C., E. Irving, The palaeomagnetisra of some hypabyssal intrusive rocks from South Victoria Land, Antarctica, Geophys. J., 3, 211–224, 1960. Bull, C., E. Irving, I. Willis, Further palaeomagnetic results from South Victoria Land, Antartica, Geophys. J., 6, 320–336, 1962. Carey, S. W., A tectonic approach to continental drift, Continental Drift—A Symposium, 177–335University of Tasmania, Hobart, 1958. Debenham, F., The sedimentary rocks of South Victoria Land, British Antarctic Exped., 1910, Geology, 1, 101–119, 1921. Du Toit, A. L., Our Wandering Continents, 366, Oliver and Boyd, London, 1937. Du Toit, A. L., Geology of South Africa 3rd ed., 611, Oliver and Boyd, London, 1954. Eales, H. V., The Khale dolerite sheet, Trans. Proc. Geol. Soc. S. Africa, 62, 81–111, 1959. Edwards, A. B., Differentiation of the dolerites Tasmania, J. Geol., 50, 451–480579–610, 1942. Edwards, W. N., The occurrence of Glossopteris in the Beacon sandstone of the Ferrar Glacier, South Victoria Land, Geol. Mag., 65, 323–327, 1928. Erickson, G. P., J. L. Kulp, Potassium-argon measurements on the Palisades sill, New Jersey, Bull. Geol. Soc. Am., 72, 649–652, 1961. Evernden, J. F., J. R. Richards, Potassium-argon ages in eastern Australia, J. Geol. Soc. Australia, 9, 1–50, 1962. Evernden, J. F., G. H. Curtis, R. W. Kistler, J. Obradovich, Argon diffusion in glauconite, microcline, sanidine, leucite, and phlogopite, Am. J. Sci., 258, 583–602, 1960. Ferrar, H. T., Report on the field geology of the region explored during the “Discovery” Antarctic Expedition, 1901–4, Nat. Antarctic Exped., 1901–4, Natural History, 1, 1–160, 1907. Gould, L., Structure of the Queen Maud Mountains, Antarctica, Bull. Geol. Soc. Am., 46, 973–983, 1935. Graham, K. W. T., A. L. Hales, Palaeomagnetic measurements on Karroo dolerites, Advances in Physics, 6, 140–161, 1957. Harrington, H. J., Nomenclature of rock units in the Ross Sea region, Antarctica, Nature, 182, 290, 1958. Hart, S. R., The use of hornblendes and pyroxenes for K-Ar dating, J. Geophys. Res., 66, 2995–3001, 1961. Hart, S. R., R. T. Dodd Jr., Excess radiogenic argon in pyroxenes, J. Geophys. Res., 67, 2998–2999, 1962. Irving, E., The magnetisation of the Mesozoic dolerites of Tasmania, Papers Proc. Roy. Soc. Tasmania, 90, 157–168, 1956. Jaeger, J. C., The temperature in the neighborhood of a cooling intrusive sheet, Am. J. Sci., 255, 306–318, 1957. Jaeger, J. C., Temperatures outside a cooling intrusive sheet, Am. J. Sci., 257, 44–54, 1959. Kulp, J. L., Geologic time scale, Science, 133, 1105–1114, 1961. Long, W. E., Sedimentary rocks of the Buckeye Range, Horlick Mountains, Antarctica, Science, 136, 319–321, 1962. Mawson, D., Sedimentary rocks, Australasian Antarctic Exped., 1911–14, Sci. ReptsSer. A, 4, Geology, 345–367, 1940. McDougall, I., Determination of the age of a basic igneous intrusion by the potassium-argon method, Nature, 190, 1184–1186, 1961. McDougall, I., Differentiation of the Tasmanism dolerites, Bull. Geol. Soc. Am., 73, 279–316, 1962. McKelvey, B. C., P. N. Webb, Geological investigations in South Victoria Land, Antarctica, 2, Geology of upper Taylor Glacier region, New Zealand J. Geol. Geophys., 2, 718–728, 1959. McKelvey, B. C., P. N. Webb, Geological reconnaissance in Victoria Land, Antarctica, Nature, 189, 545–547, 1961. Mountain, E. D., The dikes of the Transkei Gaps, Trans. Geol. Soc. S. Africa, 46, 55–73, 1943. Nicolaysen, L. O., J. W. L. deVilliers, A. J. Burger, F. W. E. Strelow, New measurements relating to the absolute age of the Transvaal system and of the Bushveld igneous complex, Trans. Proc. Geol. Soc. S. Africa, 61, 137–163, 1958. Poldervaart, A., The petrology of the Elephant's Head dike and the New Amalfi sheet (Matatiele), Trans. Roy. Soc. S. Africa, 30, 85–119, 1944. Poldervaart, A., Karroo dolerites and basalts in the eastern part of the Bechuanaland Protectorate, Trans. Proc. Geol. Soc. S. Africa, 55, 125–130, 1952. Reynolds, J., High sensitivity mass spectrometer for noble gas analysis, Rev. Sci. Instr., 27, 928–934, 1956. Schreiner, G. D. L., Age of a Pilansberg dyke of palaeomagnetic significance, Nature, 181, 1330–1331, 1958a. Schreiner, G. D. L., Comparison of the 87Rb — > 87Sr ages of the red granite of the Bushveld complex from measurements on the total rock and separated mineral fractions, Proc. Roy. Soc., London, A, 245, 112–117, 1958b. Seward, Antarctic fossil plants, British Antarctic Exped., 1910, Natural History Rept., Geology1, 1–49, 1914. Starik, I. Ye., A. Ya. Krylov, M. G. Ravich, Yu. I. Silin, The absolute ages of East Antarctica rocks, Ann. N. Y. Acad. Sci., 91, 576–582, 1961. Truswell, J. F., A petrological study of dolerite sills in the Jagersfontein diamond mine, Orange Free State, Trans. Proc. Roy. Soc. S. Africa, 409–416, 1955. Turner, F. J., J. Verhoogen, Igneous and Metamorphic Petrology 2nd ed., 694, McGraw-Hill Book Co., New York, 1960. Walker, F., A. Poldervaart, Karroo dolerites of the Union of South Africa, Bull. Geol. Soc. Am., 60, 591–706, 1949. Webb, P. N., B. C. McKelvey, Geological investigations in South Victoria Land, Antarctica, 1, Geology of Victoria Dry Valley, New Zealand J. Geol. Geophys., 2, 120–136, 1959. Wegener, A., The origin of continents and oceans, translated from 3rd German ed. by J. G. A. Skerl,, 212 pp., Methuen, London,1924. Woodward, A. S., Fish remains from the Upper Old Red Sandstone of Granite Harbour, Antarctica, British Antarctic Exped., 1910, Natural History Rept., Geology1, 51–62, 1921. Citing Literature Volume68, Issue51 March 1963Pages 1535-1545 ReferencesRelatedInformation