Archean detrital zircon's age at the active East-volcanic zone of Kamchatka

Yuri Kostitsyn, Elena Belousova

Research output: Contribution to journalMeeting abstract

Abstract

We present results of U-Pb isotopic and trace-element geochemical studies of detrital zircons collected in the area of Quaternary and the modern volcanic activity at the East-Volcanic Zone of the Kamchatka peninsula, Russia: Karymsky, Maly Semiachik, Central Semiachik, Uzon, Kihpinych and Krasheninnikov volcanoes located within the area of the Kronotsky National park. Pre-Quaternary volcanic or sedimentary rocks are not known in the area of sampling and there are no pre-Cretaceous rocks exposed in the Kamchatka peninsula.

The main goal of the study is to test a hypothesis of older basement rocks existence under the volcanoes in the melting area and to assess age of these source rocks. Recovered detrital zircons were studied by LA-ICP-MS technique using Element-XR ICP-MS and UP-213 laser ablation system.

Many of zircons were too young (much less than 1 Ma) to get quantitatively measurable U-Pb ages using LA-ICP-MS method, however a number of robust older age clusters were discovered. The most intriguing result is that more than a hundred zircon grains from three samples collected near the Karymskoe Lake produced a good discordia with ages 1940±50 Ma and 2980±20 Ma. Other less populated clusters are close to 330 Ma, 78 Ma and 2.4 Ma.

There is a correlation found between age and trace element composition of the studied zircons: older zircons have higher Th/U ratios and more pronounced Eu anomaly than younger populations.

Obtained results reveal existence of the Achaean basement (ca 2980 Ma) under the East-Volcanic Zone of the Kamchatka peninsula as well as younger, particularly Cretaceous rocks that are known only within the Central Kamchatka Range.
Original languageEnglish
Pages (from-to)A534-A534
Number of pages1
JournalGeochimica et Cosmochimica Acta
Volume74
Issue number12
Publication statusPublished - Jun 2010
EventGoldschmidt Conference (20th : 2010) - Knoxville, United States
Duration: 13 Jun 201018 Jun 2010

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