J 2016

Rhenium–osmium isotopes in pervasively metasomatized mantle xenoliths from the Bohemian Massif and implications for the reliability of Os model ages.

KOCHERGINA, Yulia V., Lukáš ACKERMAN, Vojtěch ERBAN, Magda MATUSIAK-MAŁEK, Jacek PUZIEWICZ et. al.

Basic information

Original name

Rhenium–osmium isotopes in pervasively metasomatized mantle xenoliths from the Bohemian Massif and implications for the reliability of Os model ages.

Authors

KOCHERGINA, Yulia V. (203 Czech Republic), Lukáš ACKERMAN (203 Czech Republic), Vojtěch ERBAN (203 Czech Republic), Magda MATUSIAK-MAŁEK (616 Poland), Jacek PUZIEWICZ (616 Poland), Patricie HALODOVÁ (203 Czech Republic), Petr ŠPAČEK (203 Czech Republic, belonging to the institution), Jakub TRUBAČ (203 Czech Republic) and Tomáš MAGNA (203 Czech Republic)

Edition

Chemical Geology, Amsterdam, Elsevier, 2016, 0009-2541

Other information

Language

English

Type of outcome

Článek v odborném periodiku

Field of Study

Geochemistry

Country of publisher

Netherlands

Confidentiality degree

není předmětem státního či obchodního tajemství

Impact factor

Impact factor: 3.347

RIV identification code

RIV/00216224:14310/16:00088679

Organization unit

Faculty of Science

UT WoS

000374658500008

Keywords in English

Sub-continental lithospheric mantle; Peridotite xenolith; Bohemian Massif; Ohře/Eger rift; Os isotopes; Re–Os; Depletion age

Tags

Změněno: 13/4/2017 21:09, Ing. Andrea Mikešková

Abstract

V originále

Peridotite xenoliths brought to the surface by basaltic lavas attest to a variety of mantle processes, including partial melting, melt percolation or refertilization. The whole rock Re–Os concentrations and Os isotopic compositions were determined for 30 xenoliths collected from 11 localities across the northern Bohemian Massif in order to evaluate the Os model ages and attempt to relate the results to major crustal tectonic events during the history. Most samples were affected by variable extent of metasomatic overprint, which is commonly paralleled by very low Os concentrations (<1 ppb). Rhenium concentrations in the whole suite are below the primitive mantle value. A subset of samples shows evidence for Re addition from host basaltic rocks, consistent with the presence of abundant melt pockets with secondary sulphides. The 187Os/188Os ratios range from 0.1162 to 0.1330 and cannot be directly related to individual mantle domains, implying the inability of more recent tectonic events to reset the original Os isotopic systematics. The calculated mantle extraction ages (TMA) range from <0.1 to 2.1 Ga, whereas future ages obtained for nine samples indicate metasomatic overprints. The Re depletion ages (TRD) varybetween <0.1 and ~1.6 Ga. However, the TRD is not well suited for direct comparisonwith crustal ages because it represents a minimum age limit rather than specific age estimate. Therefore, a modified model age (TRDII) was calculated assuming a non-zero Re content during the pre-metasomatic stage and using a composition of the most depleted sample in our suite. A prominent peak in the calculated TRDII ages ranges between 0.5 and 0.6 Ga which corresponds to the Cadomian orogenic cycle.

Links

GAP210/12/0573, research and development project
Name: Pozdně kvartérní seismogenní zlomová aktivita a související vývoj sedimentačních pánví ve východní části Českého masívu
Investor: Czech Science Foundation