On the chemical composition and possible origin of Na–Cr-rich clinopyroxene in silicocarbonatites from Samalpatti, Tamil Nadu, South India
The result's identifiers
Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00025798%3A_____%2F18%3A00000103" target="_blank" >RIV/00025798:_____/18:00000103 - isvavai.cz</a>
Alternative codes found
RIV/00216224:14310/18:00103453 RIV/00216208:11310/18:10392764
Result on the web
<a href="http://www.mdpi.com/journal/minerals" target="_blank" >http://www.mdpi.com/journal/minerals</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.3390/min8080355" target="_blank" >10.3390/min8080355</a>
Alternative languages
Result language
angličtina
Original language name
On the chemical composition and possible origin of Na–Cr-rich clinopyroxene in silicocarbonatites from Samalpatti, Tamil Nadu, South India
Original language description
Mineralogical and chemical data are presented for a suite of Na–Cr-rich clinopyroxenes associated with chromite, winchite (sodium-calcium amphibole), titanite and calcite in Mg-Cr-rich silicocarbonatites from the Samalpatti carbonatite complex, Tamil Nadu, South India. The Mg-Cr-rich silicocarbonatites occur as 10–30 cm large enclaves in pyroxenites. The chemical composition of the pyroxenes differs among individual enclaves, with variable proportions of diopside, kosmochlor and jadeite-aegirine end-members. These compositions fill a previously unoccupied space in the kosmochlor-diopside-jadeite+aegirine ternary plot, indicating a distinct origin of kosmochlor-rich pyroxene compared with previous findings from diverse settings. The Na–Cr-rich clinopyroxene has low sigmaREE = 9.2 ppm, with slight enrichment in LREE (LaN = 7), coupled with low HREE (YbN = 0.6), and flat HREE, paralleled by a significant fractionation of Nb/Ta (2408) and Th/U (26.5). Sodic metasomatism (fenitization) associated with either carbonatite emplacement at shallow levels or during carbonatite ascent through the upper mantle most likely was the major process operating in the area. We suggest two scenarios of the formation of Na–Cr-rich pyroxene: (1) from mantle-derived chromian mineral phases (spinel and/or garnet) through fenitization, with subsequent corrosion by growing winchite due to volatile influx; (2) via metasomatic reaction of Cr-rich garnet in mantle peridotite due to reaction with Na-rich carbonatite melt. Collectively, the appearance of kosmochlor may play an important role in deconvolving metasomatic processes, and fenitization in particular. If combined with petrologic experiments, it could improve our understanding of the origin and subsequent history of chemical signatures of carbonate-rich materials in the mantle.
Czech name
—
Czech description
—
Classification
Type
J<sub>imp</sub> - Article in a specialist periodical, which is included in the Web of Science database
CEP classification
—
OECD FORD branch
10504 - Mineralogy
Result continuities
Project
<a href="/en/project/GA15-08583S" target="_blank" >GA15-08583S: Role of carbonatites for Zr–Hf–Nb–Ta and highly siderophile element budgets in the Earth’s mantle – combined stable–radiogenic isotope approach</a><br>
Continuities
P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)
Others
Publication year
2018
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů
Data specific for result type
Name of the periodical
Minerals
ISSN
2075-163X
e-ISSN
—
Volume of the periodical
8
Issue of the periodical within the volume
8: 355
Country of publishing house
CH - SWITZERLAND
Number of pages
14
Pages from-to
nestránkováno
UT code for WoS article
000443257900045
EID of the result in the Scopus database
2-s2.0-85052622920