Petrogenesis of shergottite meteorites inferred from minor and trace element microdistributions

Magmatic volatiles are critically important in the petrogenesis of igneous rocks but their inherent transience hampers the identification of their role in magmatic and metasomatic processes. For example, while the role of magmatic volatiles in porphyry copper systems is relatively well understood, the behavior of volatiles and metasomatic fluids in mantle and crustal magmatic-hydrothermal systems remains a work in progress. Alkaline-carbonatite complexes usually originate from the mantle and typically host REE deposits which are thought to be almost always of a hydrothermal origin. The question thus arises as to the origin of the REE and fluids and if the alkaline and carbonatite magmas are accompanied by fluids from the mantle up and through the crust. This study presents the results of whole rock trace elements and Sm–Nd isotopes analyses of clinopyroxenites, melteigites, ijolites, melanosyenites, leucosyenites, granites, silicocarbonatites, magnesiocarbonatites, calciocarbonatites, ferrocarbonatites and polygenic breccias from the 1894 Ma Paleoproterozoic alkaline-carbonatite complex of Montviel, Abitibi, Canada. The metasomatic rocks range in REE concentrations from 100 ppm to 3.54 wt.% and show εNd values ranging from + 6.8 to − 7.2. Based on these results it is demonstrated that volatile-saturated magmas at Montviel were injected through 4 distinct mantle pulses which evolved by fractional crystallization, mixing of depleted mantle and crustal fluids and metasomatism.

Metasomatism

Carbonatite

Fractional crystallization (geology)

Trace element

Petrogenesis

Incompatible element

10.1016/j.oregeorev.2015.09.021

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Citations (9)

U-Pb Dating, Hydrogen and Chlorine Isotopic Systematics of the Whitlockite and Apatite from the Ungrouped Achondrite Northwest Africa 11119

82nd Annual Meeting of The Meteoritical Society (2019)

Sen Hu M. Anand I. A. Franchi X. Zhao Q. H. S. Chan

Achondrite

Whitlockite

Absolute dating

Source

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Citations (0)

U and Pb Isotopes in Allende Inclusions and Meteoritic Whitlockite

LPICo (1980)

J. H. Chen G. J. Wasserburg

We measured the isotopic composition of U and Pb in five Ca-Al rich inclusions from the Allende and in phosphates from the St. Severin chondrite and the Angra dos Reis achondrite. The purpose of this study is to test claims of large isotopic anomalies in U from meteoritic materials made by other workers.

Allende meteorite

Achondrite

Whitlockite

Carbonaceous chondrite

Source

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Citations (1)

Rare-gas chronology of calcium-rich achondrites

Journal of Geophysical Research Atmospheres (1966)

G. H. Megrue

Achondrite

Pyroxene