Next Article in Journal
Petrogenesis of Ore-Hosting Diorite in the Zaorendao Gold Deposit at the Tongren-Xiahe-Hezuo Polymetallic District, West Qinling, China
Previous Article in Journal
Green Preparation of Nanoporous Pyrrhotite by Thermal Treatment of Pyrite as an Effective Hg(Ⅱ) Adsorbent: Performance and Mechanism
Article Menu

Export Article

Open AccessArticle
Minerals 2019, 9(2), 75; https://doi.org/10.3390/min9020075

Olivine–Spinel Diffusivity Patterns in Chromitites and Dunites from the Finero Phlogopite-Peridotite (Ivrea-Verbano Zone, Southern Alps): Implications for the Thermal History of the Massif

1
Department of Earth Sciences, Università degli Studi di Milano, via Botticelli 23, 20133 Milan, Italy
2
Department of Geology and Geoenvironment, National and Kapodistrian University of Athens (Zografou Campus), 15784 Athens, Greece
3
Ecoresources PC, Avdela str. 5, Kalamaria, 55131 Thessaloniki, Greece
*
Author to whom correspondence should be addressed.
Received: 20 December 2018 / Revised: 22 January 2019 / Accepted: 24 January 2019 / Published: 27 January 2019
(This article belongs to the Special Issue Mineral Deposits Related to Mantle Rocks)
Full-Text   |   PDF [3902 KB, uploaded 27 January 2019]   |  

Abstract

The study of Mg–Fe2+ subsolidus exchange between olivine and spinel is a powerful tool to unravel the thermal history of ultramafic rocks. We have implemented such a study using olivine–spinel diffusivity patterns in fresh mineralogical samples from the Finero mafic-ultramafic Complex in the Ivrea-Verbano zone of Northern Italy. Our analytical suite includes chromitites and dunites of the Phlogopite-Peridotite Unit from the core of the Complex. Primary and re-equilibrated olivine and spinel compositions were derived from diffusivity curves calculated by fitting data via an exponential function. Resulting XMg (Mg/(Mg + Fe2+) values were then used for geothermometry. Samples are found to demonstrate a maximum temperature of 849 °C and a minimum temperature of 656 °C; these temperatures coincide with the limits of elemental exchange in this mineralogic system. We were unable to identify primary olivine/spinel compositions related to the original formation of the dunite–chromitite suite during Early Permian metasomatic activity. Temperature of 849 °C is ascribed to the Late Triassic re-heating event dated at 208 ± 2 Ma. Continuous cooling followed this event at rates of 10−4 and 10−2 °C/yr until cessation of elemental exchange activity at ~656 °C. A rapid cooling rate is associated with the uplift and subsequent decrease of geothermal gradient during the early stages of the opening of the Piemont ocean basin. View Full-Text
Keywords: Finero complex; chromitite; olivine–spinel equilibrium; geothermometry; diffusivity patterns; cooling rates Finero complex; chromitite; olivine–spinel equilibrium; geothermometry; diffusivity patterns; cooling rates
Figures

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

Supplementary material

SciFeed

Share & Cite This Article

MDPI and ACS Style

Bussolesi, M.; Grieco, G.; Tzamos, E. Olivine–Spinel Diffusivity Patterns in Chromitites and Dunites from the Finero Phlogopite-Peridotite (Ivrea-Verbano Zone, Southern Alps): Implications for the Thermal History of the Massif. Minerals 2019, 9, 75.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics

1

Comments

[Return to top]
Minerals EISSN 2075-163X Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top