Rutile in Amphibolite Facies Metamorphic Rocks: A Rare Example from the East Qinling Orogen, China

Changming Wang,Hongyu Duan,Qi Chen,Shicheng Rao,Kangxing Shi,Leon Bagas,Lijun Liu,Jiaxuan Zhu

doi:10.3390/app11188756

Changming Wang, Hongyu Duan + Show 6 more

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https://doi.org/10.3390/app11188756

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Abstract

Rutile is an important ore mineral to meet the increasing demand of critical metal Ti in various sectors. Here we report a rare example of rutile deposits hosted within the Baishugang–Wujianfang amphibolite-facies metamorphic rocks in the East Qinling Orogen, central China. The rutiles are mostly located within or along the margins of biotite and show 94.6 to 99 wt% TiO2. Rutiles occur as chains, thin layers along the foliation, and dense clusters. The grains are coexisted with magnetite. Based on Zr-in-rutile thermometer the estimated crystallisation temperature is at 630 °C at 7.0 kba. Based on Cr/Nb ratio, the source of the rutile is correlated with Ti-bearing silicate minerals such as biotite from aluminous sedimentary protoliths. The rutile deposit formed during lower amphibolite-facies metamorphism, and is distinct from the eclogite- and granulite-related types elsewhere in the orogen. The LA-ICP-MS U–Pb analyses of rutiles from the deposit yield lower intercept 238U/206Pb ages of 386 ± 16 Ma at the Baishugang–Wujianfang district. These ages correspond to a Devonian arc–continent collisional event between the South and North Qinling domains in the East Qinling Orogen.

Highlights

IntroductionMetamorphic rutile deposits are an important source for Ti, a critical metal supporting the world’s increasing demand for various commodities [1,2]
We investigate a rare example of rutile deposits hosted within upper greenschist- to lower amphibolite-facies metamorphic rocks in the Baishugang–Wujianfang deposits of East Qinling Orogen (EQO) in central China [9]
Rutile deposits are hosted in amphibolite-facies metamorphic rocks in the East Qinling

Summary

Introduction

Metamorphic rutile deposits are an important source for Ti, a critical metal supporting the world’s increasing demand for various commodities [1,2]. Previous studies have shown that the source rocks for metamorphic and placer rutile deposits are those which have undergone high-pressure and high-temperature metamorphism such as eclogite, retrograde eclogite, and garnet amphibolite [3,4,5]. Greenschist- to amphibolitefacies metamorphism plays a major role in Ti enrichment at relatively low pressures and temperatures, the relationship between these lower metamorphic grades and formation of rutile is poorly investigated [6,7,8]. We investigate a rare example of rutile deposits hosted within upper greenschist- to lower amphibolite-facies metamorphic rocks in the Baishugang–Wujianfang deposits of East Qinling Orogen (EQO) in central China [9]

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Discussion

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