An AEM study of garnet clinopyroxenite from the Sulu ultrahigh-pressure terrane: formation mechanisms of oriented ilmenite, spinel, magnetite, amphibole and garnet inclusions in clinopyroxene

Hwang, Shyh‐Lung; Yui, Tzen‐Fu; Chu, Hao‐Tsu; Shen, Pouyan; Zhang, Ru‐Yuan; Liou, J. G.

doi:10.1007/s00410-010-0571-6

Cited by 11 publications

(8 citation statements)

References 57 publications

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“…Putnis, ), and has been realized in several inclusion‐host systems, in which the exsolved phase possesses a specific habit and follows a single COR, e.g. rutile needle in sagentic biotite (Shau et al ., ), rutile needle in corundum (Sahama, ), ilmenite rod in olivine (Dobrzhinetskaya et al ., ; Risold et al ., ), hematite rod/magnetite plate in olivine (Hwang et al ., ), ilmenite plate/spinel plate in clinopyroxene (Hwang et al ., ) as well as orthopyroxene blade in majoritic garnet (Sautter et al ., ; Spengler, ; Zhang et al ., ; Hwang et al ., ). In some cases where an exsolved phase has multiple orientation variants, e.g.…”

Section: Discussionmentioning

confidence: 99%

Origin of rutile needles in star garnet and implications for interpretation of inclusion textures in ultrahigh‐pressure metamorphic rocks

Hwang

Shen

Chu

et al. 2015

Journal Metamorphic Geology

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The asterism effect of star garnet has been attributed to the oriented distribution of needle-like rutile inclusions. Rutile needles occur in garnet from a wide range of metamorphic settings and rock bulk compositions, and their origin has been ascribed to different mechanisms, such as exsolution, and used to interpret petrological and tectonic processes. Results from an optical and transmission electron microscopy of Idaho star garnet indicate a co-precipitation origin. It was found that rutile needles are predominantly oriented along the <103> rt //<111> grt and <001> rt //<001> grt directions following multiple crystallographic orientation relationships (CORs); i.e. COR-1, 2, 2 0 , 3, 4 and 5 in 6-ray star garnet, and are oriented solely along the <103> rt //<111> grt directions following exclusively COR-2 in 4-ray star garnet. The sole presence of COR-2 <111> grt needles in the common 4-ray star garnet, in contrast to the presence of both <111> grt and <001> grt needles with multiple CORs in the rare 6-ray star garnet, suggests that the COR-2 <111> grt needle probably is the energetically most favoured variant, as is also supported by the coincidence site lattice considerations. The unique crystallography-controlled microstructures of 4-ray star garnet, including the cloudy domains behind the {111} grt or {100} grt fronts with abundant inclusions of rutile needle, rutile compound needle and multiple-phase-inclusion, as well as the clear domains behind the {110} grt fronts with only a few above inclusions concentrated exclusively within the linear, <110> grt -oriented, continuous tube-like domains, further suggest that the COR-2 <111> grt needles in 4-ray star garnet most likely have a growth-in origin, co-precipitating with garnet at its growth fronts close to thermodynamic equilibrium conditions. The 6-ray star garnet, on the other hand, most likely formed under far-from equilibrium conditions, thereby yielding a maximum of 99 crystallographic variants of rutile needles with multiple CORs in a single crystal. In the light of these findings, along with the common occurrences of the sole COR in many inclusion-host systems owing to the requirement to minimize the energy barrier in an exsolution process, the presence of both <103> rt //<111> grt and <001> rt //<001> grt needles with multiple CORs in garnet of Sulu eclogite and Erzegebirge quartzofeldspathic rock would therefore cast doubt on the assertion of an exsolution origin of rutile needles in garnet from these ultrahigh-pressure rocks.

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Section: Discussionmentioning

confidence: 99%

Origin of rutile needles in star garnet and implications for interpretation of inclusion textures in ultrahigh‐pressure metamorphic rocks

Hwang

Shen

Chu

et al. 2015

Journal Metamorphic Geology

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“…However, there is a lack of agreement about criteria to distinguish between host-inclusion CORs of different origins. Combined with other observations, different specific CORs have been considered evidence both for (Hwang et al 2011;Zhang et al 2011) and against (Hwang et al 2011(Hwang et al , 2013(Hwang et al , 2015 exsolution origins, and other authors have argued absence of a specific COR does not rule out inclusion formation by exsolution (Brearley and Champness 1986;Ague and Eckert Jr. 2012;Proyer et al 2013;Xu et al 2015).…”

Section: Introductionmentioning

confidence: 97%

“…All studies cited in this introduction consider the phases present, their compositions, distributions, shapes and any shapepreferred orientations. Some studies also include inclusion-based microstructures (Burton 1986;Perchuk 2008;Hwang et al 2011Hwang et al , 2013Hwang et al , 2015, compositional zoning or diffusion profiles in inclusions or hosts (Burton 1986;Ague and Eckert Jr. 2012;Hwang et al 2013;Khisina et al 2013), and crystallographic orientation relationships (CORs) between inclusion and host crystallographic directions (Brearley and Champness 1986;Hwang et al 2007Hwang et al , 2011Hwang et al , 2013Hwang et al , 2015Zhang et al 2011;Proyer et al 2013, Xu et al 2015.…”

Section: Introductionmentioning

confidence: 99%

Crystallographic orientation relationships in host–inclusion systems: New insights from large EBSD data sets

Griffiths

Habler

Abart

2016

American Mineralogist

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“…Crystallographic orientation relationships (CORs) in crystalline inclusion-host systems have often been used to derive inferences about the origin of the inclusions and the relative timing of growth of inclusions and their hosts (e.g., Hwang et al 2007Hwang et al , 2011Hwang et al , 2015Zhang et al 2011;Nestola et al 2014Nestola et al , 2017Nimis et al 2018). A frequent underlying assumption is that a COR that differs from random reflects minimization of interfacial energies and indicates a control by the host's crystal lattice during the formation of the inclusion.…”

Section: Introductionmentioning

confidence: 99%

Crystallographic orientations of magnesiochromite inclusions in diamonds: what do they tell us?

Nimis

Angel

Alvaro

et al. 2019

Contrib Mineral Petrol

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We have studied by X-ray diffractometry the crystallographic orientation relationships (CORs) between magnesiochromite (mchr) inclusions and their diamond hosts in gem-quality stones from the mines Udachnaya (Siberian Russia), Damtshaa (Botswana) and Panda (Canada); in total 36 inclusions in 23 diamonds. In nearly half of the cases (n = 17), [111]mchr is parallel within error to [111]diamond, but the angular misorientation for other crystallographic directions is generally significant. This relationship can be described as a case of rotational statistical COR, in which inclusion and host share a single axis (1 degree of freedom). The remaining mchr-diamond pairs (n = 19) have a random COR (2 degrees of freedom). The presence of a rotational statistical COR indicates that the inclusions have physically interacted with the diamond before their final incorporation. Of all possible physical processes that may have influenced mchr orientation, those driven by surface interactions are not considered likely because of the presence of fluid films around the inclusions. Mechanical interaction between euhedral crystals in a fluid-rich environment is therefore proposed as the most likely mechanism to produce the observed rotational COR. In this scenario, neither a rotational nor a random COR can provide information on the relative timing of growth of mchr and diamond. Some multiple, iso-oriented inclusions within single diamonds, however, indicate that mchr was partially dissolved during diamond growth, suggesting a protogenetic origin of these inclusions.

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An AEM study of garnet clinopyroxenite from the Sulu ultrahigh-pressure terrane: formation mechanisms of oriented ilmenite, spinel, magnetite, amphibole and garnet inclusions in clinopyroxene

Cited by 11 publications

References 57 publications

Origin of rutile needles in star garnet and implications for interpretation of inclusion textures in ultrahigh‐pressure metamorphic rocks

Origin of rutile needles in star garnet and implications for interpretation of inclusion textures in ultrahigh‐pressure metamorphic rocks

Crystallographic orientation relationships in host–inclusion systems: New insights from large EBSD data sets

Crystallographic orientations of magnesiochromite inclusions in diamonds: what do they tell us?

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