Fig 7 - uploaded by Ikuo Katayama
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Garnet compositions of inclusion and matrix plotted on ternary diagram of (Almandine + Spessartine)–Grossular–Pyrope. ( a ) Coesite- bearing eclogite; ( b ) diamond-bearing biotite gneiss.
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Zircon is an excellent material to preserve the complex history of ultrahigh-pressure (UHP) metamorphic rocks, whereas mineralogical evidence of UHP conditions is mostly obliterated in matrix assemblages as a result of extensive retrograde overprinting during exhumation. Zircons from the Kokchetav UHP-HP massif contain numerous inclusions of graphi...
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... inclusions in zircon from the coesite-bearing eclogite are rare compared with omphacite inclusions. The chemical compo- sition of garnets from both inclusions and matrix is plotted on the (Alm + Sps)-Prp-Grs ternary diagram (Fig. 7). Matrix garnets have almost homogeneous composition, slightly zoned with decreasing pyrope content from core to rim. On the other hand, garnet inclusions show a wide compositional variation: four crystals are Alm-rich (47-53%) and contain considerable spessartine (0.9-1.2%) component whereas the other grains are consistent with matrix ...
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Large garnet crystals (porphyroblasts) occur in migmatized biotite paragneiss near Senorady (Moldanubian Zone, Western Moravia). In their chemical composition prevails almandine component (Alm68–72 Sps3–10 Prp16–22 Grs0–6 Adr1–6). Only weak diffuse zonation (Mn-rich core and Mg-rich rim) and inclusions of quartz, ilmenite, apatite and rutile is not...
Citations
... The inclusions in zircon have been studied more intensively in the last few decades but mostly from metamorphic rocks, where it served as a capsule for reconstructing metamorphic history (e.g. Liu et al., 2001;Rubatto and Hermann, 2007;Katayama and Maruyama, 2009;Liu and Liou, 2011;Perraki and Faryad, 2014;Zhang et al., 2017;Gonzalez et al., 2021;Fei and Liu, 2022), and less frequently in igneous petrology (e.g. Jennings et al., 2011;Gudelius et al., 2020;Zeng et al., 2020). ...
Micro-Raman spectroscopy was used to determine the inclusions in magmatic zircon from the Late Cretaceous A-type acid igneous rocks in the Slavonian mountains (Mt. Papuk and Mt. Požeška Gora), in the southwestern part of the Pannonian Basin (Croatia). The mineral inclusions detected in the early-crystallised zircon are anatase, apatite, hematite, ilmenite and possibly magnetite. Numerous melt inclusions comprise albite, cristobalite, hematite, kaolinite, K-feldspar, kokchetavite, kumdykolite muscovite and quartz, where this mineral association is characteristic of so-called nanorocks (nanogranites), commonly found in peritectic garnets from high-grade metamorphic rocks. Here we present the first finding of kokchetavite and kumdykolite in a magmatic zircon. Together with anatase and hematite, these polymorphs are likely evidence of rapid uplift and consequent rapid cooling of hot oxidised magma generated in the lower crust and its emplacement in the upper crustal level. This finding provides further confirmation that kumdykolite and kokchetavite do not require ultra-high pressure (UHP) to form and should not be considered exclusively UHP phases. The rapid uplift was possible due to the formation of accompanying extensional deep rifts during the tectonic transition from compression to extension, associated with the closure of the Neotethys Ocean in the area of present-day Slavonian mountains in the Late Cretaceous (∼82 Ma).
... Despite the fact that the ultra-high-pressure metamorphic complex of the Kokchetav subduction-collision zone has been extensively studied, many questions regarding the nature of the protoliths of diamondiferous rocks and the interpretation of zircon age data remain unanswered (Claoué-Long et al., 1991;Shatsky et al., 1999Shatsky et al., , 2006aShatsky et al., , b, 2015Shatsky et al., , 2021Hermann et al., 2001;Katayama et al., 2001;Katayama and Maruyama, 2009;Ragozin et al., 2009;Stepanov et al., 2016;Rezvukhina et al., 2020). The most unusual diamondiferous metamorphic rocks of the Kumdy-Kol microdiamond deposit are garnet-pyroxene rocks occurring as boudines and interlayers in garnet-biotite gneisses and granite gneisses. ...
... In (Katayama and Maruyama, 2009), the U-Pb age was determined and the inclusions in zircon from various types of diamondiferous and non-diamondiferous metamorphic rocks of the Kokchetav subduction-collision zone of the massif were studied. Based on these data, Р-Т-t trends in the metamorphism of high-and ultra-high-pressure rocks were determined. ...
... It is noteworthy that, among the diamondiferous rocks of the Kumdy-Kol deposit, only zircon from garnet-biotite gneisses was previously dated (Claoué-Long et al., 1991;Katayama et al., 2001;Katayama and Maruyama, 2009). Thus, no one has been able to obtain U-Pb ages and study the inclusions in zircon from garnet-pyroxene, garnet-pyroxene-quartz, and calc-silicate diamondiferous rocks, whose protoliths cause a lot of controversy. ...
This paper describes the results of studying inclusions and determining the U–Pb age in zircon from the diamondiferous garnet–pyroxene rock of the Kumdy-Kol metamorphogenic diamond deposit, located in the Kokchetav subduction-collision zone. The distribution of rare earth elements in garnet and clinopyroxene is used as a basis for estimating the equilibrium pressure (5.5 ± 0.3 GPa) and temperature (993 ± 24 °C), which correspond to the diamond stability field. The composition of mineral inclusions in zircon indicates its formation at both the progressive and the regressive stage of metamorphism. The concordia diagram shows that the figurative points of zircon lie on a discordia with an upper intersection at 1953 ± 139 Ma and a lower intersection at 512 ± 4 Ma. The main peak on the graph of the probability density distribution of zircon ages corresponds to an age of 519 Ma. The presence of grossular–almandine garnet inclusions in zircon confirms the previous assumption that the basement rocks of the Kokchetav massif act as protoliths of garnet–pyroxene rocks.
... As a ubiquitous and accessory mineral in metamorphic rocks, zircon plays a fundamental role in tracing crustal evolution during continental orogeny (Hermann and Rubatto, 2014;Katayama and Maruyama, 2009;Rubatto and Hermann, 2007). Zircon in UHP rocks commonly contains index mineral inclusions, the compositions of which can survive from later-stage metamorphic or magmatic overprinting . ...
... (3) oriented rutile inclusions in garnet and clinopyroxene as well as oriented and complex clinopyroxene-orthopyroxene features, interpreted as exsolution subsequent to ultrahighpressure metamorphism; and (4) oriented quartz inclusions in fayalitic olivine, interpreted as exsolution from an ahrensite (Fe 2 SiO 4 ) precursor (Glassley et al., 2014(Glassley et al., , 2016. If correct, these rocks not only represent Earth's oldest supracrustal ultrahigh-pressure rocks but also show the lowest metamorphic gradients and highest-pressure conditions in the entire dataset of metamorphic rocks through time, together with rocks of the Phanerozoic Kokchetav massif (Katayama and Maruyama, 2009;Fig. 1). ...
Modern-style plate tectonics is characterised by the
global operation of cold and deep subduction involving blueschist facies and
ultrahigh-pressure metamorphism. This has been a common process since the
Neoproterozoic, but a couple of studies indicate similar processes were
active in the Paleoproterozoic, at least on the local scale. Particularly
conspicuous are extreme ultrahigh-pressure conditions of ∼ 7 GPa at thermal gradients < 150 ∘C GPa−1 proposed for
metamorphic rocks of the Nordre Strømfjord shear zone in the western part
of the Paleoproterozoic Nagssugtoqidian Orogen of Greenland. By acquiring a
large dataset of heavy minerals (n = 52 130) and garnet major-element
composition integrated with mineral inclusion analysis (n=2669) from
modern sands representing fresh and naturally mixed erosional material from
the metamorphic rocks, we here intensely screened the area for potential
occurrences of ultrahigh-pressure rocks and put constraints on the
metamorphic evolution. Apart from the absence of any indications pointing to
ultrahigh-pressure and low-temperature–high-pressure metamorphism, the
results are well in accordance with a common Paleoproterozoic
subduction–collision metamorphic evolution along a Barrovian-type
intermediate temperature and pressure gradient with a pressure peak at the
amphibolite–granulite–eclogite-facies transition and a temperature peak
at medium- to high-pressure granulite-facies conditions. In addition, we
discuss that all “evidence” for ultrahigh-pressure metamorphism proposed
in the literature for rocks of this area is equivocal. Accordingly, the
Nordre Strømfjord shear zone is not an example of modern-style plate
tectonics in the Paleoproterozoic or of very low thermal gradients and
extreme pressure conditions in general.
... This interpretation can be supported by the characters of zircons and modeling results. For example, the REE features of the metamorphic zircons in Yaganbuyang garnet amphibolites that show flat HREE and virtually no negative Eu anomalies, are consistent with the characters of zircons in eclogites Zheng et al., 2013;Liu L et al., 2012;Rubatto et al., 2011;Katayama and Maruyama, 2009;Liu F L et al., 2006;Rubatto and Hermann, 2003;Rubatto, 2002;Sun et al., 2002), which indicates that these metamorphic zircons in garnet amphibolites were formed at eclogite facies. The modeling results in Fig. 9b also suggest that the peak stage appears to be stable at eclogite facies. ...
Garnet amphibolite is one of the common metabasic rocks exposed in collisional orogenic belt, the metamorphic evolution of which is associated closely with orogenic processes. The Yaganbuyang garnet amphibolites occur as blocks hosted by massive granitic gneiss, and consist mainly of hornblende, garnet, clinopyroxene, plagioclase, biotite, quartz with minor rutile/ilmenite and phengitic muscovite. These garnet amphibolites were interpreted to have experienced decompression-dominated evolution that can be divided into three generations (M1, M2, M3), based on the petrographic observations and phase equilibria modeling calculated by THERMOCALC. The assemblage of the first generation (M1) is inferred to possibly be dominated by garnet + omphacite + rutile + phengite + quartz, which is modeled to be roughly stable at P > 25 kbar and T > 800 °C. The second generation (M2) is characterized by the local symplectites of clinopyroxene + plagioclase produced from omphacite, indicating a near-isothermal decompression from ∼23.8 kbar/875 °C to ∼10 kbar/852 °C. The third generation (M3) is marked by the kelyphitic rims of plagioclase + hornblende around garnet and of hornblende + ilmenite around clinopyroxene, involving the late-stage retrogression from ∼9.8 kbar/848 °C to ∼5.8 kbar/645 °C. Zircon U-Pb dating yielded one group metamorphic age of c. 500 Ma that is interpreted to represent the timing of the peak eclogite-facies metamorphism. A combination of petrography observation, phase modeling results and geochronology data suggests that the Yaganbuyang garnet amphibolites have once undergone eclogite-facies metamorphism by continental subduction rather than crustal thickening. Therefore, the Yaganbuyang area is an eastward extension part of the South Altyn HP-UHP metamorphic belt.
... (2) The P-T conditions during peak metamorphism were modeled to have been ~ 36.2 kbar/920 • C, based on the phase equilibria modeling. (3) The flat HREE patterns and lack of negative Eu anomalies for the metamorphic zircons in Kuruksayi mafic granulites show that these zircons were formed at eclogite-facies conditions (Rubatto, 2002;Sun et al., 2002;Rubatto and Hermann, 2003;Liu et al., 2006;Katayama and Maruyama, 2009;Rubatto et al., 2011;Liu et al., 2012;Zheng et al., 2013;Wang et al., 2016). Accordingly, the Kuruksayi area may record an episode of deep subduction similar to that recorded in the adjacent areas of the Jianggalesayi and Danshuiquan to the west and Yinggelisayi to the east. ...
The South Altyn high-pressure–ultrahigh-pressure (HP–UHP) metamorphic belt in West China records the processes of deep continental subduction (>150–300 km). The HP mafic granulite pods hosted by massive granitic gneiss were for the first time discovered in the Kuruksayi area of the South Altyn Orogen, and they consist mainly of garnet, clinopyroxene, plagioclase, hornblende, biotite, and quartz, with minor rutile, ilmenite, and K-feldspar. The garnets vary in grain size and chemical zoning, and can be divided into three types: subhedral porphyroblastic (g1), anhedral porphyroblastic (g2), and neoblastic fine (g3) grains. Four generations of mineral assemblage (M1–M4) are recognized, and are used to constrain the P–T evolution of the mafic granulites using phase equilibria modeling calculated by THERMOCALC. The first generation (M1) is represented by the core domains of g1 (g1C) that have inclusions of rutile and quartz and conspicuous chemical zoning. A pre-peak prograde stage of metamorphism from ∼15.8 kbar/600 °C to ∼19.2 kbar/655 °C is recorded by g1C. The second generation (M2) is inferred to consist of garnet + omphacite + phengite + rutile + quartz and is recorded in the mantle domains of g1 (g1M). Modeling suggests that this is representative of conditions that reached a maximum P–T of ∼36.2 kbar/920 °C. The third generation (M3) is characterized by intergrowths of clinopyroxene + plagioclase and biotite + plagioclase, and this stage is recorded by the compositions of g2 with modeling suggesting an evolution from ∼17.8 kbar/820 °C to ∼11.5 kbar/826 °C, consistent with near-isothermal decompression. The last generation (M4) is characterized by kelyphitic rims of plagioclase + hornblende around garnet and the hornblende coronas that encompass symplectitic clinopyroxene, and is recorded by the compositions of g3. Modeling suggests evolution from ∼11.5 kbar/826 °C to ∼8.7 kbar/735 °C, compatible with near-isobaric cooling. These four stages of metamorphism together establish a clockwise P–T path, which indicates a series of tectonic processes that took the continental slab from subduction to exhumation. Zircon U–Pb dating by LA–ICP–MS yielded two distinct clusters of ages: c. 897 Ma magmatic protolith ages and c. 494 Ma metamorphic ages. The metamorphic ages are interpreted to represent the timing of the eclogite-facies metamorphism, and are similar to the metamorphic ages of other HP/UHP rocks elsewhere in the South Altyn Orogen. Accordingly, we propose that the Kuruksayi mafic granulites underwent UHP metamorphism similar to that recorded in other South Altyn eclogites exposed in Jianggalesayi and Danshuiquan to the west and Yinggelisayi to the east.
... A distinctive feature of the Kokchetav massif is a high mean rate (1.8 cm/year) of rock exhumation (Hacker et al., 2003;Dobretsov et al., 2006), which, in particular, has been considered as a reason for coesite preservation during the exhumation (Mosenfelder et al., 2005). The age of the peak metamorphism for the Kokchetav UHPM rocks estimated by U-Pb zircon dating (Claoué-Long et al., 1991;Hermann et al., 2001Hermann et al., , 2006Katayama et al., 2001Katayama et al., , 2003Katayama and Maruyama, 2009;Stepanov et al., 2016b) as well as by Sm-Nd mineral isochrons from the diamond-bearing rocks and associated rocks (Shatsky et al., 1999) is ca. 530 Ma. ...
Zircon crystals from diamondiferous kyanite gneisses of the Barchi-Kol area (Kokchetav massif, Northern Kazakhstan) have been investigated by a combined application of cathodoluminescence (CL), Raman spectroscopy and electron probe microanalysis (EPMA). The zircon crystals exhibit up to four distinct domains characterised by significantly different CL signatures and parameters of the ν 3 (SiO 4 ) (1008 cm –1 ) Raman band (i.e. full width at half maximum, position and intensity). Extremely metamict zircon cores (Domain I) host inclusions of low-pressure minerals (quartz and graphite) and the outer mantles (Domain III) are populated by ultrahigh-pressure relicts (diamond and coesite), whereas inner mantles (Domain II) and overgrowth rim zones (Domain IV) are inclusion free. Both the zircon cores and rims have very low Ti concentrations, implying formation temperatures below 760°C. The Ti content in the inner mantles (up to 40 ppm) is indicative of temperatures in the 760–880°C range. The temperature estimates for the outer mantles are 900–940°C, indicating a pronounced overlap with the peak metamorphic values yielded by the Zr-in-rutile geothermometer for the same rocks (910–950°C). The internal textures of the zircons and the occurrence of index minerals within the distinct domains allow us to unravel the stages of the complex metamorphic history recorded in the zircon. Our data show that the zircon cores are inherited seeds of pre-metamorphic (magmatic?) origin, the inner mantles were formed on the prograde metamorphic stage, the outer mantles record ultrahigh-pressure metamorphism and the outermost rims mark the retrograde metamorphic stage. The observed zircon internal textures are thus clearly correlated with distinct growth events, and in some examples reflect a major part of the metamorphic history. It is concluded that the combined application of the CL, Raman spectroscopy and EPMA techniques to zircon offers significant potential for deciphering the metamorphic evolution of deeply-subducted rocks.
... Zircon is one of the most common accessory minerals in various igneous, sedimentary, and metamorphic rocks. Furthermore, due to its large stability field and its physical robustness, zircon often hosts ultrahigh pressure (UHP) metamorphic minerals such as coesite and diamond (Parkinson and Katayama 1999;Ye et al. 2000b;Hermann et al. 2001;Rubatto and Hermann 2007;Katayama and Maruyama 2009). Zircon can be used for a wide range of applications, including U-Pb geochronology, and potential use as a host phase for the disposal of excess weapons-grade Pu because of its capacity to incorporate radioactive elements, (e.g., Ewing et al. 1995). ...
The structural and chemical properties of zircon inclusions in garnet megablasts from the Dora Maira Massif (Western Alps, Italy) were characterized in detail using charge contrast imaging, Raman spectroscopy, and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The aim of this work is to determine to what extent the degree of metamictization, metamorphic recrystallization, inherent structural heterogeneity, chemical composition, and zoning, along with the elastic stress imposed by the host mineral, can influence the Raman peak position of the zircon inclusion and hence, the residual pressure estimated via Raman geo-thermobarometry. We show and confirm that metamictization and inherent structural heterogeneity have a major influence in the Raman spectra of zircon in terms of peak position and peak width. We suggest that, for spectral resolution of 2 cm−1, the peak width of the B1g mode near 1008 cm−1 of reliable grains must be smaller than 5 cm−1. The method can be applied to both inherited igneous and newly formed Alpine metamorphic crystals. By coupling structural and chemical information, we demonstrate that there are no significant differences between the Raman spectra of zircon with oscillatory-zoned texture, formed during magmatic crystallization, and those formed by fluid-induced Alpine (re)crystallization. The discrimination between magmatic and metamorphic zircon based only on micro-textural constraints is not robust. Finally, our results allow establishing a protocol devoted to the selection of reliable buried zircon inclusions, relying only on Raman spectroscopic measurements, to use for elastic thermobarometry applications.
... UHP metamorphic mineral assemblages are often replaced during retrograde metamorphism due to hydration and re-equilibration during exhumation (Katayama and Maruyama, 2009). As a result, mineralogical evidence of UHP metamorphism has largely been restricted to armoured inclusions found in refractory minerals such as garnet and zircon (Parkinson and Katayama, 1999;Katayama and Maruyama, 2009). ...
... UHP metamorphic mineral assemblages are often replaced during retrograde metamorphism due to hydration and re-equilibration during exhumation (Katayama and Maruyama, 2009). As a result, mineralogical evidence of UHP metamorphism has largely been restricted to armoured inclusions found in refractory minerals such as garnet and zircon (Parkinson and Katayama, 1999;Katayama and Maruyama, 2009). In this contribution it is shown that rutile from the UHP rocks of the Dora-Maira massif is also capable of retaining UHP inclusions such as coesite, pyrope and high-Siphengite. ...
... In the present study a number of coesite inclusions within rutile (Fig. 3), confirmed using Raman spectroscopy, show no visible fractures or transformation to quartz. The fact that these inclusions are untransformed and monomineralic implies that there was very little or no aqueous fluid present within the enclosing rutile (Parkinson and Katayama, 1999;Katayama and Maruyama, 2009), or that rutile had simply protected its interior from external fluids. The main Raman peak for bimineralic coesite inclusions in garnet occurs at 521 cm −1 (Boyer et al., 1985), however in this study the main peak obtained for monomineralic coesite inclusions occurs at 523 cm −1 (Fig. 3) which is comparable to peaks obtained for similar inclusions in zircon from the Kokchetav massif (Parkinson and Katayama, 1999). ...
Metamorphic garnet commonly contains needle‐like rutile inclusions as well as equant rutile inclusions that surround quartz inclusions and range in size from submicrometer to nanometer. Although the origin of these equant rutile inclusions, i.e. exsolution or non‐exsolution, has important implications for petrological and tectonic processes, the crystallographic characteristics of these inclusions have rarely been studied because of the small sizes and analytical difficulties involved. Here we report the crystallographic characteristics pertinent to the genetic origin of minute equant rutile inclusions in cloudy, nearly spherically‐shaped garnet domains with Ti‐depleted compositions surrounding quartz inclusions in UHP garnet from several diamondiferous Erzgebirge quartzofeldspathic gneissic rock samples. TEM analyses show that the equant rutile crystals in cloudy garnet domains are partially bounded by the low‐energy {100}rt ± {110}rt ± {101}rt facets and have rather random crystallographic orientation relationships (CORs) with the garnet host, with preferential alignment of low‐energy lattice planes, e.g. {100}rt//{112}grt, for some rutile crystals. Whereas the rather random CORs are unlikely to be attributed to solid‐state exsolution subjected to the stringent topotactic garnet lattice constraints, the characteristic subhedral {100}rt ± {110}rt ± {101}rt crystal forms of rutile can be rationalized by a metasomatic dissolution‐reprecipitation mechanism via a fluid phase. In this scenario, the quartz + fluid inclusions in garnet were first subjected to decompression microcracking during rock exhumation, followed by dissolution of Ti‐bearing garnet matrix at the crack tips or along the crack surfaces and subsequent reprecipitation of rutile, apatite, gahnite, akdalaite, and Ti‐depleted garnet. The rapid coalescence between rutile and garnet crystals in fluid or direct attachment of rutile crystals onto the dissolving crack surfaces would then yield the rather random CORs as reported here. These results, along with previous work on rutile needles, indicate rather diverse genesis of rutile inclusions in various crystal forms, thus shedding light on the controversial exsolution origin for other inclusion suite/microstructure in minerals.
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... Inclusions in zircon have showed to be a valuable tool in connecting P-T conditions to age information (Gilotti, 2013;Hermann et al., 2001;Katayama and Maruyama, 2009), especially in (U)HP rocks in which prograde to peak assemblages are easily replaced during decompression. Oscillatory cores contain numerous sub-μm inclusions of amphibole, clinopyroxene and quartz. ...
The identification of markers of subduction zones in orogenic belts requires the
estimation of paleo-geothermal gradients through pressure-temperature-time (P-T-t)
estimates in mafic rocks that potentially derive from former oceanic units once.
However, such markers are rare in supracrustal sequences specially in deeply eroded
and weathered Precambrian orogens, and reconstructing their metamorphic history is
challenging because they are commonly retrogressed and only preserve a few mineral
relicts of high-pressure metamorphism. Metamorphosed mafic rocks from Pouso
Alegre region of the Neoproterozoic Southern Brasília Orogen outcrop as rare lenses
within continental gneisses. They have previously been classified as retrograde
eclogites, based on the presence of garnet and the characteristic symplectitic texture
replacing omphacite. These rocks were interpreted to mark the suture zone between
the Paranapanema and São Francisco cratons. To test the possible record of eclogitic
conditions in the Pouso Alegre mafic rocks, samples including the surrounding felsic
rocks have been investigated using quantitative compositional mapping, forward
thermodynamic modeling and in-situ dating of accessory minerals to refine their P-T-t
history. In the metamorphosed mafic rocks, the peak pressure assemblage of garnet
and omphacite (Jd20, reconstructed composition) formed at 690 ± 35 °C and 13.5 ± 3.0
kbar, whereas local retrogression into symplectite or corona occurred at 595 ± 25 °C
and 4.8 ± 1.5 kbar. The two reactions were coupled and thus took place at the same
time. A zircon U-Pb age of 603 ± 7 Ma was obtained for metamorphic rims and linked
to the retrogression stage. Monazite and metamorphic zircon U-Th-Pb ages for the
surrounding rocks are at ca. 630 Ma and linked to peak pressure conditions similar to
the one recorded by the mafic rocks. The low maximal pressure of 14 kbar and the high
geothermal gradient do not necessarily support subduction process-related
metamorphism but, more likely, metamorphism related to continental collision.
