Epidote-(Sr), CaSrAl2Fe3+(Si2O7)(SiO4)(OH), a new mineral from the Ananai mine, Kochi Prefecture, Japan

Minakawa, Tetsuo; Fukushima, Hiroyuki; Nishio–Hamane, Daisuke; Miura, Hiroyuki

doi:10.2465/jmps.071220

Cited by 13 publications

(8 citation statements)

References 9 publications

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“…Eu REE Fig. 23 Fujinaga et al, 2006bMinakawa et al 2008Sr Nakamura 1990 Type A Fujinaga et al, 2006b). REE data of PAAS and TAG (Trans-Atlantic Geotraverse hydrothermal field) hydrothermal fluids are from Taylor and McLenann (1985) and Mitra et al (1994), respectively.…”

Section: Cementioning

confidence: 99%

日本列島付加体中に胚胎する古海洋底で生成した鉱床

Nozaki

Fujinaga

Kato

2018

Jour. Geol. Soc. Japan

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Basement rocks of the Japanese islands consist mainly of accretionary complexes younger than ca. Ma. Various types of stratiform and/or massive ore deposits that formed on a paleo-seafloor are hosted within the Japanese accretionary complexes. In the present study, we review recent progress on metallogenetic research and outline unsolved problems related to these types of deposits, such as the Besshi-type sulfide deposits, bedded ferromanganese deposits, and bedded manganese deposits related/unrelated to greenstone. Besshitype deposits within the Sanbagawa Belt formed by vigorous hydrothermal activity at a pelagic mid-ocean ridge during the Late Jurassic, and sulfide ore was preserved by the concomitant Late Jurassic Ocean Anoxic Event. Besshi-type deposits, which are closely associated with in-situ greenstone in the Northern Shimanto Belt, formed by ridge subduction during the Late Cretaceous. Certain aspects of the genesis of other Besshi-type deposits in the mélange zone of the Northern Shimanto and Chichibu Belts remain unresolved, although the Tsuchikura deposit occurs as an olistolith. Bedded ferromanganese deposits, so-called umber deposits, are derived from hydrothermal sediments at the periphery of the mid-ocean ridge, whereas bedded manganese deposits closely associated with greenstones were originally produced as hydrothermal sediments around seamounts. Bedded manganese deposits that occur within pelagic chert sequences without greenstone are considered to be formed by drastic changes in the redox state of deep water due to the influx of oxic and silicapoor surface seawater into anoxic and high-manganese stagnant deep water. However, whether bedded manganese deposits without greenstone are hydrothermal or hydrogenous in origin remains controversial. Although the problems are complex, future multidisciplinary research should clarify many of the unsolved questions related to metallogenesis.

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Section: Cementioning

confidence: 99%

日本列島付加体中に胚胎する古海洋底で生成した鉱床

Nozaki

Fujinaga

Kato

2018

Jour. Geol. Soc. Japan

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“…Dörsam et al (2007) synthesized strontium-bearing clinozoisite in the compositional range Sr/(Ca + Sr) = 0.078 to 0.51; they showed that strontium partitions into the larger A2 site and that significant strontium incorporation at the A1 site occurs only for Sr/(Ca + Sr) >0.45. Minagawa et al (2008) reported that epidote-(Sr) also has a strong site preference for strontium in the A2 site with A2 (Sr/Ca) / A1 (Sr/Ca)~147. Thus, the assumption that strontium is fully ordered in the A2 sites is a reasonable simplification for discussing the epidote composition of the Kurosegawa samples, i.e.…”

Section: Bulk-rock Compositionsmentioning

confidence: 99%

“…Strontium-rich epidote has been reported from a variety of metamorphic rocks including metasediments of greenschist facies in New Zealand (Grapes and Watanabe, 1984); eclogite in the Bjørkedalen peridotite from the Western Gneiss Region, Norway (Brastad, 1985); metabasite in serpentinite from Guatemala (Harlow, 1994); ultrahigh-pressure (UHP) eclogites from the Su-Lu belt, China (Nagasaki and Enami, 1998); prehnite rock in the serpentinite mélange from the Itoigawa-Ohmi District, Japan (Miyajima et al, 2003); a carbonatite skarn from the Canary Islands, Spain (Ahijado et al, 2005); and the manganese-ore deposits in the Ananai mine, Kochi, Japan (Minagawa et al, 2008). Three types of models have been proposed for the formation of strontium-rich epidote.…”

Section: Formation Of Strontium-rich Epidotementioning

confidence: 99%

Retrograde strontium metasomatism in serpentinite mélange of the Kurosegawa Zone in central Kyushu, Japan

Miyazoe¹,

Enami²,

Nishiyama³

et al. 2012

Mineral. mag.

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Strontium-rich epidote, including epidote-(Sr) and epidote with major amounts of Sr (i.e. epidote containing up to 17.3 wt.% SrO), was found in pumpellyite schist and epidote blueschist in a tectonic block in the serpentinite mélange of the Kurosegawa Zone, central Kyushu, Japan. The tectonic block is 20 m wide and made primarily of lawsonite blueschist, with subordinate amounts of pumpellyite schist and epidote blueschist. The pumpellyite schist typically occurs at the edge of the block and is composed mainly of pumpellyite with subordinate amounts of strontium-poor epidote, albite and chlorite, and thin veins of fine-grained calcite and clinopyroxene. Epidote-(Sr) forms rims around strontium-poor epidote, fills fractures in strontium-poor epidote and also occurs interstitially between pumpellyite aggregates and along the boundaries between pumpellyite and calcite-clinopyroxene veins. The epidote blueschist is found between the pumpellyite schist and lawsonite blueschist, and consists mainly of sodic amphibole, epidote and titanite, with albite veining. Strontium-rich epidote occurs as rims, replacing Sr-poor epidote near the albite vein. The bulk strontium contents of the rocks are as follows: lawsonite blueschist (200 ppm), epidote blueschist (2800 ppm) and pumpellyite schist (~10,700 ppm). The chemical and petrological characteristics of the Sr-rich epidote-bearing metabasites suggest that the infiltration of a metamorphic fluid promoted extensive Sr metasomatism during the later stages of high-pressure metamorphism.

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“…and T is tetrahedral sites (Armbruster et al 2002;Mills et al, 2009). Epidote-group minerals of epidote-supergroup, such as clinozoisite, epidote and piemontite, are important Sr containers in metamorphic rocks (e.g., Grapes and Watanabe, 1984;Mottana, 1986;Reinecke, 1986;Nagasaki and Enami, 1998;Enami, 1999;Miyajima et al, 2003;Nagashima et al, 2006), metamorphosed manganese ore deposits (e.g., Kato and Matsubara, 1986;Bonazzi et al, 1990;Perseil, 1990;Minakawa, 1992;Nagashima et al, 2007;Minakawa et al, 2008; A d v a n c e P u b l i c a t i o n A r t i c l e al., 2010), and metamorphosed manganiferous iron ore deposits (Akasaka et al, 1988;Togari et al, 1988). Thus, the occurrence and crystal chemical properties of Sr-bearing epidote-group minerals, such as solubility of Sr and its effect on the Mn and Fe contents and crystal structure, have been interested in.…”

Section: Introductionmentioning

confidence: 99%

Crystal chemistry of Sr–rich piemontite from manganese ore deposit of the Tone mine, Nishisonogi Peninsula, Nagasaki, southwest Japan

Nagashima

Sano

Kochi

et al. 2020

Journal of Mineralogical and Petrological Sciences

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The crystal chemistry of Sr-rich piemontite from a layered manganese ore deposit of the Tone mine, Nishisonogi Peninsula, Japan, was studied using methods of electron microprobe analysis, single crystal X-ray structural refinement, 57 Fe Mössbauer spectroscopy, and X-ray and Time-of-Flight neutron Rietveld analyses to elucidate the intracrystalline distributions of Sr, Mn, and Fe and the general and individual features on the structural changes with Sr contents in piemontite and epidotes. Piemontite in the most piemontite-dominant layer of an ore is [Ca 1.73(15) Sr 0.22(13) ] Σ1.95 [Al 1.99(9) Mn 3+ 0.68(8) Fe 3+ 0.37(8) Mg 0.01(0) ] Σ3.05 Si 2.99(1) O 12 (OH) (Z = 2) in the average chemical formula. A single crystal X-ray structural refinement (R 1 = 2.51% for 2417 unique reflections) resulted in the unit-cell parameters of a = 8.8942(1), b = 5.6540(1), c = 10.1928(2) Å, and β = 115.100(1)°; and the occupancies of Ca 0.711(3) Sr 0.289 , Al 0.898(4) (Mn + Fe) 0.102 , and (Mn + Fe) 0.949(4) Al 0.051 at the X A2, VI M1, and VI M3 sites, respectively. All Fe in a powdered piemontite sample was Fe 3+ as indicated by the two Mössbauer doublets (isomer shift = 0.351 and 0.367 mm/s and quadrupole splitting = 2.189 and 1.93 mm/s, respectively) assigned to Fe 3+ at the M3 site. The neutron Rietveld refinement of the powder sample (R wp = 2.11%; R e = 0.88%) resulted in the occupancies of M1 [Al 0.902(5) Mn 0.098 ] and M3 [Mn 0.534(5) Fe 0.267 Al 0.20 ], where M3 Al was fixed to 0.20Al obtained by X-ray Rietveld refinement (R wp = 2.95%; R e = 2.13%). By applying the oxidation state of Fe and the distributions of Al, Fe, and Mn in the M1 and M3 sites in the powder sample, the site occupancies in the piemontite single crystal are constructed as A2 [Ca 0.711(3) Sr 0.289 ], M1 [Al 0.898(4) Mn 3+ 0.102 ] and M3 [Mn 3+ 0.633 Fe 3+ 0.316 Al 0.051 ]. The A2-O7,-O2', and-O10 distances, 2.303(2), 2.562(1), and 2.592(2) Å, respectively, are longer than those of Ca-piemontites. The mean < M3-O> and < M1-O> distances, 2.050 and 1.923 Å, respectively, are close to the published data of Ca-piemontites and Sr-rich and-bearing piemontites with Mn 3+ + Fe 3+ contents in the M3 and M1 sites similar to those of the Tone piemontite.

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Epidote-(Sr), CaSrAl2Fe3+(Si2O7)(SiO4)(OH), a new mineral from the Ananai mine, Kochi Prefecture, Japan

Cited by 13 publications

References 9 publications

日本列島付加体中に胚胎する古海洋底で生成した鉱床

日本列島付加体中に胚胎する古海洋底で生成した鉱床

Retrograde strontium metasomatism in serpentinite mélange of the Kurosegawa Zone in central Kyushu, Japan

Crystal chemistry of Sr–rich piemontite from manganese ore deposit of the Tone mine, Nishisonogi Peninsula, Nagasaki, southwest Japan

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