Metasomatism and Melting in Carbonated Peridotite Xenoliths from the Mantle Wedge: The Gobernador Gregores Case (Southern Patagonia)

Laurora, Angela; Mazzucchelli, Maurizio; Rivalenti, Giorgio; Vannucci, R.; Zanetti, Alberto; Barbieri, M. Adelaide; Cingolani, Carlos Alberto

doi:10.1093/petrology/42.1.69

Cited by 149 publications

(99 citation statements)

References 63 publications

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“…% of clinopyroxene provides evidence that the mantle column beneath the Paso de Indios is signicantly depleted with respect to the modal composition of the Primitive Mantle proposed by Johnson et al [32] (Figure 3). This tendency appears in the majority of Patagonian occurrences of mantle xenoliths [8,10,28,41,42]. The possible relationship of the overall depleted character with episodes of partial melting can be inferred from the relative variation of orthopyroxene (Opx) versus clinopyroxene (Cpx) in the analyzed samples as shown in the Cpx/Opx vs. Cpx plot.…”

Section: Discussionmentioning

confidence: 99%

Short-scale variability of the SCLM beneath the extra-Andeanback-arc (Paso de Indios, Argentina): Evidence from spinel-faciesmantle xenoliths

et al. 2015

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Cenozoic basalts carrying ultrama c mantle xenoliths occur in the Matilde, León and Chenque hills in the Paso de Indios region, Argentina. The mantle xenoliths from the Chenque and León hills mainly present porphyroclastic textures, whereas the Matilde hill xenoliths have coarse-grained to porphyroclastic textures. The equilibrium temperatures are in the range of 780 to 940• C, indicating a provenance from shallow sectors of the lithospheric mantle column that were subjected to a relatively low heat ux at Cenozoic Era. According to the modal compositions of xenoliths, the mantle beneath Matilde and León hills was a ected by greater than 22% partial melting, while less depleted peridotites occur in the Chenque suite (starting from 10% partial melting). Such an observation is con rmed by the partial melting estimates based on Cr# Sp , which vary from 8 to 14% for the selected Chenque samples and from 14 to 18% for the Matilde ones. The common melting trend is overlapped by small-scale cross cutting local trends that may have been generated by open-system processes, such as open-system partial melting and/or post partial-melting metasomatic migration of exotic Na-Cr-rich melts. The two main mineralogical reaction schemes are: i) the dissolution of pyroxenes and the segregation of new olivine in olivine-rich peridotites, and ii) the replacement of primary olivine by orthopyroxene±clinopyroxene in orthopyroxene-rich peridotites. These were produced by channelled and/or pervasive melt extraction/migration. Enhanced pyroxene dissolution is attributed to channelling of silica-undersaturated melts, whereas the replacement of primary olivine by orthopyroxene±clinopyroxene points to reaction with silica-saturated melts. Late disequilibrium reactions identi ed in the xenoliths comprise: the breakdown of orthopyroxene in contact with the host basalt, and (rarely) reaction coronae on orthopyroxene, clinopyroxene and spinel linked to glassy veins. Such features are apparently related to the injection of melt, likely during entrainment into the host basalts and ascent to the surface.

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Section: Discussionmentioning

confidence: 99%

Short-scale variability of the SCLM beneath the extra-Andeanback-arc (Paso de Indios, Argentina): Evidence from spinel-faciesmantle xenoliths

et al. 2015

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“…The involved agents may be either carbonatite melt (e.g., Yaxely et al, 1991) or carbonate -rich silicate melt (Laurora et al, 2001). This scenario can be adopted for the origin of the sample 73003 having high CaO/Al 2 O 3 ratio of ~ 2.3.…”

Section: Discussion and Conclurionsmentioning

confidence: 99%

“…The calculated clinopyroxene (Cpx) composition can be fi tted by the model if melting degree of 15%, mass infl ux rate of 0.7, and trapped melt fraction of 0.02 are adopted. The range of the putative agent of Patagonia xenoliths (shaded area; Laurora et al, 2001) is also shown. .…”

Section: Discussion and Conclurionsmentioning

confidence: 99%

Geochemical and Os isotopic characteristics of a fresh harzburgite in the Hayachine-Miyamori ophiolite: Evidence for melting under influx of carbonate-rich silicate melt in an infant arc environment

Yoshikawa

Suzuki

Shibata

et al. 2012

Journal of Mineralogical and Petrological Sciences

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Os isotopic composition ( 187Os/ 188 Os = 0.1235) of a refractory harzburgite in the Hayachine -Miyamori ophiolite is subchondritic, indicating the long -term depletion of Re. Such an unradiogenic Os isotopic signature is consistent with the less oxidized condition at subduction initiation. The major and trace element characteristics of the harzburgite, together with its petrography and relatively high modal abundance of clinopyroxene, suggest an involvement of a carbonate -rich silicate melt during melt extraction in arc setting.

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“…; McInnes and Cameron, 1994;McInnes et al, 2001) ( ) ( 1992) ( 1982) (Arai et al, 2001(Arai et al, ) ( 1983Abe et al, 2002Abe et al, ) ( 1990 (Takahashi, 1978;Abe et al, 2003 ) (Umino and Yoshizawa, 1996) (Embey Isztin et al, 1989;Vasseli et al, 1997;Demeny et al, 2004 ) ( ; Ionov et al, 1995 ) (Luhr and Aranda Gomez, 1997) (Arai et al, 2003b;Beccaluva et al, 2004 ) (Gorring and Kay, 2000;Laurora et al, 2001) (Bluztajn et al, 1995) (Brandon andDraper, 1996) ( 1973;Goto and Arai, 1987) Big Jim Complex (Kelemen and Ghiorso, 1986) 2.…”

Section: IImentioning

confidence: 99%

“…10b) (Witt Eickschen et al, 1993) (Gorring and Kay, 2000) (Hauri et al, 1993) ( Fig. 10a) ( 3) Morishita et al (2003) ( ) Laurora et al (2001) (Neumann et al, 2002 ) 2. (Johnson et al, 1990) Figure 8 LREE Ti/Zr 100 ( Fig.…”

Section: (B)mentioning

confidence: 99%

Petrography and Geochemistry of the mantle xenoliths: Implications for lithospheric mantle beneath the Japan arcs

なつ江

章司²

2005

Japanese Magazine of Mineralogical and Petrological Sciences

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Recent developments in instrumentation for in situ trace element analysis of peridotite minerals give us valuable data set of petrological and geochemical insights of the upper mantle. Here, we summarize petrographical, petrological and geochemical characteristics of mantle xenoliths from the Northeastern and Southwestern Japan arcs. They have clear correlations between microtexture and mineral compositions in terms of both major and trace elements. That suggests that influx assisted melt extraction occurs simultaneously with deformation/recrystalization in the upper mantle. Their characteristics of trace elements in clinopyroxene are distinguished from those of abyssal peridotite and peridotite xenoliths from continental regions. The geochemistry of Japan arcs clinopyroxenes have characteristics of arc type mantle source; i.e., low light rare earth element (LREE) and high field strength element (HFSE; Ti, Zr and so on), rather high heavy rare earth (HREE) relative to LREE elements and Sr concentrations. They also have a rather constant Ti/Zr ratio, variable REE patterns, and relatively low LREE/HREE ratios. The simple melt extraction model can not explain these characteristics. These features are due to metasomatism, which is different from carbonatite metasomatism.

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Metasomatism and Melting in Carbonated Peridotite Xenoliths from the Mantle Wedge: The Gobernador Gregores Case (Southern Patagonia)

Cited by 149 publications

References 63 publications

Short-scale variability of the SCLM beneath the extra-Andeanback-arc (Paso de Indios, Argentina): Evidence from spinel-faciesmantle xenoliths

Short-scale variability of the SCLM beneath the extra-Andeanback-arc (Paso de Indios, Argentina): Evidence from spinel-faciesmantle xenoliths

Geochemical and Os isotopic characteristics of a fresh harzburgite in the Hayachine-Miyamori ophiolite: Evidence for melting under influx of carbonate-rich silicate melt in an infant arc environment

Petrography and Geochemistry of the mantle xenoliths: Implications for lithospheric mantle beneath the Japan arcs

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