Geochemistry and Origin of Alkaline Basalts and Gabbroic Xenoliths From the Utila Island (Bay Islands, Honduras)

Kepezhinskas, Nikita; Kamenov, George D.; Foster, David A.; Heatherington, Ann L.; Kepezhinskas, Pavel

doi:10.1130/abs/2016am-277739

Cited by 3 publications

(18 citation statements)

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“…High-niobium basalts (HNBs) are best defined (Table 3, Figure 3) as sub-alkaline to alkaline (Na 2 O + K 2 O > 3.5 wt.%). [134] for high-Nb basalts [52,55,56,64,[129][130][131][132][135][136][137][138]. Boundaries between the alkaline and the subalkaline volcanic series-MacDonald and Katsura (1964) and Irvine & Baragar (1971)-are, respectively, from [139,140].…”

Section: High-nb Basaltsmentioning

confidence: 99%

“…(C) Nb versus Nb/U diagram for basaltic rocks from volcanic arcs modified after [58]; data sources: high-Nb basalts (HNB) [52,55,56,64,[129][130][131][132][135][136][137][138], arc basalts [52,136,[143][144][145][146][147][148][149][150]. (D) Sr and Nd isotopes in high-Nb basalts from Sulu arc [130], Jamaica [129], Panama and Costa Rica [56], Kamchatka [52], Baja California [55], Izu-Bonin [132] and Utila, northern Honduras [131]. Average composition of low-degree E-MORB melt is from [141].…”

Section: High-nb Basaltsmentioning

confidence: 99%

“…Fields of worldwide OIB and normal midocean ridge basalts (N-MORB) are from [52,151], respectively. [134] for high-Nb basalts [52,55,56,64,[129][130][131][132][135][136][137][138].…”

Section: High-nb Basaltsmentioning

confidence: 99%

“…Compositional fields: pc-picrobasalt, b-basalt, ba-basaltic andesite, a-andesite, d-dacite, r-rhyolite, s1-trachybasalt, s2-basaltic trachyandesite, s3-trachyandesite, t-trachyte, u1-basanite or tephrite, u2-phonotephrite, u3-tephriphonolite, ph-phonolite, f-foidite [134]. (B) Trace element compositions of high-Nb basalts from Honduras [131], Kamchatka [52] and Sulu arc [130] compared to low-degree enriched mid-ocean ridge basalt (E-MORB) melt [141] and average ocean island basalt (OIB) [142]. (C) Nb versus Nb/U diagram for basaltic rocks from volcanic arcs modified after [58]; data sources: high-Nb basalts (HNB) [52,55,56,64,[129][130][131][132][135][136][137][138], arc basalts [52,136,[143][144][145][146][147][148][149][150].…”

Section: High-nb Basaltsmentioning

confidence: 99%

“…(B) Trace element compositions of high-Nb basalts from Honduras [131], Kamchatka [52] and Sulu arc [130] compared to low-degree enriched mid-ocean ridge basalt (E-MORB) melt [141] and average ocean island basalt (OIB) [142]. (C) Nb versus Nb/U diagram for basaltic rocks from volcanic arcs modified after [58]; data sources: high-Nb basalts (HNB) [52,55,56,64,[129][130][131][132][135][136][137][138], arc basalts [52,136,[143][144][145][146][147][148][149][150]. (D) Sr and Nd isotopes in high-Nb basalts from Sulu arc [130], Jamaica [129], Panama and Costa Rica [56], Kamchatka [52], Baja California [55], Izu-Bonin [132] and Utila, northern Honduras [131].…”

Section: High-nb Basaltsmentioning

confidence: 99%

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Adakites, High-Nb Basalts and Copper–Gold Deposits in Magmatic Arcs and Collisional Orogens: An Overview

et al. 2022

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Adakites are Y- and Yb-depleted, SiO2- and Sr-enriched rocks with elevated Sr/Y and La/Yb ratios originally thought to represent partial melts of subducted metabasalt, based on their association with the subduction of young (<25 Ma) and hot oceanic crust. Later, adakites were found in arc segments associated with oblique, slow and flat subduction, arc–transform intersections, collision zones and post-collisional extensional environments. New models of adakite petrogenesis include the melting of thickened and delaminated mafic lower crust, basalt underplating of the continental crust and high-pressure fractionation (amphibole ± garnet) of mantle-derived, hydrous mafic melts. In some cases, adakites are associated with Nb-enriched (10 ppm < Nb < 20 ppm) and high-Nb (Nb > 20 ppm) arc basalts in ancient and modern subduction zones (HNBs). Two types of HNBs are recognized on the basis of their geochemistry. Type I HNBs (Kamchatka, Honduras) share N-MORB-like isotopic and OIB-like trace element characteristics and most probably originate from adakite-contaminated mantle sources. Type II HNBs (Sulu arc, Jamaica) display high-field strength element enrichments in respect to island-arc basalts coupled with enriched, OIB-like isotopic signatures, suggesting derivation from asthenospheric mantle sources in arcs. Adakites and, to a lesser extent, HNBs are associated with Cu–Au porphyry and epithermal deposits in Cenozoic magmatic arcs (Kamchatka, Phlippines, Indonesia, Andean margin) and Paleozoic-Mesozoic (Central Asian and Tethyan) collisional orogens. This association is believed to be not just temporal and structural but also genetic due to the hydrous (common presence of amphibole and biotite), highly oxidized (>ΔFMQ > +2) and S-rich (anhydrite in modern Pinatubo and El Chichon adakite eruptions) nature of adakite magmas. Cretaceous adakites from the Stanovoy Suture Zone in Far East Russia contain Cu–Ag–Au and Cu–Zn–Mo–Ag alloys, native Au and Pt, cupriferous Ag in association witn barite and Ag-chloride. Stanovoy adakites also have systematically higher Au contents in comparison with volcanic arc magmas, suggesting that ore-forming hydrothermal fluids responsible for Cu–Au(Mo–Ag) porphyry and epithermal mineralization in upper crustal environments could have been exsolved from metal-saturated, H2O–S–Cl-rich adakite magmas. The interaction between depleted mantle peridotites and metal-rich adakites appears to be capable of producing (under a certain set of conditions) fertile sources for HNB melts connected with some epithermal Au (Porgera) and porphyry Cu–Au–Mo (Tibet, Iran) mineralized systems in modern and ancient subduction zones.

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Section: High-nb Basaltsmentioning

confidence: 99%

Section: High-nb Basaltsmentioning

confidence: 99%

“…Fields of worldwide OIB and normal midocean ridge basalts (N-MORB) are from [52,151], respectively. [134] for high-Nb basalts [52,55,56,64,[129][130][131][132][135][136][137][138].…”

Section: High-nb Basaltsmentioning

confidence: 99%

Section: High-nb Basaltsmentioning

confidence: 99%

Section: High-nb Basaltsmentioning

confidence: 99%

See 3 more Smart Citations

Adakites, High-Nb Basalts and Copper–Gold Deposits in Magmatic Arcs and Collisional Orogens: An Overview

et al. 2022

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Mineralogy of Platinum Group Elements in Explosive Breccias of the Poperechnoe Deposit (Malyi Khingan, Russia)

Mochalov¹,

Berdnikov²,

Galankina³

et al. 2023

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The results of detailed study of the platinum-group minerals (PGM) from explosive breccias of the Poperechnoe Fe-Mn deposit (the Lesser Khingan Range, Russian Far East) are presented. Native PGMs are dominated by isoferroplatinum; rutheniridosmine, native iridium, platinum, and osmium are less com-mon. Micron-sized segregations of laurite, bowieite, сuproiridsite, cuprorhodsite, hollingworthite, as well as new mineral phases of (Ir,Rh,Os)7 (S,As)13 , (Rh,Ir,Ru) 7(S,As) 13, and Pd 3(Sb,As) were recognized as micro-inclusions in isoferroplatinum and on the surface of its grains. It is shown that the studied PGMs are derived from rocks of ultramafic formations: (1) vein pyroxenites, harzburgites, and dunites of metamorphic and cumulative complexes of the most depleted peridotite varieties of the suprasubduction wedge of island-arc ophiolites and (2) vein pyroxenites of cumulative high-pressure ultramafic complexes of the basement of the ensialic island arc and products of evolution of suprasubduction mantle melts. In terms of PGE contents, the compositions of isoferroplatinum from explosive breccias are divided into four groups: group I: isoferroplatinum of fluid-metamorphogenic genesis from harzburgite, group II: isoferroplatinum of fluid-metamorphogenic genesis from dunites and magmatogenic-fluid-metasomatic genesis from vein pyrox-enites; group III: isoferroplatinum of magmatogenic genesis from chromitites of dunites of the cumulative complex; and group IV: isoferroplatinum with an elevated Pd content, which is likely derived from the melt formed by explosive breccias. Three scenarios of PGM occurrence in the fluid-saturated andesite-dacite melt of explosive breccias at the Poperechnoe deposit are discussed: (1) directly from early ultramafic com-plexes in suprasubduction settings; (2) from the reservoir of ancient platinum placer deposits; and (3) from a mantle wedge above the Mesozoic subduction zone during the generation of initial island-arc melts. The first two petrogenetic models suggest «rejuvenation» of the 190Pt-4He age of isoferroplatinum grains as a result of the thermal effect of the andesite-dacite melt to the age of 125 ± 21 Ma. The third geodynamic scenario suggests that the Lower Cretaceous age of isoferroplatinum marks the processes of metamorphogenic-metasomatic transformation of the dunite-harzburgite mantle wedge and probably corresponds to the age of the subduction magmatism at the Poperechnoe Deposit in particular and within the Lesser Khingan terrane as a whole. PGM associations in andesite-dacite breccias of the Poperechnoe Deposit are a new type of potentially commercial noble-metal mineralization in the Russian Far East, while explosive breccias (fluidoliths) can be used as an exploration guide to discover PGE lode and placer deposits of volcanogenic-explosive genesis in the Russian Federation.

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Formation of Gold Alloys during Crustal Differentiation of Convergent Zone Magmas: Constraints from an AU-Rich Websterite in the Stanovoy Suture Zone (Russian Far East)

et al. 2022

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Gold is typically transported by mafic and evolved magmas into the upper crust to be deposited in shallow oxidized porphyry and epithermal environments. However, the magmatic behavior of gold is still poorly understood and warrants further attention. Additional insights into the magmatic evolution of gold and other noble metals can be provided by investigations of primitive convergent zone magmas and products of their differentiation that contain primary-textured Au-alloys. One of the best examples of such Au-rich ultramafic cumulates is the Triassic (232–233 Ma) Ildeus intrusion, which was emplaced within the Mesozoic Stanovoy subduction zone in the Russian Far East. Some websterites from the Ildeus intrusion, representing cumulates crystallized from a primitive convergent zone magma, are enriched in Au (up to 596 ppm) and contain abundant Cu-Ag-Au micro-particles. Most of these Au-alloy micro-particles display compositions similar to those previously found in explosive pyroclastic rocks in the Lesser Khingan iron district, mantle wedge peridotites in Kamchatka and Cretaceous adakites in the Stanovoy suture zone. Textural and compositional characteristics suggest that Cu-Ag-Au alloys precipitated from a primitive calc-alkaline melt during its crustal differentiation in a Mesozoic paleo-subduction zone. Some large Cu-Ag-Au grains display an internal honeycomb-like structure with alternating Cu-rich and Cu-poor zones. Heating experiments under atmospheric conditions recorded a substantial loss of Cu from primary magmatic Cu-Ag-Au alloys, which appears to be a process characteristic of oxidized hydrothermal ore systems. We suggest that the later-stage hydrothermal alteration of differentiated igneous conduits containing magmatic gold alloys results in the formation of Cu-free gold mineralization comparable to the upper crustal porphyry and epithermal environments.

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Geochemistry and Origin of Alkaline Basalts and Gabbroic Xenoliths From the Utila Island (Bay Islands, Honduras)

Cited by 3 publications

References 0 publications

Adakites, High-Nb Basalts and Copper–Gold Deposits in Magmatic Arcs and Collisional Orogens: An Overview

Adakites, High-Nb Basalts and Copper–Gold Deposits in Magmatic Arcs and Collisional Orogens: An Overview

Mineralogy of Platinum Group Elements in Explosive Breccias of the Poperechnoe Deposit (Malyi Khingan, Russia)

Formation of Gold Alloys during Crustal Differentiation of Convergent Zone Magmas: Constraints from an AU-Rich Websterite in the Stanovoy Suture Zone (Russian Far East)

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