Chemical and Isotopic Composition of Lavas from the Northern Mariana Trough: Implications for Magmagenesis in Back-arc Basins

Gribble, R.F.; Stern, Robert J.; Newman, Sally; Bloomer, Sherman H.; O'Hearn, Timothy

doi:10.1093/petroj/39.1.125

Cited by 246 publications

(94 citation statements)

References 66 publications

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“…Thus, the two endmembers should be represented by E-MORB and newly subducted component, respectively. The Group 3 samples show high (La/Yb)cn (1.53-5.90) and low Sm/Nd ratios (0.23-0.31), comparable to those of the BABB with continental basement (e.g., Gribble et al, 1998;Shinjo et al, 1999;Sandeman et al, 2006), which is also evidenced by the discrimination results in Figs. 13a-d and 14c-d.…”

Section: Group 3: Nb-enriched Basalt From a Newly Metasomatised Wedgesupporting

confidence: 66%

“…They are characterized by "spiky" trace element patterns, with strong enrichment in LILEs and pronounced depletion in HFSEs (e.g., significant Nb-Ta, P and to lesser extent Ti). These samples have TiO 2 contents of 0.42-1.51 wt%, Nb content of 2.5-3.6 ppm, Ti/V ratios of ∼25, (Th/Nb) ratios of 1.74-6.97 and (Nb/La)n ratios of 0.15-0.41, comparable with those of the arc volcanic rocks (e.g., Gribble et al, 1998;Martin et al, 2005;Sandeman et al, 2006). Their ε Nd (t = 980 Ma) values range from +2.3 to +5.6, suggestive of derivation from a depleted mantle source.…”

Section: Group 4 Showing the Geochemical Affinity To Arc Volcanicsmentioning

confidence: 74%

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Geochronological, geochemical and Nd–Hf–Os isotopic fingerprinting of an early Neoproterozoic arc–back-arc system in South China and its accretionary assembly along the margin of Rodinia

Wang

Zhang

Cawood

et al. 2013

Precambrian Research

231

121

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Keywords:Metabasic rocks MORB-and/or arc-like geochemical signatures Earliest Neoproterozoic Arc and back-arc system Eastern South China Block Periphery of Rodinia a b s t r a c t U-Pb geochronology along with elemental and Nd-Hf-Os isotopic data from the earliest Neoproterozoic metabasic rocks within the Cathaysia Block of the South China Block (SCB) constrain the tectonic setting and paleogeography of the block within the Rodinia supercontinent. The metabasic rocks give zircon U-Pb ages of 969-984 Ma, ε Hf (t) values of +1.8 to +15.3 and Hf model ages of 0.92-1.44 Ga. They are subalkaline basalts that can be geochemically classified into four groups. Group 1 has low Nb contents (1.24-4.33 ppm), highly positive ε Nd (t) values (+4.3 to +5.2), and REE and multi-elemental patterns similar to fore-arc MORB-type basalt. Group 2 has Nb contents ranging from 3.13 ppm to 6.48 ppm, ε Nd (t) of +3.1 to +6.2, low Re and Os contents and high initial Os isotopic ratios, and displays an E-MORB geochemical signature. Group 3 has Nb = 7.18-29.87 ppm, Nb/La = 0.60-1.40, Nb/U = 5.0-37, Ce/Pb = 1.1-6.6, ε Nd (t) = +2.9 to +7.0, 187 Re/ 188 Os = 5.87-8.87 and ␥Os (t) = 178-772, geochemically resembling to the Pickle Nb-enriched basalt. Group 4 has strong LREE/HREE and HREE fractionation and high ε Nd (t) values (+2.3 to +5.6), and is characterized by similar element patterns to arc volcanic rocks. Serpentinites coeval to Group 4 show 187 Os/ 188 Os of 0.1143-0.1442 and ␥Os (t) of −7.8 to +0.1. Groups 1 and 2 are interpreted to originate from the N-MORB and E-MORB-like sources with the addition of an arc-like component, genetically linked to fore-and back-arc settings, respectively. Groups 3 and 4 show inputs of newly subduction-derived melt and fluid in the wedge source. These geochronological and geochemical signatures fingerprint the development of an earliest Neoproterozoic (∼970 Ma) arc-back-arc system along the Wuyi-Yunkai domain of the Cathaysia Block. Regional relationships indicate that the Wuyi-Yunkai arc-back-arc system was one of a series of separate convergent margin settings, which included the Shuangxiwu (∼970-880 Ma) and Jiangnan (∼870-820 Ma) systems that developed in the SCB. The formation and closure of these arc-back-arc systems resulted in the northwestwardly episodic amalgamation of various pieces of the Yangtze and Cathaysia to finally form the SCB. These signatures require the SCB to occupy an exterior accretionary orogen along the periphery of Rodinia during 990-820 Ma, rather than to have formed through Mesoproterozoic Sibao orogenesis within the interior of Rodinia.

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Section: Group 3: Nb-enriched Basalt From a Newly Metasomatised Wedgesupporting

confidence: 66%

Section: Group 4 Showing the Geochemical Affinity To Arc Volcanicsmentioning

confidence: 74%

Geochronological, geochemical and Nd–Hf–Os isotopic fingerprinting of an early Neoproterozoic arc–back-arc system in South China and its accretionary assembly along the margin of Rodinia

Wang

Zhang

Cawood

et al. 2013

Precambrian Research

231

121

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“…% (except for sample TG08-06), which are similar to those of basalts from backarc basins (0.7-2 wt. %, Pearce and Peate, 1995;Gribble et al, 1996Gribble et al, , 1998Leat et al, 2000;Fretzdorff et al, 2002;Sinton et al, 2003). Concentrations of MnO and P 2 O 5 are less than 0.5 wt.…”

Section: Major Elementsmentioning

confidence: 95%

Petrology and geochemistry of metabasalts from the Taoxinghu ophiolite, central Qiangtang, northern Tibet: Evidence for a continental back-arc basin system

Wu¹,

Cai²,

Xu³

et al. 2016

AJES

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Newly discovered ophiolitic metabasalts in the Taoxinghu area of central Qiangtang on the Qinhai-Tibet Plateau, here described for the first time, have important implications for reconstructions of the tectonic history of the Paleo-Tethys Ocean. Most of the metabasalts belong to the tholeiitic basalt series and most have undergone greenschist-facies metamorphism. The distribution of rare earth elements and trace elements shows that the rocks are typical of sub-continental margin arc-basin lavas, similar to the environment of formation of the present-day Okinawa lava, suggesting that the Taoxinghu metabasalts represent the upper portions of a supra-subduction zone (SSZ)-type ophiolite that formed in a continental back-arc basin tectonic environment. The Taoxinghu metabasalts are mainly sourced from a depleted spinel mantle-source region, with a spinel lherzolite content equivalent to partial melting of 6 %-25 %. In addition, lava compositions were likely affected by melting of sediments during subduction, while the influence of aqueous fluids was minor. Combining with the existing knowledge on the ophiolites of Longmuco-Shuanghu-Lancang suture zone (LSLSZ), an evolutionary model is proposed. The LSLSZ Paleo-Tethys Ocean basin may have started to form during the Cambrian or earlier, and subducted in the early Carboniferous. As subduction proceeded, a continental back-arc basin was developed, the site of generation of most of the Taoxinghu metabasalts. The LSLSZ Paleo-Tethys Ocean finally closed in the Triassic.

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“…The mantle array is defined by many oceanic basalts and a bulk Earth value for 87 Sr/ 86 Sr can be obtained from this trend. Data for back-arc basin basalts -BABB (shaded field) compiled from Wilson (1989) and references therein, Cousens et al (1994) and references therein, Pearce et al (1995), Gribble et al (1998) and Ewart et al (1998). Data for mid-ocean ridge basalts -MORB (solid line) compiled from Wilson (1989) and references therein and Cousens et al (1994), references therein and Peate et al (1997).…”

Section: Tectonomagmatic Significance Of Tholeiitic Basaltsmentioning

confidence: 99%

“…B -Th-Nb/16-Hf/3 diagram (Wood 1980); A -normal mid-ocean ridge basalts (N-MORB), B -enriched MORB (E-MORB) and within-plate tholeiites (WPT), C -alkaline within-plate basalts (AWPB), D -calc-alkali basalts (CAB), E -island-arc tholeiites (IAT); 1 -crustal contamination, 2 -SSZ ophiolites trend, 3 -MORB ophiolites trend. Data for back-arc basin basalts -BABB (shaded field) compiled from , Weaver et al (1979), Crawford & Keays (1987), Jahn (1986), Ikeda & Yuasa (1989), Ewart et al (1994), Gribble et al (1998), Leat et al (2000), Münker (2000). C -La/10-Nb/8-Y/15 diagram (after Cabanis & Lecolle 1989); 1A -calc-alkali basalts (CAB), 1B -area of overlap between 1A and 1C (CAB, IAT), 1C -island-arc tholeiites (IAT), 2A -within plate basalts (WPB), 2B -back-arc basin basalts (BABB), 3A -intercontinental rift alkali basalts (ICRAB), 3B -enriched mid-ocean ridge basalts (E-MORB), 3C -weakly enriched midocean ridge basalts (E-MORB), 3D -normal mid-ocean ridge basalts (N-MORB).…”

Section: Tectonomagmatic Significance Of Tholeiitic Basaltsmentioning

confidence: 99%

Geochemistry, petrology and tectonomagmatic significance of basaltic rocks from the ophiolite mélange at the NW External-Internal Dinarides junction (Croatia)

Slovenec¹,

Lugović²,

Vlahović³

2010

Geologica Carpathica

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Abstract:At the NW inflexion of the Sava-Vardar Suture Zone ophiolite mélanges, known as the Kalnik Unit, form the surface of the slopes of several Pannonian inselbergs in the SW Zagorje-Mid-Transdanubian Zone. The Mt Samoborska Gora ophiolite mélange, thought to be a part of the Kalnik Unit, forms a separate sector obducted directly onto Dinaric Triassic carbonate sediments. Basaltic rocks, the only magmatic rocks incorporated in the mélange, include MiddleTriassic (Illyrian-Fassanian) alkali within-plate basalts and Middle Jurassic (uppermost Bathonian-Lower Callovian) tholeiitic basalts. The latter sporadically constitute composite olistoliths, and are geochemically divided into N-MORBlike (high-Ti basalts) and transitional MORB/IAT (medium-Ti basalts). These geochemically different rocks suggest crystallization at various tectonomagmatic settings, which is also indicated by the rock paragenesis and host clinopyroxene compositions. Alkali basalts reflect melts derived from an OIB-type enriched mantle source [Ti/V= 62.2-82.4; (La/Lu) cn = 6.4-12.8] with Nd-Sr isotope signatures close resembling the Bulk Earth [ε Nd(T=235 Ma) = + 1.6 to + 2.5]. They are recognized as preophiolite continental rift basin volcanic rocks that closely predate the opening of the Repno oceanic domain (ROD) of the Meliata-Maliac ocean system. The high-Ti and medium-Ti basalts from composite blocks derived from a similar depleted mantle source (ε Nd(T=165 Ma) =+ 6.01 vs. + 6.35) succesively metasomatized by expulsion of fluids from a subducting slab leading to a more pronounced subduction signature in the latter [Ti/V= 31.6-44.8 and (Nb/La) n = 0.67-0.90 vs. Ti/ V= 21.5-33.9 and (Nb/La) n = 0.32-0.49]. These composite blocks indicate crust formation in an extensional basin spreading over the still active subducting ridge. The majority of high-Ti basalts may represent the fragments of older crust formed at a spreading ridge and incorporated in the mélange of the accretionary wedge formed in the proto-arc-fore-arc region. The Mt Samoborska Gora ophiolite mélange represents the trailing edge of the Kalnik Unit as a discrete sector that records the shortest stage of tectonomagmatic evolution related to intraoceanic subduction in the ROD.

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Chemical and Isotopic Composition of Lavas from the Northern Mariana Trough: Implications for Magmagenesis in Back-arc Basins

Cited by 246 publications

References 66 publications

Geochronological, geochemical and Nd–Hf–Os isotopic fingerprinting of an early Neoproterozoic arc–back-arc system in South China and its accretionary assembly along the margin of Rodinia

Geochronological, geochemical and Nd–Hf–Os isotopic fingerprinting of an early Neoproterozoic arc–back-arc system in South China and its accretionary assembly along the margin of Rodinia

Petrology and geochemistry of metabasalts from the Taoxinghu ophiolite, central Qiangtang, northern Tibet: Evidence for a continental back-arc basin system

Geochemistry, petrology and tectonomagmatic significance of basaltic rocks from the ophiolite mélange at the NW External-Internal Dinarides junction (Croatia)

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