Mesoarchean melting and Neoarchean to Paleoproterozoic metasomatism during the formation of the cratonic mantle keel beneath West Greenland

Acken, David van; Luguet, Ambre; Pearson, D. Graham; Nowell, Geoff; Fonseca, Raúl O. C.; Nagel, T.; Schulz, T.

doi:10.1016/j.gca.2017.01.006

Cited by 13 publications

(2 citation statements)

References 97 publications

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“…This has important implications on how metals are sourced from the mantle to form ore deposits in the overlying crust (Begg et al, 2010;Griffin et al, 2013;Hronsky et al, 2012;Tassara et al, 2017). To date, few studies have addressed the relationship between HSE distribution in BMS and their petrography (e.g., Alard et al, 2000Alard et al, , 2005Alard et al, , 2011Luguet et al, 2001Luguet et al, , 2004Luguet et al, 2007;Lorand et al, 2004;Delpech et al, 2012;González-Jiménez et al, 2014;Saunders et al, 2015Saunders et al, , 2016Van Acken et al, 2017) in order to define the fingerprints left at the grain-scale by each different metasomatic agent that percolated the SCLM. Despite these advances, there are significant gaps in knowledge that limit our understanding of the impact of metasomatism on HSE mobility.…”

Section: Introductionmentioning

confidence: 99%

Highly siderophile elements mobility in the subcontinental lithospheric mantle beneath southern Patagonia

Tassara

Gonzáléz-Jiménez

Reich

et al. 2018

Lithos

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Peridotite xenoliths collected from alkali basalts in the Argentinian Patagonia reveal the existence of an ancient depleted Paleoproterozoic mantle that records a subsequent multistage metasomatic history. Metasomatism is associated with carbonatite-like melts that evolved, after variable melt/rock ratio interaction, towards CO 2 -rich and Na-bearing Mg-rich (mafic) silicate, and volatile-rich alkali silicate melts. High degrees of partial melting produced strongly depleted mantle domains devoid of base-metal sulphides (BMS). Moderate degrees of partial melting and later unrelated metasomatism produced a range of slightly depleted, slightly enriched, and strongly enriched mantle domains that preserve different types of BMS. Thus, six different BMS populations were identified including typical residual Type 1A BMS enriched in Os, Ir, and Ru relative to Pt, Pd, and Au located within primary olivine and clinopyroxene, and metasomatic Type 2A BMS that are relatively enriched in Pt, Pd, Au occurring as interstitial grains. Reworking of these two types of BMS by later metasomatism resulted in the formation of a new generation of BMS (Type 1B and Type 2B) that are intimately associated with carbonate/apatite blebs and/or empty vesicles, as well as with cryptically metasomatised or metasomatic clinopyroxene. These newly formed BMS were re-enriched in Os, Pd, Au, Re and in semi-metal elements (As, Se, Sb, Bi, Te) compared to their Type 1A and Type 2A precursors. A third generation of BMS corresponds to Ni-Cu immiscible sulphide mattes entrained within Na-bearing silica under-saturated alkali melt. They occur systematically related to intergranular glass veins and exhibit distinctively near flat CI-chondrite normalised highly siderophile element patterns with either positive Pd (Type 3A) or negative Pt (Type 3B) anomalies. Our findings indicate that Os, Pd, Re and Au can be selectively transported by volatile-rich alkali silicate melts in the subcontinental lithospheric mantle. Moreover, the transport of sulphide mattes entrained in silicate melts is also an effective mechanism to produce HSE endowment in the SCLM and play an important role as precursors of fertile, metal-rich magmas that form ore deposits in the overlying crust.

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Section: Introductionmentioning

confidence: 99%

Highly siderophile elements mobility in the subcontinental lithospheric mantle beneath southern Patagonia

Tassara

Gonzáléz-Jiménez

Reich

et al. 2018

Lithos

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“…The Re-Os isotopic system has long-proven to be effective in dating melt depletion events of mantle peridotites (e.g., Walker et al, 1989;Pearson et al, 1995;Shirey and Walker, 1998;Pearson, 1999;Irvine et al, 2003;Carlson et al, 2005;Rudnick and Walker, 2009;Liu et al, 2010Liu et al, , 2011Luguet et al, 2015). However, this isotopic system is not immune to the alteration by metasomatism and refertilization (e.g., Alard et al, 2002Alard et al, , 2011Ionov et al, 2006;Luguet et al, 2007Luguet et al, , 2015Rudnick and Walker, 2009;van Acken et al, 2017). Given that Re and Os are primarily hosted by base metal sulfides (BMS) and platinum group minerals (PGM) in mantle lithologies, the element systematics including the highly siderophile elements (HSE here including Os, Ir, Ru, Pt, Pd and Re), Se and Te, particularly their ratios such as Pd/Ir and Se/Te can be utilized to trace the signature of metasomatic overprintings and evaluate the potential impact on the Os isotopic system (Luguet et al, 2001(Luguet et al, , 2003(Luguet et al, , 2004(Luguet et al, , 2015Lorand et al, 2003;6 Alard et al, 20026 Alard et al, , 2011Ackerman et al, 2009Ackerman et al, , 2016van Acken et al, 2010a, b;;Liu et al, 2010Liu et al, , 2015Liu et al, , 2016König et al, 2014;Lorand and Luguet, 2016).…”

Section: Introductionmentioning

confidence: 99%

Diamondiferous Paleoproterozoic mantle roots beneath Arctic Canada: A study of mantle xenoliths from Parry Peninsula and Central Victoria Island

Liu

Brin

Pearson

et al. 2018

Geochimica et Cosmochimica Acta

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While the mantle roots directly beneath Archean cratons have been relatively well studied because of their economic importance, much less is known about the genesis, age, composition and thickness of the mantle lithosphere beneath the regions that surround the cratons. Despite this knowledge gap, it is fundamentally important to establish the nature of relationships between this circum-cratonic mantle and that beneath the cratons, including the diamond potential of circum-cratonic regions. Here we present mineral and bulk elemental and isotopic compositions for kimberlite-borne mantle xenoliths from the Parry Peninsula and Central Victoria Island, Arctic Canada. These xenoliths provide key windows into the lithospheric mantle underpinning regions to the North and Northwest of the Archean Slave craton, where the presence of cratonic material has been proposed. The mantle xenolith data are supplemented by mineral concentrate data obtained during diamond exploration. The mineral and whole rock chemistry of peridotites from both localities is indistinguishable from that of typical cratonic mantle lithosphere. The cool mantle paleogeotherms defined by mineral thermobarometry reveal that the lithospheric mantle beneath the Parry Peninsula and Central Victoria Island terranes extended well into the diamond stability field at the time of kimberlite eruption, and this is consistent with the recovery of diamonds from both kimberlite fields. Bulk xenolith Se and Te contents, and highly siderophile element (including Os, Ir, Pt, Pd and Re) abundance systematics, plus corresponding depletion ages derived from Re-Os isotope data suggest that the mantle beneath these parts of Arctic Canada formed in the Paleoproterozoic Era, at ~2 Ga, rather than in the Archean. The presence of a diamondiferous Paleoproterozoic mantle root is part of the growing body of global evidence for diamond generation in mantle roots that stabilized well after the Archean. In the context of regional tectonics, we interpret the highly depleted mantle compositions beneath both studied 3 regions as formed by mantle melting associated with hydrous metasomatism in the major Paleoproterozoic Wopmay-Great Bear-Hottah arc systems. These ~2 Ga arc systems were subsequently accreted along the margin of the Slave craton to form a craton-like thick lithosphere with diamond potential thereby demonstrating the importance of subduction accretion in building up Earth's long-lived continental terranes.

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Effects of multi-stage rifting and metasomatism on HSE-187Os/188Os systematics of the cratonic mantle beneath SW Greenland

Aulbach

Sun

Tappe

et al. 2019

Contrib Mineral Petrol

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Mesoarchean melting and Neoarchean to Paleoproterozoic metasomatism during the formation of the cratonic mantle keel beneath West Greenland

Cited by 13 publications

References 97 publications

Highly siderophile elements mobility in the subcontinental lithospheric mantle beneath southern Patagonia

Highly siderophile elements mobility in the subcontinental lithospheric mantle beneath southern Patagonia

Diamondiferous Paleoproterozoic mantle roots beneath Arctic Canada: A study of mantle xenoliths from Parry Peninsula and Central Victoria Island

Effects of multi-stage rifting and metasomatism on HSE-187Os/188Os systematics of the cratonic mantle beneath SW Greenland

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