Progressive infilling of a kimberlite pipe at Diavik, Northwest Territories, Canada: Insights from volcanic facies architecture, textures, and granulometry

Moss, S.; Russell, James K.; Andrews, Graham

doi:10.1016/j.jvolgeores.2007.12.020

Cited by 36 publications

(36 citation statements)

References 39 publications

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“…The cpx and grt samples in this study commonly exceed 1 cm in size and thus are megacrysts in a non-genetic sense (Mitchell 1986).…”

Section: Megacryst Hostsmentioning

confidence: 86%

“…However, Al 2 O 3 concentrations up to ~8.0 wt% have been reported in the literature (e.g., Mitchell, 1986). Serpentine within inclusions in Cr-diopsides from LDG lies at the high-Mg# end and extends to Al 2 O 3 contents of up to ~5.0 wt%, whereas serpentine within polymineralic inclusions in Cr-pyrope can have even higher Al 2 O 3 contents (up compositions in kimberlite.…”

Section: Serpentine and Chloritementioning

confidence: 94%

“…The less common 'magmatic trend 2' is characterized by Fe-enrichment prior to an increase in Ti contents, which has been tentatively attributed to preceding crystallization of phlogopite (Mitchell 1995).…”

Section: Chromite and Spinelmentioning

confidence: 97%

“…Kimberlite chromite data show a trend of decreasing Cr# and increasing Ti contents at relatively constant Fe# (Fe/ (Fe + Mg)), which is referred to as 'magmatic spinel trend 1' according to the terminology of Mitchell (1986Mitchell ( , 1995. The less common 'magmatic trend 2' is characterized by Fe-enrichment prior to an increase in Ti contents, which has been tentatively attributed to preceding crystallization of phlogopite (Mitchell 1995).…”

Section: Chromite and Spinelmentioning

confidence: 99%

“…Chromites in polymineralic inclusions classify as titanian-magnesian-chromite (TIMAC, Mitchell (1986)) and overlap core compositions of chromite found in the kimberlite groundmass (Fig. 8).…”

Section: Chromite and Spinelmentioning

confidence: 99%

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The evolution of calcite-bearing kimberlites by melt-rock reaction: evidence from polymineralic inclusions within clinopyroxene and garnet megacrysts from Lac de Gras kimberlites, Canada

Bussweiler

Stone

Pearson

et al. 2016

Contrib Mineral Petrol

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inclusion trails surround the inclusions. In Cr-pyropes, the inclusions additionally contain Al-spinel, clinopyroxene, and dolomite. The major and trace element compositions of the inclusion phases are generally consistent with the early stages of kimberlite differentiation trends. Extensive chemical exchange between the host phases and the inclusions is indicated by enrichment of the inclusions in major components of the host crystals, such as Cr 2 O 3 and Al 2 O 3 . This chemical evidence, along with phase equilibria constraints, supports the proposal that the inclusions within Cr-diopside record the decarbonation reaction: dolomitic melt + diopside → forsterite + calcite + CO 2 , yielding the observed inclusion mineralogy and producing associated (CO 2 -rich) fluid inclusions. Our study of polymineralic inclusions in megacrysts provides clear mineralogical and chemical evidence for an origin of kimberlite that involves the reaction of high-pressure dolomitic melt with diopside-bearing mantle assemblages producing a lower-pressure melt that crystallizes a calcite-dominated assemblage in the crust.

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“…The cpx and grt samples in this study commonly exceed 1 cm in size and thus are megacrysts in a non-genetic sense (Mitchell 1986).…”

Section: Megacryst Hostsmentioning

confidence: 86%

Section: Serpentine and Chloritementioning

confidence: 94%

Section: Chromite and Spinelmentioning

confidence: 97%

Section: Chromite and Spinelmentioning

confidence: 99%

Section: Chromite and Spinelmentioning

confidence: 99%

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The evolution of calcite-bearing kimberlites by melt-rock reaction: evidence from polymineralic inclusions within clinopyroxene and garnet megacrysts from Lac de Gras kimberlites, Canada

Bussweiler

Stone

Pearson

et al. 2016

Contrib Mineral Petrol

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Kimberlite eruptions as triggers for early Cenozoic hyperthermals

Patterson

Francis

2013

Geochem Geophys Geosyst

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[1] The early Cenozoic experienced at least three short but major hyperthermals associated with disruptions of the global carbon cycle. The largest among those, the Paleocene-Eocene thermal maximum, was associated with a negative carbon isotopic excursion of~2.5% that appears to be best explained by the thermal dissociation of methane hydrates due to an initial period of warming. The cause of the initial warming has been attributed to a massive injection of carbon (CO 2 and/or CH 4 ) into the atmosphere; however, the source of the carbon is as yet unknown. The emplacement of a large cluster of kimberlite pipes at~56 Ma in the Lac de Gras region of northern Canada may have provided the carbon that triggered early warming in the form of exsolved magmatic CO 2 . Our calculations indicate that the estimated 900-1100 Pg of carbon required for the initial~3 C of ocean water warming associated with the Paleocene-Eocene thermal maximum could have been released during the emplacement of a large kimberlite cluster. The coeval ages of two other kimberlite clusters in the Lac de Gras field and two other early Cenozoic hyperthermals indicate that CO 2 degassing during kimberlite emplacement is a plausible source of the CO 2 responsible for these sudden global warming events.

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