Noble gas composition and 40Ar/39Ar age in eclogites from the main hole of the Chinese Continental Scientific Drilling project

Hopp, J.; Schwarz, Winfried H.; Trieloff, M.; Meyer, Hans‐Peter; Hanel, Michael; Altherr, Rainer

doi:10.1007/s00410-016-1290-4

Cited by 2 publications

(4 citation statements)

References 60 publications

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“…This 286" can be interpreted to result from the production of slab fluid at temperatures where Ne 287"and Ar are mobile but Kr and Xe are immobile. "Secondly,Hopp et al (2016) recently 288"…”

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confidence: 99%

Noble gases recycled into the mantle through cold subduction zones

Smye

Jackson

Konrad‐Schmolke

et al. 2017

Earth and Planetary Science Letters

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Subduction of hydrous oceanic lithosphere replenishes the mantle volatile inventory. 27" Substantial uncertainties exist on the magnitudes of the recycled volatile fluxes and it 28" is unclear whether Earth surface reservoirs are undergoing net-loss or net-gain of H 2 O 29" and CO 2. Here, we develop noble gases as tracers for deep volatile cycling. 30" Specifically, we construct and apply a kinetic model to estimate the effect of 31" subduction zone metamorphism on the elemental composition of noble gases in 32" amphibole-a common constituent of altered oceanic crust. We show that progressive 33" dehydration of the slab leads to the extraction of noble gases, linking noble gas deep 34" cycling to H 2 O. Noble gases are strongly fractionated within hot subduction zones, 35" whereas minimal fractionation occurs along colder subduction geotherms. This 36" implies that the observed Ar-Kr-Xe elemental pattern of the mantle is dominated by 37" the injection of noble gases through colder subduction zones. We estimate a present-38" day bulk recycling efficiency of 5-35% and 60-80% for 36 Ar and H 2 O bound within 39" oceanic crust, respectively. Given that hotter subduction dominates over geologic 40" history, this result highlights the importance of cooler subduction zones in regassing 41" the mantle and in affecting modern volatile budget of Earth's interior. 42" 43" Keywords 44" 1. Noble gases 45" 2. Subduction zone processes 46" 3. Mantle geochemistry 47" 4. Deep water cycle 48" 49" 50" Kendrick et al., 2011). Metasomatised mantle wedge peridotites preserve elemental 64" noble gas compositions similar to sedimentary pore fluids (Kobayashi et al., 2016; 65" Sumino et al., 2010). This implies transport of seawater-derived noble gases to depths 66" approaching arc magma genesis. Mantle-derived well gases contain noble gas 67" abundance ratios similar to those of seawater (Holland and Ballentine, 2006), which is 68" distinctive from primordial components. This finding is corroborated by isotopic 69" observations that both MORB and OIB sources contain an atmospheric signature of 70" heavy noble gas abundances attributed to subduction (Caracausi et al.,

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confidence: 99%

Noble gases recycled into the mantle through cold subduction zones

Smye

Jackson

Konrad‐Schmolke

et al. 2017

Earth and Planetary Science Letters

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“…Noble gases are investigated in fluid inclusions occurring in a variety of minerals, e.g., in olivine, pyroxene, amphibole, sulphides, or basaltic glasses; these are of interest when questions about magma origins and mantle contributions are Crustal rock studies (48) Climate studies (9) Deep water studies (4) Mantle rock studies (49) Method studies (7) Ore studies (45) Extraterrestrial rocks studies (3) TWO CRUSHER 3 Geofluids investigated. Studies of crustal composition and origin have analysed fluid inclusions found in olivine, calcite, fluorite, eclogite, corundum, quartz, or whole rock pieces (e.g., [58][59][60][61]). Common minerals relevant for noble gas analyses in fluid inclusions for ore studies are ore-associated minerals like quartz, pyrite, calcite, or fluorite (e.g., [3,40,53,62]).…”

Section: Fluid Inclusion Genesismentioning

confidence: 99%

“…Multiple crushing steps consist of slowly pressing first until the first cracks appear, then repeating the crushing until the cracking sound of the sample has stopped [9]. The first crushing step delivers most of the gases, i.e., primarily 4), up to 600 (5) [81] (1), [82] (2), [59] (3), [80] (4), [8,83] (5)…”

Section: Screw-type Crushermentioning

confidence: 99%

“…The first step involves coarse crushing of the rock specimen followed by handpicking of minerals under a binocular microscope (e.g., [53,62,76,120]). Prior to mineral selection under the microscope, crushed materials are sieved to a grain size fraction of 0.5-2 mm ( [53,76]) or >315 μm [59]. What minerals are selected depends on the type of fluid inclusions of interest; e.g., olivine is selected for their large fluid inclusions that are known to contain higher amounts of He [28].…”

Section: Number Of Crushingmentioning

confidence: 99%

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Mineral Crushing Methods for Noble Gas Analyses of Fluid Inclusions

et al. 2023

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Noble gases are frequently probed for investigating fluid inclusions in minerals to unravel rock-forming processes through time. Over the last decades, heating and crushing have been the two main methods applied for noble gas extraction from fluid inclusions in ultrahigh vacuum (about 10-9 mBar). The heating of minerals or pieces of bulk rock causes the release of noble gases from both fluid inclusions and the mineral or rock matrix, the latter due to temperature-dependent mineral dehydration. Crushing of minerals only affects fluid inclusions and allows a release of noble gases at room temperature with minor contributions from the mineral matrix. This review describes different ultravacuum crushing techniques for noble gas analysis from fluid inclusions. It examines the technical details and operational conditions of each crushing system as well as methods to prepare samples prior to crushing. Crushing systems were found to have unique designs across the different laboratories reviewed; they include single or multiple sample loadings and manual, magnetic, or hydraulic operation of the crushing pistons. Due to the small amounts of noble gases released, the technology requires several mg to a few grams of rock material to achieve a measurement of all stable noble gas isotopes in a single fluid inclusion. While theoretically all stable noble gas isotopes are of interest, the elements and isotopes reported in different studies vary widely and reference materials as well as laboratory intercomparisons are lacking. The review includes applications on the origins of magmatic rocks and geochemical processes in the Earth’s mantle, the origin and chemical composition of deep crustal fluids and how these contribute to the formation of minerals of economic interest, and paleoclimate studies based on speleothems.

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Noble gas composition and 40Ar/39Ar age in eclogites from the main hole of the Chinese Continental Scientific Drilling project

Cited by 2 publications

References 60 publications

Noble gases recycled into the mantle through cold subduction zones

Noble gases recycled into the mantle through cold subduction zones

Mineral Crushing Methods for Noble Gas Analyses of Fluid Inclusions

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