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Incompatible element
About: Incompatible element is a research topic. Over the lifetime, 2420 publications have been published within this topic receiving 154052 citations.
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TL;DR: In this paper, the trace element compositions of amphibole and mica separated from mantle xenoliths in alkali basalts were analyzed by ICP-MS, and it was shown that amphibole can be important hosts for Nb and Ta and cannot be ignored in identifying the underlying cause of the nearly universal relative NbTa depletion of subduction-related volcanic rocks.
366 citations
TL;DR: Isolatednanoclusters, measuring about 10nm and spaced 10−50nm apart, are enriched in incompatible elements including radiogenic Pb with unusually high 207 Pb/ 206 Pbratios as discussed by the authors.
Abstract: The only physical evidence from the earliest phases of Earth’s evolution comes from zircons, ancient mineral grains that can be dated using the U‐Th‐Pb geochronometer 1 . Oxygen isotope ratios from such zircons have been used to infer when the hydrosphere and conditions habitable to life were established 2,3 . Chemical homogenization of Earth’s crust and the existence of a magma ocean have not been dated directly, but must have occurred earlier 4 . However, the accuracy of the U‐Pbzirconagescanplausiblybebiasedbypoorlyunderstood processes of intracrystalline Pb mobility 5‐7 . Here we use atomprobe tomography 8 to identify and map individual atoms in the oldest concordant grain from Earth, a 4.4-Gyr-old Hadean zircon with a high-temperature overgrowth that formed about 1Gyrafterthemineral’score.Isolatednanoclusters,measuring about 10nm and spaced 10‐50nm apart, are enriched in incompatible elements including radiogenic Pb with unusually high 207 Pb/ 206 Pbratios.Wedemonstratethatthelengthscales of these clusters make U‐Pb age biasing impossible, and that they formed during the later reheating event. Our tomography data thereby confirm that any mixing event of the silicate Earth must have occurred before 4.4Gyr ago, consistent with
356 citations
TL;DR: In this article, major element, trace element and Nd-isotope data for 30 alluvial sediments collected from 25 rivers in Queensland, E Australia were presented.
351 citations
TL;DR: The role of residual garnet during melting under mid-ocean ridges has been the subject of many recent investigations as discussed by the authors, and major thermodynamic considerations suggest that this adiabatic and trace element mineral chemistry of residual abyssal peridotites decompression melting is a polybaric process.
Abstract: The role of residual garnet during melting beneath mid-ocean ridges 1967; Bottinga & Allegre, 1978; McKenzie, 1984) Petrohas been the subject of many recent investigations To address this logical, geochemical and experimental evidence as well as issue from the perspective of melting residues, we obtained major thermodynamic considerations suggest that this adiabatic and trace element mineral chemistry of residual abyssal peridotites decompression melting is a polybaric process (O’Hara, from the Central Indian Ridge Many clinopyroxenes have ratios 1985; Klein & Langmuir, 1987; McKenzie & Bickle, of middle to heavy rare earth elements (MREE/HREE) that are 1988) The depth at which melting begins, however, is too low to be explained by melting in the stability field of spinel intensely debated (Klein & Langmuir, 1987; McKenzie peridotite alone Several percent of melting must have occurred at & Bickle, 1988; Langmuir et al, 1992; Shen & Forsyth, higher pressures in the garnet peridotite stability field Application 1995), as this has direct implications for the temperature of new trace element partitioning models, which predict that HREE of the upwelling mantle and the thickness of the generated are compatible in high-pressure clinopyroxene, cannot fully explain crust Several geochemical characteristics of MORB are the fractionation of the MREE from the HREE Further, many attributed to melting in the presence of residual garnet, samples show textural and chemical evidence for refertilization, such suggesting that the depth of onset of melting exceeds as relative enrichments of highly incompatible trace elements with >85 km (Green & Ringwood, 1970; O’Hara et al, 1971; respect to moderately incompatible trace elements Therefore, highly Takahashi, 1986): incompatible elements, which are decoupled from major and mod(1) high middle to heavy rare earth element ratios erately incompatible trace elements, are useful to assess late-stage (MREE/HREE) occur in melt inclusions in magnesian processes, such as melt entrapment, melt–rock reaction and veining olivines from Mid-Atlantic Ridge basalts (Sobolev, 1996; Moderately incompatible trace elements are less affected by such Shimizu, 1998) late-stage processes and thus useful to infer the melting history of (2) Examination of combined Lu–Hf and Sm–Nd abyssal peridotites systematics by Salters & Hart (1989) and Salters (1996) revealed subchondritic Lu/Hf values in MORB, but a long-term Lu/Hf value that is higher than chondritic These workers explained this so-called Hf paradox by a
350 citations
TL;DR: In this article, the Ferrar magmatic province was identified as a major province of the Gondwana supercontinent, and the major and trace element compositions of these low-Ti CFB's were compared to those of oceanic basalts.
347 citations