Geochemical Perspectives Letters最新文献_第9页

A partial melting control on the Zn isotope composition of basalts 玄武岩锌同位素组成的部分熔融控制

IF 4.9 1区地球科学

Geochemical Perspectives Letters Pub Date : 2022-09-01 DOI: 10.7185/geochemlet.2230

J. Day, F. Moynier, O. Ishizuka

{"title":"A partial melting control on the Zn isotope composition of basalts","authors":"J. Day, F. Moynier, O. Ishizuka","doi":"10.7185/geochemlet.2230","DOIUrl":"https://doi.org/10.7185/geochemlet.2230","url":null,"abstract":"Basaltic partial melts are produced in a range of tectonic settings, including fluid-assisted melting above subduction zones, decompression melting at ridges and thermally driven melting above mantle plumes. To examine the role of partial melting on Zn, isotope and abundance data are reported for modern large-degree partial melts of the mantle represented by 22 mid-ocean ridge basalts (MORB) from three ocean basins and the first data for boninites. Boninites have some of the lowest Zn abundances of all terrestrial basalts and Zn isotope compositions ( δ 66 Zn = þ 0.21 ± 0.06 ‰ ), generally lighter than for MORB ( δ 66 Zn = þ 0.28 ± 0.06 ‰ ). Accounting for partial melting, komatiites, boninites and MORB derive from mantle sources with δ 66 Zn of ∼ 0.16 ± 0.06 ‰ . Lower-degree partial melts, such as alkali basalts, can have higher δ 66 Zn, with up to ∼ 0.4 ‰ variation possible from partial melting of distinct peridotite mantle sources. Partial melting of fertile lherzolitic and depleted harzburgitic mantle sources can generate significant Zn isotope variability and should be evaluated prior to ascribing crustal, enriched or lithological components to mantle reservoirs from Zn compositions of planetary basalts.","PeriodicalId":12613,"journal":{"name":"Geochemical Perspectives Letters","volume":" ","pages":""},"PeriodicalIF":4.9,"publicationDate":"2022-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46460824","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 9

reservation of the isotope signatures in chondritic IOM during aqueous alteration 水蚀变过程中球粒岩IOM同位素特征的保留

IF 4.9 1区地球科学

Geochemical Perspectives Letters Pub Date : 2022-09-01 DOI: 10.7185/geochemlet.2233

B. Laurent, L. Remusat, J. Viennet, R. Brunetto, L. Binet, M. Holin, M. Ciocco, C. Bouvier, A. Brunelle, S. Bernard

{"title":"reservation of the isotope signatures in chondritic IOM during aqueous alteration","authors":"B. Laurent, L. Remusat, J. Viennet, R. Brunetto, L. Binet, M. Holin, M. Ciocco, C. Bouvier, A. Brunelle, S. Bernard","doi":"10.7185/geochemlet.2233","DOIUrl":"https://doi.org/10.7185/geochemlet.2233","url":null,"abstract":"Mighei-type carbonaceous chondrites (CM) figure among the most primitive objects in the solar system. Yet, they all have experienced various degrees of aqueous alteration having modified their insoluble organic matter (IOM), in a sequence that remains to be accurately constrained. Here, we exposed the IOM of Paris, the least altered CM available, to hydrothermal conditions at 150 °C for 49 days and compared the experimental residue to the IOM of two altered CMs likely originating from the same parent body as Paris, namely Aguas Zarcas and Mukundpura. The experimental residue shows a chemical and isotopic composition similar to those of Aguas Zarcas and Mukundpura IOMs, confirming that these CMs can be seen as altered counterparts of Paris. The abundance of organic radicals also increases significantly during the experiment. Isotopic hotspots do not seem to have been lost during the experiment, suggesting that the hotspots generally observed within the CM IOMs may date back from pre-accretion era. Of note, the Raman signature of the residue differs from that of the CM IOMs, highlighting the need for further experiments better mimicking asteroidal-like conditions.","PeriodicalId":12613,"journal":{"name":"Geochemical Perspectives Letters","volume":" ","pages":""},"PeriodicalIF":4.9,"publicationDate":"2022-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48969267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Enhanced continental weathering activity at the onset of the mid-Cenomanian Event (MCE) 中塞诺曼事件（MCE）开始时增强的大陆风化活动

IF 4.9 1区地球科学

Geochemical Perspectives Letters Pub Date : 2022-09-01 DOI: 10.7185/geochemlet.2231

L. Nana Yobo, A. Brandon, L.M. Lauckner, J. Eldrett, S. Bergman, D. Minisini

{"title":"Enhanced continental weathering activity at the onset of the mid-Cenomanian Event (MCE)","authors":"L. Nana Yobo, A. Brandon, L.M. Lauckner, J. Eldrett, S. Bergman, D. Minisini","doi":"10.7185/geochemlet.2231","DOIUrl":"https://doi.org/10.7185/geochemlet.2231","url":null,"abstract":"The emplacement of a Large Igneous Province (LIP) is implicated in the triggering of the Cenomanian-Turonian Oceanic Anoxic Event 2 (OAE 2). Evidence for a similar initiation mechanism for the mid-Cenomanian Event (MCE) is unclear. In this study, a reconstruction of mid-Cenomanian seawater 187 Os/ 188 Os, the first for the Western Interior Seaway, tests the competing roles of LIP versus continental weathering activity in triggering the MCE. The absence of a prolonged unradiogenic Os isotope excursion (low 187 Os/ 188 Os) at the onset of the MCE interval argues against LIP involvement in the event ’ s initiation. Rather, more radiogenic 187 Os/ 188 Os at the onset, that continues to rise to the middle of the MCE, indicates that the event was triggered by increased continental weathering. The combination of decreasing 187 Os/ 188 Os from the middle of the MCE onward, coincident with a 40 Ar/ 39 Ar age of 96.4 Ma of basalts from Ellesmere Island, Canada, is consistent with High Arctic LIP-related volcanic activity that may have contributed to the end of the MCE. These new data on the MCE thus indicate that LIP activity is not always the trigger for carbon cycle perturbation and associated climate change.","PeriodicalId":12613,"journal":{"name":"Geochemical Perspectives Letters","volume":" ","pages":""},"PeriodicalIF":4.9,"publicationDate":"2022-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44299202","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Archean age and radiogenic source for the world’s oldest emeralds 世界上最古老祖母绿的太古代和放射成因来源

IF 4.9 1区地球科学

Geochemical Perspectives Letters Pub Date : 2022-09-01 DOI: 10.7185/geochemlet.2232

R. Nicklas, J. Day, R. Alonso-Pérez

引用次数: 0

Corrigendum to “Equilibrium olivine-melt Mg isotopic fractionation explains high δ26Mg values in arc lavas” by Liu et al., 2022 刘等人的“平衡橄榄石熔体镁同位素分馏解释了弧熔岩中高δ26Mg值”更正，2022

IF 4.9 1区地球科学

Geochemical Perspectives Letters Pub Date : 2022-08-01 DOI: 10.7185/geochemlet.2226cor

X.-N. Liu, R. Hin, C. Coath, M. van Soest, E. Melekhova, T. Elliott

引用次数: 0

Corrigendum to “Oxygen limitation can trigger the production of branched GDGTs in culture” by Halamka et al., 2021 Halamka等人于2021年对“氧气限制可以触发培养中分支gdgt的产生”的更正

IF 4.9 1区地球科学

Geochemical Perspectives Letters Pub Date : 2022-08-01 DOI: 10.7185/geochemlet.2132cor

T.A. Halamka, J. McFarlin, A. Younkin, J. Depoy, N. Dildar, S. Kopf

引用次数: 0

Origin of radiogenic 129Xe variations in carbonaceous chondrites 碳质球粒陨石中放射性129Xe变化的起源

IF 4.9 1区地球科学

Geochemical Perspectives Letters Pub Date : 2022-08-01 DOI: 10.7185/geochemlet.2228

G. Avice, M. Meier, Y. Marrocchi

引用次数: 0

Siderophores and the formation of cerium anomalies in anoxic environments 铁载体与缺氧环境中铈异常的形成

IF 4.9 1区地球科学

Geochemical Perspectives Letters Pub Date : 2022-08-01 DOI: 10.7185/geochemlet.2227

D. Kraemer, M. Bau

引用次数: 2

Diversity of chondritic organic matter probed by ultra-high resolution mass spectrometry 超高分辨率质谱法探测球粒质有机物多样性

IF 4.9 1区地球科学

Geochemical Perspectives Letters Pub Date : 2022-07-01 DOI: 10.7185/geochemlet.2224

B. Laurent, J. Maillard, C. Afonso, G. Danger, P. Giusti, L. Remusat

{"title":"Diversity of chondritic organic matter probed by ultra-high resolution mass spectrometry","authors":"B. Laurent, J. Maillard, C. Afonso, G. Danger, P. Giusti, L. Remusat","doi":"10.7185/geochemlet.2224","DOIUrl":"https://doi.org/10.7185/geochemlet.2224","url":null,"abstract":"Primitive carbonaceous chondrites exhibit an unparalleled diversity in terms of their organic content, in addition to a variable degree of hydrothermal alteration. Whether this diversity results from the circulation of fluids or from a multiplicity of precursors remains an open question of prime interest to understand the formation of carbonaceous asteroids. We applied laser desorption ionization Fourier transform ion cyclotron resonance mass spectrometry (LDI-FTICR-MS) on the macromolecular carbon of recent CM carbonaceous chondrite falls, as well as Orgueil (CI) and Tarda (C2). We probed the diversity of molecular fragments released under low power laser beam. The abundance of the chemical families is correlated to the extent of aqueous alteration, which promotes a structural aromatisation. The weakly altered Paris has retained the largest chemical heterogeneity, whilst it is lost in more altered chondrites. Orgueil and Tarda insoluble organic matter share similarities; this is consistent with Tarda and Orgueil originating from the outer belt region. Applied to returned asteroidal samples, FTICR-MS may help unravelling the origin and evolution of organic compounds during the early stages of the solar system.","PeriodicalId":12613,"journal":{"name":"Geochemical Perspectives Letters","volume":" ","pages":""},"PeriodicalIF":4.9,"publicationDate":"2022-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43424031","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Equilibrium olivine-melt Mg isotopic fractionation explains high δ26Mg values in arc lavas 平衡橄榄石熔体Mg同位素分馏解释了弧熔岩中高δ26Mg值

IF 4.9 1区地球科学

Geochemical Perspectives Letters Pub Date : 2022-07-01 DOI: 10.7185/geochemlet.2226

X.-N. Liu, R. Hin, C. Coath, M. van Soest, E. Melekhova, T. Elliott

{"title":"Equilibrium olivine-melt Mg isotopic fractionation explains high δ26Mg values in arc lavas","authors":"X.-N. Liu, R. Hin, C. Coath, M. van Soest, E. Melekhova, T. Elliott","doi":"10.7185/geochemlet.2226","DOIUrl":"https://doi.org/10.7185/geochemlet.2226","url":null,"abstract":"We determined equilibrium Mg isotope fractionation between olivine and melt ( Δ 26/24 Mg Ol/melt ) in five, naturally quenched, olivine-glass pairs that were selected to show clear textural and chemical evidence of equilibration. We employed a high-precision, critical mixture double-spiking approach to obtain a weighted mean of Δ 26/24 Mg Ol/melt = − 0.071 ± 0.010 ‰ , for values corrected to a common olivine-glass temperature of 1438 K. As function of temperature, the fractionation can be expressed as Δ 26/24 Mg Ol/melt = ( − 1.46 ± 0.26) × 10 5 / T 2 . The samples analysed have variable H 2 O content from 0.1 to ∼ 1.2 wt. %, yet no discernible difference in Δ 26/24 Mg Ol/melt was evident. We have used this Δ 26/24 Mg Ol/melt to revisit the puzzling issue of elevated Mg isotope ratios in arc lavas. In new Mg isotope data on sample suites from the Lesser Antilles and Mariana arcs, we show that primitive samples have MORB-like Mg isotope ratios while the evolved samples tend to have isotopically heavier compositions. The magnitude of this variability is well explained by olivine fractionation during magmatic differentiation as calculated with our new equilibrium Δ 26/24 Mg Ol/melt .","PeriodicalId":12613,"journal":{"name":"Geochemical Perspectives Letters","volume":" ","pages":""},"PeriodicalIF":4.9,"publicationDate":"2022-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41644095","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 8