Churikova, Tatiana G.

[["dc.bibliographiccitation.firstpage","131"],["dc.bibliographiccitation.issue","1-4"],["dc.bibliographiccitation.journal","Journal of Volcanology and Geothermal Research"],["dc.bibliographiccitation.lastpage","151"],["dc.bibliographiccitation.volume","104"],["dc.contributor.author","Dorendorf, F."],["dc.contributor.author","Churikova, Tatiana G."],["dc.contributor.author","Koloskov, A."],["dc.contributor.author","Worner, G."],["dc.date.accessioned","2018-11-07T09:13:52Z"],["dc.date.available","2018-11-07T09:13:52Z"],["dc.date.issued","2000"],["dc.description.abstract","The different roles of variable mantle sources and intra-crustal differentiation processes at Bakening volcano (Kamchatka) and contemporaneous basaltic monogenetic centers are studied using major and trace elements and isotopic data. Three suites of volcanic activity are recognized: (1) plateau basalts of Lower Pleistocene age; (2) andesites and dacites of the Bakening volcano, the New Bakening volcano dacitic centers nearby; and (3) contemporaneous basaltic cinder cones erupted along subduction zone--parallel N-S faults. Age-data show that the last eruptions in the Bakening area occurred only 600-1200 years ago, suggesting the volcano is potentially active. Major element variations and petrographic observations provides evidence for a fractionation assemblage of olivine, clinopyroxene, +/-plagioclase, +/-magnetite (?) within the basaltic suite. The fractionation in the andesites and dacites is dominated by amphibole, clinopyroxene. orthopyroxene and plagioclase plus minor amounts of magnetite and apatite. The youngest cpx-opx-andesites of Bakening main volcano deviate from that trend. Their source was probably formed by mixing of basaltic magmas into the silicic magma chamber of the Bakening volcano. Overall trace element patterns as well as the Sr-Nd-Pb isotopic compositions are quite similar in all rocks despite large differences in their chemical composition (from basalt to rhyodacite). In detail however, the andesite-dacites of the central Bakening volcano show a stronger enrichment in the more incompatible elements and depletion in HREE compared to the monogenetic basaltic centers. This results in a crossing of the REE-pattern for the two suites. The decrease in the HREEs can be explained by amphibole fractionation. A slab component is less likely because it would result in fractionation of the HREE from each other, which is not observed. The higher relative amounts of LILE in the dacitic and the large scatter in the basaltic rocks must be the result of a variable source enrichment by slab-derived fluids overprinting a variable depleted mantle wedge. The plateau basalts are less depleted in HFSE and show a more fractionated HREE pattern. These lavas could either result from a slab component or the addition of an OIB-type enriched mantle in their source. (C) 2000 EIsevier Science B.V. All rights reserved."],["dc.identifier.doi","10.1016/S0377-0273(00)00203-1"],["dc.identifier.isi","000166971200008"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/27267"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Elsevier Science Bv"],["dc.relation.issn","0377-0273"],["dc.title","Late Pleistocene to Holocene activity at Bakening volcano and surrounding monogenetic centers (Kamchatka): volcanic geology and geochemical evolution"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","659"],["dc.bibliographiccitation.issue","5"],["dc.bibliographiccitation.journal","Contributions to Mineralogy and Petrology"],["dc.bibliographiccitation.lastpage","687"],["dc.bibliographiccitation.volume","159"],["dc.contributor.author","Volynets, Anna O."],["dc.contributor.author","Churikova, Tatiana G."],["dc.contributor.author","Woerner, Gerhard"],["dc.contributor.author","Gordeychik, Boris N."],["dc.contributor.author","Layer, Paul"],["dc.date.accessioned","2018-11-07T08:43:29Z"],["dc.date.available","2018-11-07T08:43:29Z"],["dc.date.issued","2010"],["dc.description.abstract","New (40)Ar/(39)Ar and published (14)C ages constrain voluminous mafic volcanism of the Kamchatka back-arc to Miocene (3-6 Ma) and Late Pleistocene to Holocene (< 1 Ma) times. Trace elements and isotopic compositions show that older rocks derived from a depleted mantle through subduction fluid-flux melting (> 20%). Younger rocks form in a back arc by lower melting degrees involving enriched mantle components. The arc front and Central Kamchatka Depression are also underlain by plateau lavas and shield volcanoes of Late Pleistocene age. The focus of these voluminous eruptions thus migrated in time and may be the result of a high fluid flux in a setting where the Emperor seamount subducts and the slab steepens during rollback during terrain accretions. The northern termination of Holocene volcanism locates the edge of the subducting Pacific plate below Kamchatka, a \"slab-edge-effect\" is not observed in the back arc region."],["dc.identifier.doi","10.1007/s00410-009-0447-9"],["dc.identifier.isi","000276276300004"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?goescholar/4176"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/19974"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Springer"],["dc.relation.issn","0010-7999"],["dc.rights","Goescholar"],["dc.rights.uri","https://goescholar.uni-goettingen.de/licenses"],["dc.title","Mafic Late Miocene-Quaternary volcanic rocks in the Kamchatka back arc region: implications for subduction geometry and slab history at the Pacific-Aleutian junction"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","3"],["dc.bibliographiccitation.journal","Journal of Volcanology and Geothermal Research"],["dc.bibliographiccitation.lastpage","21"],["dc.bibliographiccitation.volume","263"],["dc.contributor.author","Churikova, Tatiana G."],["dc.contributor.author","Gordeychik, Boris N."],["dc.contributor.author","Ivanov, Boris V."],["dc.contributor.author","Woerner, Gerhard"],["dc.date.accessioned","2018-11-07T09:21:39Z"],["dc.date.available","2018-11-07T09:21:39Z"],["dc.date.issued","2013"],["dc.description.abstract","Data on the geology, petrography, mineralogy, and geochemistry of rocks from Kamen Volcano (Central Kamchatka Depression) are presented and compared with rocks from the neighbouring active volcanoes. The rocks from Kamen and Ploskie Sopky volcanoes differ systematically in major elemental and mineral compositions and could not have been produced from the same primary melts. The compositional trends of Kamen stratovolcano lavas and dikes are clearly distinct from those of Klyuchevskoy lavas in all major and trace element diagrams as well as in mineral composition. However, lavas of the monogenetic cones on the southwestern slope of Kamen Volcano are similar to the moderately high-Mg basalts from Klyuchevskoy and may have been derived from the same primary melts. This means that the monogenetic cones of Kamen Volcano represent the feeding magma for Klyuchevskoy Volcano. Rocks from Kamen stratovolcano and Bezymianny form a common trend on all major element diagrams, indicating their genetic proximity. This suggests that Bezymianny Volcano inherited the feeding magma system of extinct Kamen Volcano. The observed geochemical diversity of rocks from the Klyuchevskaya group of volcanoes can be explained as the result of both gradual depletion over time of the mantle N-MORB-type source due to the intense previous magmatic events in this area, and the addition of distinct fluids to this mantle source. (C) 2013 Elsevier B.V. All rights reserved."],["dc.description.sponsorship","NSF; Russian Foundation for Basic Research [08-05-00600]"],["dc.identifier.doi","10.1016/j.jvolgeores.2013.01.019"],["dc.identifier.isi","000326365600002"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/29159"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Elsevier Science Bv"],["dc.relation.issn","1872-6097"],["dc.relation.issn","0377-0273"],["dc.title","Relationship between Kamen Volcano and the Klyuchevskaya group of volcanoes (Kamchatka)"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","112"],["dc.bibliographiccitation.issue","2"],["dc.bibliographiccitation.journal","Journal of Volcanology and Seismology"],["dc.bibliographiccitation.lastpage","130"],["dc.bibliographiccitation.volume","7"],["dc.contributor.author","Churikova, Tatiana G."],["dc.contributor.author","Ivanov, Boris V."],["dc.contributor.author","Eichelberger, J."],["dc.contributor.author","Woerner, Gerhard"],["dc.contributor.author","Browne, B."],["dc.contributor.author","Izbekov, P."],["dc.date.accessioned","2018-11-07T09:27:13Z"],["dc.date.available","2018-11-07T09:27:13Z"],["dc.date.issued","2013"],["dc.description.abstract","The data on the geochemistry of the rocks of Kizimen Volcano and results of microprobe studies of major and trace elements in plagioclase grains from acid lavas and basalt inclusions are presented. The characteristics of the Kizimen Volcano are the following: (1) basalt inclusions are abundant in acid lavas; (2) banded, mixed lavas occur; (3) the distribution curves of rare-earth elements of acidic lavas and basalt inclusions intersect; (4) Sr-Nd isotope systematics of the rocks and inclusions do not indicate mixture with crustal material; (5) plagioclase phenocrysts are of direct and reverse zonation; (6) olivine and hornblende, as well as acid and mafic plagioclases, coexist in the rocks. The studies revealed that the rocks are of a hybrid nature and originated in the course of repeated mixture of acid and mafic melts either with chemical and thermal interaction of melts or exclusively thermal ones. Study of the major- and trace-element distribution in zonal minerals provides an informative tool for understanding the history of the generation and evolution of melts in a magma chamber."],["dc.identifier.doi","10.1134/S0742046313020024"],["dc.identifier.isi","000318572800002"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/30486"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Maik Nauka/interperiodica/springer"],["dc.relation.issn","0742-0463"],["dc.title","Major and trace element zoning in plagioclase from Kizimen Volcano (Kamchatka): Insights into magma-chamber processes"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","11775"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","Scientific Reports"],["dc.bibliographiccitation.volume","8"],["dc.contributor.author","Gordeychik, Boris N."],["dc.contributor.author","Churikova, Tatiana G."],["dc.contributor.author","Kronz, Andreas"],["dc.contributor.author","Sundermeyer, Caren"],["dc.contributor.author","Simakin, Alexander"],["dc.contributor.author","Wörner, Gerhard"],["dc.date.accessioned","2018-12-18T10:55:41Z"],["dc.date.available","2018-12-18T10:55:41Z"],["dc.date.issued","2018"],["dc.description.abstract","Complex core-rim zoning of Mg-Fe-Ni-Ca-Cr-Al-P in high-Mg olivine crystals from a tuff ring of Shiveluch volcano, Kamchatka, enables reconstruction of the entire olivine crystallization history from mantle conditions to eruption. Bell-shaped Fo86-92 and Ni profiles in crystal cores were formed by diffusion after mixing with evolved magma. Diffusion proceeded to the centres of crystals and completely equilibrated Fo and Ni in some crystals. Diffusion times extracted from Fo and Ni core profiles range from 100 to 2000 days. During subsequent mixing with mafic mantle-equilibrated melt, the cores were partially dissolved and overgrown by Fo90 olivine. Times extracted from Fo and Ni diffusion profiles across the resorption interface between the core and its overgrowth range within 1-10 days, which corresponds to the time of magma ascent to the surface. The overgrowth shows identical smooth Fo-Ni decreasing zoning patterns for all crystals towards the margin, indicating that all crystals shared the same growth history after last mixing event prior to eruption. At the same time, Ca, and to an even greater extent Cr, Al, and P have oscillatory growth patterns in the crystals overgrowth. Our data show that magma ascent can be extremely short during maar/tuff ring eruption."],["dc.identifier.doi","10.1038/s41598-018-30133-1"],["dc.identifier.pmid","30082716"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/15442"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/57129"],["dc.language.iso","en"],["dc.notes.intern","Merged from goescholar"],["dc.notes.status","zu prüfen"],["dc.relation.eissn","2045-2322"],["dc.relation.orgunit","Fakultät für Geowissenschaften und Geographie"],["dc.rights","CC BY 4.0"],["dc.rights.uri","https://creativecommons.org/licenses/by/4.0/"],["dc.title","Growth of, and diffusion in, olivine in ultra-fast ascending basalt magmas from Shiveluch volcano"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.issue","5"],["dc.bibliographiccitation.journal","Journal of Geophysical Research. B, Solid Earth"],["dc.bibliographiccitation.volume","125"],["dc.contributor.author","Liu, Haiyang"],["dc.contributor.author","Xiao, Yilin"],["dc.contributor.author","Sun, He"],["dc.contributor.author","Tong, Fengtai"],["dc.contributor.author","Heuser, Alexander"],["dc.contributor.author","Churikova, Tatiana"],["dc.contributor.author","Wörner, Gerhard"],["dc.date.accessioned","2021-04-14T08:26:47Z"],["dc.date.available","2021-04-14T08:26:47Z"],["dc.date.issued","2020"],["dc.identifier.doi","10.1029/2019JB019237"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/82077"],["dc.language.iso","en"],["dc.notes.intern","DOI Import GROB-399"],["dc.relation.eissn","2169-9356"],["dc.relation.issn","2169-9313"],["dc.title","Trace Elements and Li Isotope Compositions Across the Kamchatka Arc: Constraints on Slab‐Derived Fluid Sources"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.issue","13"],["dc.bibliographiccitation.journal","Geochimica et Cosmochimica Acta"],["dc.bibliographiccitation.volume","73"],["dc.contributor.author","Volynets, Anna O."],["dc.contributor.author","Churikova, Tatiana G."],["dc.contributor.author","Woerner, Gerhard"],["dc.date.accessioned","2018-11-07T08:29:17Z"],["dc.date.available","2018-11-07T08:29:17Z"],["dc.date.issued","2009"],["dc.format.extent","A1393"],["dc.identifier.isi","000267229903474"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/16610"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Pergamon-elsevier Science Ltd"],["dc.publisher.place","Oxford"],["dc.relation.conference","19th Annual VM Goldschmidt Conference"],["dc.relation.eventlocation","Davos, SWITZERLAND"],["dc.relation.issn","0016-7037"],["dc.title","Mantle sources and fluids in the Northern Kamchatka back arc"],["dc.type","conference_abstract"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","275"],["dc.bibliographiccitation.issue","3-4"],["dc.bibliographiccitation.journal","Earth and Planetary Science Letters"],["dc.bibliographiccitation.lastpage","293"],["dc.bibliographiccitation.volume","224"],["dc.contributor.author","Munker, C."],["dc.contributor.author","Worner, G."],["dc.contributor.author","Yogodzinski, G."],["dc.contributor.author","Churikova, Tatiana G."],["dc.date.accessioned","2018-11-07T10:46:23Z"],["dc.date.available","2018-11-07T10:46:23Z"],["dc.date.issued","2004"],["dc.description.abstract","Models explaining the characteristic depletion of High Field Strength Elements (HFSE) relative to elements of similar compatibility in subduction zone magmas invoke either (1) the presence of HFSE-rich minerals in the subduction regime or (2) a selectively lower mobility of HFSE during subduction metasomatism of the mantle. In order to investigate the properties of HTSE in subduction regimes closer, we performed high precision measurements of Nb/Ta, Zr/Hf, and Lu/Hf ratios together with Hf-176/Hf-177 analyses on arc rocks from Kamchatka and the western Aleutians. The volcanic rocks of the Kamchatka region comprise compositional end members for both fluid and slab melt controlled mantle regimes, thus enabling systematic studies on the HFSE mobility at different conditions in the subarc mantle. Hf-Nd isotope and systematic Zr/Hf and Lu/Hf covariations illustrate that Zr-Hf and Lu are immobile in fluid-dominated regimes. Hf-Nd isotope compositions furthermore indicate the presence of \"Indian\" type depleted mantle beneath Kamchatka, as previously shown for the Mariana and Izu-Bonin arcs. In addition to a depleted mantle component, Hf-Nd isotope compositions enable identification of a more enriched mantle wedge component in the back-arc (Sredinny Ridge) that most likely consists of mantle lithosphere. The ratios of Nb/Ta and Zr/Hf are decoupled in rocks from fluid-dominated sources, indicating that Nb and Ta can be enriched in the mantle by subduction fluids to a small extent. In contrast to the fluid-dominated regime in Central Kamchatka, the budget of HFSE and Lit in rocks from the Northern Kamchatka Depression and in adakitic rocks from the western Aleutians is significantly affected by slab melts that originate from subducted oceanic crust. Compositions of the rocks with the highest slab melt components in their source (Sr/ Y>30) provide no evidence that either Nb/Ta or Zr/Hf ratios are fractionated at a globally significant scale during melting of subducted oceanic crust. Subduction processes are therefore an unlikely candidate to explain the terrestrial Nb-Ta paradox (i.e., the subchondritic Nb/Ta ratios in all accessible terrestrial silicate reservoirs). (C) 2004 Elsevier B.V. All rights reserved."],["dc.identifier.doi","10.1016/j.epsl.2004.05.030"],["dc.identifier.isi","000223582400004"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/47733"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Elsevier Science Bv"],["dc.relation.issn","1385-013X"],["dc.relation.issn","0012-821X"],["dc.title","Behaviour of high field strength elements in subduction zones: constraints from Kamchatka-Aleutian arc lavas"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","1567"],["dc.bibliographiccitation.issue","8"],["dc.bibliographiccitation.journal","Journal of Petrology"],["dc.bibliographiccitation.lastpage","1593"],["dc.bibliographiccitation.volume","42"],["dc.contributor.author","Churikova, Tatiana G."],["dc.contributor.author","Dorendorf, F."],["dc.contributor.author","Worner, G."],["dc.date.accessioned","2018-11-07T08:49:35Z"],["dc.date.available","2018-11-07T08:49:35Z"],["dc.date.issued","2001"],["dc.description.abstract","Major and trace element and Sr Nd Pb isotopic variations ill mafic volcanic rocks hve been studied in a 220 km transect across the Kamchatka are from the Eastern Volcanic Front, over the Central Kamchatka Depression to the Sredinny Ridge in the back-arc. Thirteen volcanoes and lava fields, from 110 to 400 km above the subducted slab, were sampled. This allows its to characterize spatial variations and the relative amount and composition of the slab fluid involved in magma genesis. Typical Kamchatka arc basalts, normalized for fractionation to 6% MgO. display a strong increase in large ion lithophile, light rare earth and high field strength elements from the arc front to the back-arc. Ba/Zr and Ce/Pb ratios, however, are nearly constant across the arc, which suggests a similar fluid input for Ba and Pb. La/Yb and Nb/Zr- increase from the are front to the back-arc. Rocks from the, Central Kamchatka Depression range in Sr-87/Sr-86 from 0.70334 to 0.70366, but have almost constant Nd isotopic compositions (Nd-141/Nd-144 0.51307-0.51312). This correlates with the highest U/Th ratios in these rocks. Pb-isotopic ratios are mid-ocean ridge basalt (MORB)-like but decrease slightly from the volcanic front to the back-mv. The initial mantle source ranged from N-MORB-like ill the volcanic front and Central Kamchatka Depression to more enriched in the back-arc. This enriched component is similar to all ocean-island basalt (OM) source. Variations in (CaO)(6.0)-(Na2O)(6.0) show that degree of melting decreases fi-om the arc front to the Central Kamchatka Depression and remains constant from there to the Sredinny Ridge. Calculated fluid compositions have a similar trace element pattern across the arc, although minor differences are implied. A model is prevented that quantifies the various mantle components (variably depleted, N-MORB-mantle and enriched OIB-mantle) and the fluid compositions added to this mantle wedge. The amount of fluid added ranges from 0.7 to 2.1%. The degree of melting changes from similar to 20% at the arc front to < 10% below the back-an, region. 77if, xocksfioni volcanoes qj'thc northern part of the Central Kamchatka Depression to the north of the transect considered in this study - are significantly, different in their trace element composition) compared with the other rocks of the transect and their source appear) to have been enriched by a component derived from melting of the edge of the ruptured slab."],["dc.identifier.doi","10.1093/petrology/42.8.1567"],["dc.identifier.isi","000170459600008"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/21496"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Oxford Univ Press"],["dc.relation.issn","0022-3530"],["dc.title","Sources and fluids in the mantle wedge below Kamchatka, evidence from across-arc geochemical variation"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.issue","9"],["dc.bibliographiccitation.journal","Journal of Petrology"],["dc.bibliographiccitation.volume","61"],["dc.contributor.author","Gordeychik, Boris"],["dc.contributor.author","Churikova, Tatiana"],["dc.contributor.author","Shea, Thomas"],["dc.contributor.author","Kronz, Andreas"],["dc.contributor.author","Simakin, Alexander"],["dc.contributor.author","Wörner, Gerhard"],["dc.date.accessioned","2021-06-01T09:41:56Z"],["dc.date.available","2021-06-01T09:41:56Z"],["dc.date.issued","2020"],["dc.description.abstract","Abstract Nickel is a strongly compatible element in olivine, and thus fractional crystallization of olivine typically results in a concave-up trend on a Fo–Ni diagram. ‘Ni-enriched’ olivine compositions are considered those that fall above such a crystallization trend. To explain Ni-enriched olivine crystals, we develop a set of theoretical and computational models to describe how primitive olivine phenocrysts from a parent (high-Mg, high-Ni) basalt re-equilibrate with an evolved (low-Mg, low-Ni) melt through diffusion. These models describe the progressive loss of Fo and Ni in olivine cores during protracted diffusion for various crystal shapes and different relative diffusivities for Ni and Fe–Mg. In the case when the diffusivity of Ni is lower than that for Fe–Mg interdiffusion, then olivine phenocrysts affected by protracted diffusion form a concave-down trend that contrasts with the concave-up crystallization trend. Models for different simple geometries show that the concavity of the diffusion trend does not depend on the size of the crystals and only weakly depends on their shape. We also find that the effect of diffusion anisotropy on trend concavity is of the same magnitude as the effect of crystal shape. Thus, both diffusion anisotropy and crystal shape do not significantly change the concave-down diffusion trend. Three-dimensional numerical diffusion models using a range of more complex, realistic olivine morphologies with anisotropy corroborate this conclusion. Thus, the curvature of the concave-down diffusion trend is mainly determined by the ratio of Ni and Fe–Mg diffusion coefficients. The initial and final points of the diffusion trend are in turn determined by the compositional contrast between mafic and more evolved melts that have mixed to cause disequilibrium between olivine cores and surrounding melt. We present several examples of measurements on olivine from arc basalts from Kamchatka, and published olivine datasets from mafic magmas from non-subduction settings (lamproites and kimberlites) that are consistent with diffusion-controlled Fo–Ni behaviour. In each case the ratio of Ni and Fe–Mg diffusion coefficients is indicated to be <1. These examples show that crystallization and diffusion can be distinguished by concave-up and concave-down trends in Fo–Ni diagrams."],["dc.identifier.doi","10.1093/petrology/egaa083"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/85081"],["dc.language.iso","en"],["dc.notes.intern","DOI-Import GROB-425"],["dc.relation.eissn","1460-2415"],["dc.title","Fo and Ni Relations in Olivine Differentiate between Crystallization and Diffusion Trends"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]