《岩石学杂志》为在火成岩和变质岩石学和岩石发生的广泛领域发表高质量研究提供了一个国际论坛。发表的论文涵盖了主量元素、微量元素和同位素地球化学以及应用于岩石成因的年代学等领域的广泛主题；实验岩石学；岩浆生成、分化和就位过程；成岩矿物及其共生的定量研究；有助于解决基本岩石学问题的火成岩和变质岩的区域研究；岩石成因过程的理论模型。

The Journal of Petrology serves as an international forum for publishing high-quality research in the broad fields of igneous and metamorphic petrology and rock formation. The published papers cover a wide range of topics, including major and trace element geochemistry, isotopic studies, and geochronology applied to rock genesis; experimental petrology; processes of magma generation, differentiation, and emplacement; quantitative studies of diagenetic minerals and their associations; regional studies of igneous and metamorphic rocks that contribute to solving fundamental petrological issues; and theoretical models of rock formation processes.

《Journal of Petrology》是一个国际论坛，致力于发表关于火成岩和变质岩石学及其形成过程的高质量研究。该期刊涵盖了多个领域的主题，包括主量元素、微量元素和同位素地球化学，以及应用于岩石成因的年代学；实验岩石学；岩浆生成、分化和就位过程；成岩矿物及其共生的定量研究；以及有助于解决基本岩石学问题的火成岩和变质岩的区域研究。此外，期刊还探讨岩石成因过程的理论模型。

Journal of Petrology

Voluminous peraluminous leucogranites are common in large-scale orogenic belts and are crucial in gaining a fuller understanding of the related geodynamic process. However, the origin of such syn-collisional leucogranites remains highly controversial. In this contribution, we report petrological and geochemical data for Paleocene (c. 63 Ma) garnet-bearing, two-mica granites and associated biotite granites from the Gangdese batholith in southern Tibet. The Zhengga biotite granites have high SiO2 (70–73 wt %) and low MgO (0·4–0·7 wt %) contents with initial 87Sr/86Sr ratios of 0·7049–0·7050, εNd(t) values of +0·5 to +1·2 and zircon δ18O values of 5·6–6·9‰, similar to most early Paleocene granitoids in southern Lhasa. These geochemical characteristics suggest that the Zhengga biotite granites were derived from a crustal source that mixed with variable amounts of Gangdese juvenile lower crust and minor ancient crust-derived melts. The Zhengga peraluminous, garnet-bearing, two-mica granites have similar Sr–Nd–O isotope compositions to the biotite granites (0·7037–0·7050, +0·4 to +0·8, 5·5–7·3‰, respectively) as well as higher SiO2 (73–76 wt %) and lower TiO2 (<0·06 wt %), MgO (<0·3 wt %), Fe2O3T (<2 wt %) and CaO (<0·7 wt %) contents. These most probably represent highly evolved biotite granite magmas that differentiated in the mid-crust. The first contact of India with Asia appears to have occurred in central Lhasa during the early Paleocene (65–63 Ma) and led to crustal thickening and cessation of magmatism. Early Paleocene slab roll-back would have significantly enhanced asthenospheric corner flow and supplied a long-lived heat source for coeval crustal anatexis and metamorphism in southern Lhasa during the early phase of continental collision. Similar interaction between continental collision and oceanic subduction may also occur in other large-scale convergence zones in which the lithosphere and crust are anomalously hot.

Lin Ma

Qiang Wang

Andrew C Kerr

Jin-Hui Yang

Xiao-Ping Xia

Quan Ou

Zong-Yong Yang

Peng Sun

Paleocene (c. 62 Ma) Leucogranites in Southern Lhasa, Tibet: Products of Syn-collisional Crustal Anatexis during Slab Roll-back?

西藏拉萨南部古新世（约62 Ma）白岗岩：板块回撤期间同碰撞地壳熔融的产物？

Xenoliths of subducted crustal origin hosted by Miocene ultrapotassic igneous rocks in the southern Pamir provide important new information regarding the geological processes accompanying tectonism during the Indo-Eurasian collision. Four types have been studied: sanidine eclogites (omphacite, garnet, sanidine, quartz, biotite, kyanite), felsic granulites (garnet, quartz, sanidine and kyanite), basaltic eclogites (omphacite and garnet), and a glimmerite (biotite, clinopyroxene and sanidine). Apatite, rutile and carbonate are the most abundant minor phases. Hydrous phases (biotite and phengite in felsic granulites and basaltic eclogites, amphiboles in mafic and sanidine eclogites) and plagioclase form minor inclusions in garnet or kyanite. Solid-phase thermobarometry reveals recrystallization at mainly ultrahigh temperatures of 1000–1100°C and near-ultrahigh pressures of 2·5–2·8 GPa. Textures, parageneses and mineral compositions suggest derivation of the xenoliths from subducted basaltic, tonalitic and pelitic crust that experienced high-pressure dehydration melting, K-rich metasomatism, and solid-state re-equilibration. The timing of these processes is constrained by zircon ages from the xenoliths and 40Ar/39Ar ages of the host volcanic rocks to 57–11 Ma. These xenoliths reveal that deeply subducted crust may undergo extensive dehydration-driven partial melting, density-driven differentiation and disaggregation, and sequestration within the mantle. These processes may also contribute to the alkaline volcanism observed in continent-collision zones.

BRADLEY HACKER

PETER LUFFI

VALERY LUTKOV

VLADISLAV MINAEV

LOTHAR RATSCHBACHER

TERRY PLANK

MIHAI DUCEA

ALBERTO PATIÑO-DOUCE

MICHAEL McWILLIAMS

JIM METCALF

Near-Ultrahigh Pressure Processing of Continental Crust: Miocene Crustal Xenoliths from the Pamir

Experiments performed at 2 kbar, in the temperature range 800–1000°C, with fO2 between NNO−2·3 and NNO+2·9 (where NNO is the nickel–nickel oxide buffer), and varying amounts of sulphur added to hydrous metaluminous rhyolite bulk compositions, were used to constrain the solubility of sulphur in rhyolite melts. The results show that fS2 exerts a dominant control on the sulphur solubility in hydrous silicate melts and that, depending on fO2, a rhyolitic melt can reach sulphur contents close to 1000 ppm at high fS2. At fO2 below NNO+1, the addition of iron to a sulphur-bearing rhyolite magma produces massive crystallization of pyrrhotite and does not enhance the sulphur solubility of the melt. For a given fO2, the melt-sulphur-content increases with fS2. For fixed fO2 and fS2, temperature exerts a positive control on sulphur solubilities, at least for fO2 below NNO+1. The mole fraction of dissolved sulphur exhibits essentially linear dependence on fH2S at low fO2 and, although the experimental evidence is less clear, on fSO2 at high fO2. The minimum in sulphur solubility corresponds to the redox range where both fH2S and fSO2 are approximately equal. A thermodynamic model of sulphur solubility in hydrous rhyolite melts is derived assuming that total dissolved sulphur results from the additive effects of H2S and SO2 dissolution reactions. The model reproduces well the minimum of sulphur solubility at around NNO+1, in addition to the variation of the sulphide to sulphate ratio with fO2. A simple empirical model of sulphur solubility in rhyolitic melts is derived, and shows good correspondence between model and observations for high-silica rhyolites.

B. CLEMENTE

The Solubility of Sulphur in Hydrous Rhyolitic Melts

含水流纹质熔体中硫的溶解度

The Taupo Volcanic Zone (TVZ), New Zealand is a region of voluminous and frequent rhyolitic volcanism and widespread geothermal activity. Additionally, the hydrothermal systems of the TVZ contain relatively high concentrations of base and precious metals. Here we present an extensive dataset of major element, volatile, and trace element (including Pb, Zn, As, Mo, Cu) abundances in melt inclusions, pumice glasses and minerals from eight eruptions within the Okataina Volcanic Center (OVC) of the TVZ to investigate the behavior of metals during melt evolution. The high-SiO2 rhyolites of the OVC contain high concentrations of volatiles (≤6 wt % H2O, ≤0·25 wt % Cl) and underwent significant degassing prior to and during eruption. The OVC melts contain moderate concentrations of metals (11–24 ppm Pb, 20–50 ppm Zn, 2–7 ppm As, <2·5 ppm Mo, <∼5 ppm Cu). Ferromagnesian minerals (amphibole, biotite and orthopyroxene) in the OVC pumice have high concentrations of Zn (≤1500 ppm), and plagioclase and biotite contain moderate amounts of Pb (≤11 ppm). The melt inclusion and pumice glass trace element data reveal complex histories of magma mixing and mingling prior to eruption; however, discrete melt batches are easily identified based on trace element geochemistry. Variations in incompatible trace elements within these melt batches suggest that the OVC rhyolites underwent at least ∼20–25% fractional crystallization during quartz crystallization and melt inclusion entrapment (at pressures of ∼100–200 MPa) and little to no crystallization (≤5%) during ascent and eruption. Comparison of melt inclusion metal and incompatible element (e.g. U) concentrations reveals that melt Pb, Mo and As increase, whereas melt Zn decreases, during fractional crystallization at depth (∼100–200 MPa). These observations can be explained by minor partitioning of the metals Pb, Mo and As into the fractionating minerals and stronger partitioning of Zn into the ferromagnesian phases, supported by calculated metal D values and analyzed metal concentrations in OVC minerals. Interestingly, throughout both deep, vapor-saturated crystallization and during extensive degassing during magma ascent and eruption (as recorded by pumice glasses), the metals analyzed here do not appear to partition appreciably into the vapor. We propose that the lack of volatility of the metals analyzed in this study can be attributed to a combination of several factors. First, vapor–melt partitioning requires the presence of ligands—commonly Cl, S and OH—with which the metals may complex. Given the low Cl/H2O ratios in the OVC melts and the extensive degassing of H2O compared with Cl, it seems likely that the rhyolites would have exsolved H2O-rich vapor with insufficient Cl to transport metals (in particular Pb and Zn) into the vapor phase, either at depth or during magma ascent. Second, the overall small volumes of vapor present during crystallization at pressures of 100–200 MPa would have impeded significant vapor–melt partitioning of the metals. Finally, the estimated very rapid ascent of the OVC melts from depths of 4–8 km suggests that there was insufficient time at low pressure for diffusion of metals out of the melt. These results imply that there may be an indirect connection between the rhyolites and the metals of the hydrothermal systems of the TVZ. As the metals, and other species such as Cl, remain in the rhyolitic magmas upon eruption, they are available in the large volumes of rhyolite emplaced in the upper crust of the TVZ for leaching by heated meteoric waters.

Emily R. Johnson

Vadim S. Kamenetsky

Jocelyn McPhie

The Behavior of Metals (Pb, Zn, As, Mo, Cu) During Crystallization and Degassing of Rhyolites from the Okataina Volcanic Center, Taupo Volcanic Zone, New Zealand

新西兰陶波火山带奥卡塔纳火山中心流纹岩结晶和脱气过程中金属（铅、锌、砷、钼、铜）的行为

Abstract Deciphering deep magmatic processes driving the onset of continental break-up is fundamental to constrain our understanding of plate tectonics. The East African Rift System (EARS) is the only currently active system on Earth to study distinct stages of rift evolution. We present a coupled analysis of melt and fluid inclusions in the Virunga Volcanic Province (VVP) offering an unprecedented insight into the dynamics of incipient rifting and its evolution. Our study highlights that melting of distinct metasomes in the deep lithosphere is a common feature of immature rifts. In the VVP, it leads to the emission of nephelinitic and basanitic melts at Nyiragongo and Nyamulagira volcanoes, respectively. Additionally, the chemical composition of melt and fluid inclusions supports the identification of another magmatic series in the area. Related alkali basaltic melts would be produced by contemporary melting of a less enriched domain in the upper lithosphere, more classically documented in mature rifts. Various extents of mixing and crystallisation of these three distinct magmatic series occur in the lower crust beneath the VVP where the barometric estimates are consistent with the presence of a thick seismic low velocity zone (LVZ). The involvement of alkali basaltic melts in the regional magma production could be also detected in the spread of gas emissions in the rift valley and in the fumaroles of the main active volcanoes. Melting of the corresponding mantle domain is an added source of gas release that may largely contribute to CO2 emissions along the EARS.

G Boudoire

N Bobrowski

P -Y Burgi

S Calabrese

L France

G Giuffrida

F Grassa

K Karume

J -C Kazadi Mwepu

J Kuhn

R Moritz

O Munguiko Munyamahoro

A L Rizzo

D Tedesco

Magmatic activity in incipient continental break-up as revealed by coupling melt and fluid inclusions

初始大陆裂解中的岩浆活动：熔体与流体包裹体耦合揭示

Abstract Magmatic systems feed eruptions to the surface; lead to the formation of ore deposits; provide energy for geothermal systems; and are key to Earth’s differentiation. While it is commonly accepted that silicic magmatic systems span much of the crust, little direct evidence is available for their vertical continuity (or lack thereof), or for the spatial and temporal distribution of melt within them. In this work, we focus on Miocene plutonic and volcanic units exposed in the Colorado Extensional Corridor, SW USA. Plutonic units (Searchlight Pluton–SLP, Aztec Wash Pluton–AWP, and Spirit Mountain Batholith–SMB) consist primarily of coarse-grained granitoids rich in feldspar that can be credibly considered cumulates. Marginal facies and fine-grained dikes and sills are interpreted to record melt compositions that fed the plutons. Leucogranite dikes and roof units were likely extracted from the crystallizing plutons. The nearby Upper Highland Range Volcanics record compositions that can be interpreted as extracted from the SLP system. We use whole-rock compositions of granitoids and rhyolites to calculate extraction pressures, and glass compositions from volcanic rocks to calculate pre-eruptive storage pressures using rhyolite-MELTS. We seek pressures consistent with assemblages containing quartz+2 feldspars±magnetite±ilmenite (Q2F or Q2FMI assemblages). We use the calculated pressures to assess the distribution of magma in silicic magmatic crustal columns. The dataset reveals three main clusters of compositions and pressures: 72-74.5 wt.% SiO2, 450-370 MPa (Q2F extraction); 75.5-77 wt.% SiO2, 300-185 MPa (Q2FMI extraction and pre-eruptive storage); 77.5-78 wt.% SiO2, 180-120 MPa (Q2FMI extraction and pre-eruptive storage). Compositions attributed to cumulates (based on texture, major and trace-element compositions) do not typically yield extraction pressures, suggesting that rhyolite-MELTS can generally distinguish compositions of melts from those of cumulates. Our results show that magma distribution spanned from the middle crust to the surface, with well-defined gaps in pressure between the three groups. Magma mushes were located in the middle crust (~400 MPa, ~15 km depth), from which magmas that fed the shallow plutonic units were derived – there is no exposed record of these magma mushes, and they are inferred from extraction pressures for the less evolved fine-grained rocks. We infer two sets of discrete, shallower mush bodies that fed eruptions to the surface. The leucogranite roof zones represent bodies of melt-dominated magma that failed to erupt and instead solidified in the subsurface. Magma distribution was vertically discretized, rather than continuous as shown in most models – there were specific horizons within the crust where magma accumulation was favored, while much of the crust remained melt-free.

Guilherme A R Gualda

Calvin F Miller

Blake M Wallrich

The Rhyolite Factory: Insights from rhyolite-MELTS geobarometry of plutonic rocks and associated volcanics

流纹岩工厂：来自深成岩及其相关火山岩的流纹岩-MELTS地质压力计的启示

Abstract Maunaloa—the largest active volcano on Earth—erupted in 2022 after its longest known repose period (~38 years) and two decades of volcanic unrest. This eruptive hiatus at Maunaloa encompasses most of the ~35-year-long Puʻuʻōʻō eruption of neighboring Kīlauea, which ended in 2018 with a collapse of the summit caldera and an unusually voluminous (~1 km3) rift eruption. A long-term pattern of such anticorrelated eruptive behavior suggests that a magmatic connection exists between these volcanoes within the asthenospheric mantle source and melting region, the lithospheric mantle, and/or the volcanic edifice. The exact nature of this connection is enigmatic. In the past, the distinct compositions of lavas from Kīlauea and Maunaloa were thought to require completely separate magma pathways from the mantle source of each volcano to the surface. Here, we use a nearly 200-yr record of lava chemistry from both volcanoes to demonstrate that melt from a shared mantle source within the Hawaiian plume may be transported alternately to Kīlauea or Maunaloa on a timescale of decades. This process led to a correlated temporal variation in 206Pb/204Pb and 87Sr/86Sr at these volcanoes since the early 19th century with each becoming more active when it received melt from the shared source. Ratios of highly over moderately incompatible trace elements (e.g., Nb/Y) at Kīlauea reached a minimum from ~2000 to 2010, which coincides with an increase in seismicity and inflation at the summit of Maunaloa. Thereafter, a reversal in Nb/Y at Kīlauea signals a decline in the degree of mantle partial melting at this volcano and suggests that melt from the shared source is now being diverted from Kīlauea to Maunaloa for the first time since the early to mid-20th century. These observations link a mantle-related shift in melt generation and transport at Kīlauea to the awakening of Maunaloa in 2002 and its eruption in 2022. Monitoring of lava chemistry is a potential tool that may be used to forecast the behavior (e.g., eruption rate and frequency) of these adjacent volcanoes on a timescale of decades. A future increase in eruptive activity at Maunaloa is likely if the temporal increase in Nb/Y continues at Kīlauea.

Aaron J Pietruszka

Daniel E Heaton

Jared P Marske

Marc D Norman

Mahinaokalani G Robbins

Reed B Mershon

Kendra J Lynn

Drew T Downs

Arron R Steiner

J Michael Rhodes

Michael O Garcia

Awakening of Maunaloa Linked to Melt Shared from Kīlauea’s Mantle Source

毛纳罗亚火山苏醒与基拉韦厄火山地幔源共享熔融有关

Abstract The geochemical composition of Ocean Island Basalts (OIBs) from the Azores reflects the spatial distribution, shape, and temporal evolution of small-scale geochemical heterogeneities within their mantle plume source. Here, we investigate the time-related evolution of volcanism at São Jorge Island, Central Azores. New field observations, a magnetic survey, 40Ar/39Ar and 14C ages and geochemical data indicate that the fissural volcanic activity at São Jorge produced at least four main mafic volcanic complexes (V. C.). The oldest V. C., São João, produced the thickest lava piles at ca. 1.3 Ma in the eastern part of the island. After a period of quiescence, the Serra do Topo V. C. was produced at ca. 0.8-0.5 Ma in the central part of the island. The Rosais V. C. was emplaced between ca. 0.4 and 0.1 Ma on the entire island. Finally, the Holocene Manadas V.C. volcanism became active in the western part of the island and includes three historic eruptions (1580, 1808 and 1964 CE). Magmas were formed at low melting degrees from a peridotitic mantle with possible minor contributions of recycled components. Olivine compositions and whole-rock trace element ratios discard a significant contribution from pyroxenitic source rocks. Melting temperatures (ca. 1420-1480 °C) were slightly higher than those of the ambient upper mantle. The four V.C. are characterized by distinct geochemical compositions in terms of incompatible trace elements and Sr-Nd-Pb isotopic ratios. The oldest V.C., São João, is characterized by Pb isotopic compositions (e.g., markedly negative Δ7/4 and 8/4 values) plotting well below the Northern Hemisphere Reference Line (NHRL). The Upper Pleistocene (Rosais V.C.) lavas from the north-western cliffs have compositions similar to enriched mantle (EM) end-member basalts (e.g., high 207Pb/204Pb at moderate 206Pb/204Pb; high Ba/Nb), which are rare among northern hemisphere OIBs. Finally, high 206Pb/204Pb (up to 20), reflecting contribution from a HIMU-type component characterizes the Holocene Manadas lavas and is occasionally found in lavas from other volcanic complexes from 1.3 to 0.1 Ma. These findings indicate that magmas from São Jorge and the nearby Central Azores islands were sourced from a strongly heterogeneous mantle plume, which displayed localized filaments of heterogeneous material that were rapidly exhausted (in ca. 0.2 Ma). The dominant component at São Jorge and in the Central Azores in general appears to be the HIMU-type endmember, which instead is not significant in the Eastern Azores. Possibly, the Central and Eastern Azores were produced by distinct branches of the Azores mantle plume, as would also be consistent with previous tomographic studies.

Andrea Marzoli

José Madeira

João Mata

Angelo De Min

António Brum Silveira

Nasrrddine Youbi

Pedro Silva

Hervé Bertrand

Massimo Chiaradia

Fred Jourdan

Christine M Meyzen

Sara Callegaro

Time-Dependent Evolution and Source Heterogeneities of Ocean Island Basalts from a Weak Plume, São Jorge, Azores

弱羽流海洋岛玄武岩的时间依赖演化与源区异质性：亚速尔群岛圣若热岛

Abstract The Afar region is one of the only places on Earth where magmatic continental rifting and associated ongoing break-up processes are exposed onshore. The several active magmatic segments there are characterized by contrasted morphologies, crustal thicknesses, magma production rates, and magma-tectonic styles. In the Erta Ale Range rift segment, extension is magmatically accommodated, making the range the ideal place to study the magmatic behavior of a mature rift segment. Erta Ale Range comprises sub-segments with magma compositions ranging from basalts to rhyolites, but only the Erta Ale Volcano (EAV) sub-segment is active, where only basaltic compositions have been reported so far. Here, we show for the first time protracted differentiation at EAV that is not expressed volcanically at the surface, but is rather accessible via unique cognate gabbroic and microgabbroic blocks, and recorded by mixing with erupted basaltic magmas. These cognate samples record previously unknown mushy and evolved parts of the EAV plumbing system. To constrain their origin and evolution, we measured the major and trace element compositions of the bulk rocks, interstitial glasses, and melt inclusions. We also measured the oxygen isotopic compositions of olivine crystals, interstitial glasses, and melt inclusions. By combining these results with textural relationships and oxy-thermo-barometry calculations, we discuss magma differentiation and storage conditions, as well as magmatic interactions during transport through the crust. Comparison of our results with rhyolite-MELTS thermodynamic models highlights that protracted fractional crystallization is the main process of magma evolution, and when associated with reactive porous flow is capable of forming the evolved compositions observed (up to 75 wt.% SiO2). We also use the model outputs to quantify distinct steps of igneous differentiation in both shallow and deep crustal reservoirs, and we highlight significant interactions with hydrothermally altered wall rocks. We discuss this model within the geological contexts of the Erta Ale Range rift segment and the larger Afar region, and highlight contrasts with mature oceanic systems to argue that the region is not in the final stages of continental break-up.

Juliette Pin

Gilles Chazot

Lydéric France

Bénédicte Abily

Andrey Gurenko

Alexandra Loppin

Protracted magma evolution and transcrustal magmatic plumbing system architecture at Erta Ale volcano (Afar, Ethiopia)

埃塔阿雷火山（埃塞俄比亚，阿法尔）的长期岩浆演化及跨地壳岩浆管道系统结构

Abbreviation	J Petrology
Journal Impact	3.65
Quartiles(Global)	GEOCHEMISTRY & GEOPHYSICS(Q1)

ISSN	0022-3530, 1460-2415
h-index	195

Publication Information	Publisher: Oxford University Press，Publishing cycle: Monthly，Journal Type: journal，Open Access Journals: No
Basic data	Year of publication: 1960，Proportion of original research papers: 100.00%，Self Citation Rate:8.60%， Gold OA Rate: 21.81%
Average review cycle	网友分享经验：平均12.0个月
Average recruitment ratio	网友分享经验：一般

Journal of Petrology

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Paleocene (c. 62 Ma) Leucogranites in Southern Lhasa, Tibet: Products of Syn-collisional Crustal Anatexis during Slab Roll-back?

Near-Ultrahigh Pressure Processing of Continental Crust: Miocene Crustal Xenoliths from the Pamir

The Solubility of Sulphur in Hydrous Rhyolitic Melts

The Behavior of Metals (Pb, Zn, As, Mo, Cu) During Crystallization and Degassing of Rhyolites from the Okataina Volcanic Center, Taupo Volcanic Zone, New Zealand

Magmatic activity in incipient continental break-up as revealed by coupling melt and fluid inclusions

Magmatic activity in incipient continental break-up as revealed by coupling melt and fluid inclusions

The Rhyolite Factory: Insights from rhyolite-MELTS geobarometry of plutonic rocks and associated volcanics

Awakening of Maunaloa Linked to Melt Shared from Kīlauea’s Mantle Source

Time-Dependent Evolution and Source Heterogeneities of Ocean Island Basalts from a Weak Plume, São Jorge, Azores

Protracted magma evolution and transcrustal magmatic plumbing system architecture at Erta Ale volcano (Afar, Ethiopia)