Stages Of Intrusion Research Articles

Investigation on the unsteady-state two-phase fluid transport in the nano-pore system of natural tight porous media

Fluid transport across the natural tight micro-nanometer porous media governs numerous subsurface geological and industrial activities. The unsteady-state two-phase fluid flow at the very initial stage of non-wetting phase fluid intrusion, governing the hydrocarbon accumulation and CO2 geological sequestration process, remains uncertain. A modified unsteady-state pressurization gas displacement experiment incorporating systematic pore structure description combining mercury porosimetry, nuclear magnetic resonance, and X-ray computed tomography is conducted on the tight sandstone cores to investigate the fluid flow behaviors and to uncover their pore-scale controls. The results indicate that the unsteady-state gas–water flow deviates from Darcy’s law, in which the threshold for the onset of continuous non-wetting phase fluid intrusion (ISTP) can be observed and degree of water movement and gas intrusion strongly depend on the injection pressure. Analyses under circular pore assumption, water layer distribution model based on DLVO theory, effective flow assumption, and overall pore connectivity evaluation suggest that the water movement and gas accessibility increases are dominated by the water displacement in the free water layer zone when injection pressure < ISTP, while the criticality of continuous gas intrusion is determined by the water movement in the inner layer of weakly bound water zone located in the narrow parts of the connected pathways, especially that in the pores < 40 nm, but its increment mainly occurs in the out layer of the weakly bound water zone when injection pressure > ISTP. Distinctions in the distributions and proportions of free and bound water layers in the different connected pore systems lead to the significant variations in the ISTP, water mobility, and gas accessibility of tight sandstone. The primary reasons for the differences in the static fluid mobility and flow behaviors lay in the differed structural attributes of connected pore systems. The narrowing, heterogeneity increase, and actual flow length increment of the connected pathways will raise the resistance for continuous non-wetting phase flow and lead to losses in water mobility, accessibility of non-wetting phase fluid, and flow velocity in the unsteady-state two-phase fluid flow. The high sensitivity of the dynamic fluid flow and gas accessibility to tortuosity of the connected pore system suggests the unsteady-state two-phase fluid flow behaviors are under the coupled control of pore size, complexity, and heterogeneity.

New geochemical and isotopic (Rb-Sr and Sm-Nd) data for the rocks of the alkali-ultrabasic massif Kondyor of the Aldan Shield (Khabarovsk Territory, Russia)

The chemical composition and Rb-Sr and Sm-Nd isotope characteristics of various rocks that make up the alkali-ultramafic Kondyor massif of the Aldan Shield were studied: dunites, clinopyroxenites, gabbro, kosvites, alkaline syenites. Ultrabasic rocks of the early stage (dunites, clinopyroxenites) have a significant metasomatic alteration associated with the intrusion of a dike complex of alkaline rocks. The petrochemical features of dunites and clinopyroxenites indicate that these rocks are cumulative phases that successively crystallized from picritic melt at an early stage of the formation of the massif. Gabbro and kosvites of the marginal series were formed from the residual melt after the crystallization of dunites and clinopyroxenites. The Rb-Sr and Sm-Nd isotopic characteristics in the rocks of the early intrusion stage (dunites, clinopyroxenites, gabbro) indicate that these rocks were formed with the participation of the host rock contamination processes. The isotope-geochemical characteristics of the rocks of the dike complex (kosvites and alkaline rocks of the dunite core) indicate that these rocks crystallized from a deep melt that was not significantly contaminated by the continental crust. Differences in isotopic characteristics between ultramafic rocks and rocks of the dike complex of the dunite "core" - kosvites and alkaline rocks, suggest at least two sources of melts that participated in the formation of the Konder massif: (1) an early, deep-seated melt that formed ultrabasic rocks at the upper level, and also kosvites, plagioclase pyroxenites and gabbro of the outer “ring” with a significant degree of contamination; (2) late, differentiated (monzonite and alkaline-syenite) deep-seated melt (far from the contaminant) that became the source of kosvite and alkaline rock dikes in the central part of the Konder massif.

Simulation of the Multi-Timescale Stratospheric Intrusion Processes in a Typical Cut-Off Low over Northeast Asia

This study used the FLEXPART-WRF trajectory model to perform forward and backward simulations of a cut-off low (COL) event over northeast Asia. The analysis reveals the detailed trajectories and sources of air masses within the COL. Their trajectories illustrate the multi-timescale deep intrusion processes in the upper troposphere and lower stratosphere (UTLS) caused by the COL. The processes of air intrusion from the lower stratosphere to the middle troposphere can be divided into three stages: a slow descent stage, a rapid intrusion stage and a relatively slow intrusion stage. A source analysis of targeted air masses at 300 hPa and 500 hPa shows that the ozone-rich air in the COL primarily originated from an extratropical cyclone over central Siberia and from the extratropical jet stream. The sources of air masses in different parts of the COL show some differences. These results can help explain the ozone distribution characteristics in the main body of a COL at 300 hPa and at 500 hPa that were revealed in a previous study.

КИБЕРШАБУЫЛДАРДЫ ТАНУ ҮШІН ШЕШІМДЕРДІ ҚОЛДАУ ЖҮЙЕЛЕРІ ТУРАЛЫ БІЛІМ БАЗАСЫН ҚАЛЫПТАСТЫРУ МОДЕЛЬДЕРІ

Patterns of Bayesian networks (BN) have been developed for the computing core of the decision support system (DSS) in the course of threats prediction and stages of intrusion into information and communication networks (ICN) of informatization objects. The proposed Bayesian networks (BN) templates allow one to operate with a variety of random variables and determine the probability of a cyber threat or a specific stage of an invasion under given conditions. Probabilistic models for detecting network intrusions based on the use of dynamic Bayesian networks (DBN) have been added. The training of Bayesian networks parameters based on the EM-algorithm was carried out. In contrast to existing solutions, the proposed approach makes it possible not only to take into account the main stages of intrusions but also to make more reasonable decisions based on the use of both typical intrusion patterns and newly synthesized patterns. All templates and models make up the decision support system (DSS) computing core for intrusion detection. The effectiveness of the developed models was tested on test samples that were not previously used in training.

Distribution of sulfides and PGE minerals in the picritic and taxitic gabbro-dolerites of the Norilsk 1 intrusion

ABSTRACT Disseminated ores in the Norilsk 1 intrusion were studied to elucidate the typomorphic features of sulfides and noble metal mineralizations in picritic and taxitic (or lower olivine) gabbro-dolerites. The former are characterized by the development of a low-sulfur sulfide association (troilite, Fe-rich pentlandite, talnakhite, chalcocite, native copper) while the latter exhibits a high-sulfur association (monoclinic pyrrhotite, Ni-rich pentlandite, pyrite, heazlewoodite). The contact between these types of rocks is geochemically and mineralogically contrasting. The mineralogical and geochemical zoning directed from the roof to the base of each layer is expressed by an increase in the Cu content (and chalcopyrite) in ores, an increase in the concentration of Ni in pentlandite and S in pyrrhotite in line with a decrease of the crystallization temperature, and an increase in sulfur fugacity in the same direction. Zoning of Pd(Pt) mineralization in picritic and taxitic (olivine) gabbro-dolerites is uniform and characterized by the distribution of Pd-Sn compounds in the upper parts (together with Pd-Pb minerals in picritic rocks) and Pd-As compounds in the lower parts of the sections according to a drop in temperature. Such reverse zoning contradicts the typical mechanism of differentiation by fractional crystallization, and possibly suggests a fluid-magmatic nature. Mineralogical and geochemical features in platinum group element-Cu-Ni-bearing rocks are consistent with the idea that different stages of multi-pulse intrusions of mafic-ultramafic magmas with different compositions formed the picritic and taxitic gabbro-dolerites of the Norilsk region.

Sheeted intrusion of granitic magmas in the upper crust – Emplacement and thermal evolution of the Guandacolinos pluton, NW Argentina

The Lower Carboniferous Guandacolinos pluton of northwestern Argentina (Western Sierras Pampeanas) preserves field, structural, and petrological evidence of sheet-like transport and assembly of granitic magmas in the upper crust. The pluton is a relatively small (~24 km2) subduction-related granitic body, elongated in map view, and hosted in Neoproterozoic metamorphic rocks. Exceptional exposure records a subparallel array of steep NNE-SSW trending structures, including steep contacts partly concordant with host rock structure, numerous sheets of granite separated by host rock rafts, abundant xenoliths, and magmatic and solid-state foliations. Along the eastern half of the pluton, the granite is massive and host rock inclusions are less abundant. Regional markers of the host rock are deflected along a concordant bulged contact in the northeastern region of the pluton. Field relations indicate emplacement by multiple material transfer processes including fracture propagation, magma wedging, stoping, and lateral shortening. Contrasting mechanisms imply a changing mechanical response of host rock and multiple stages of intrusion. Emplacement began with dominant brittle fracturing and intrusion of sheets influenced by host rock anisotropies, followed by a viscoelastic phase were larger batches of magma caused downward transfer of stoped blocks, lateral expansion, and minor ductile deformation of the host rock. Thermal modelling indicates that the construction of the pluton required lateral accretion rates in the order of dm/years and less than a few tens of thousands of years to form. This case study documents the ability of incrementally assembled sheeted intrusions to efficiently heat rocks of the upper crust and trigger conditions favourable for transfer and storage of magma.

Manhole intrusion detection system with notification stages

Appropriate design of intrusion detection systems is extremely important to safeguard critical and valuable infrastructure. Telecommunications companies (TELCOs) and electric power utilities are experiencing an increased rate of rampant underground copper cable theft and vandalism. This paper addresses the important subject of combating the physical intrusion of critical infrastructure by proposing a low-cost, effective and unique manhole intrusion detection system. Manholes are openings to confined underground spaces that are used to access critical underground infrastructure and utilities such as sewer systems, electricity and telecommunication networks for maintenance and inspection. Critical infrastructure protection is very essential to avoid losses and incapacitations that would have a debilitating effect on economic activities, security, public health and safety, and so on. The increasing rate of rampant copper theft and vandalism could be attributed to the increased demand and high prices for copper on the black market. Critical infrastructure sectors such as TELCOs, electricity supply, water and rail transport are utilizing intrusion detection systems that only trigger an alarm when the critical infrastructure has already been vandalized or stolen. In this paper, we propose a low-cost and unique manhole intrusion detection system with notification stages devoted to safeguard critical infrastructure. Simulations of the system were performed before hardware implementation. The proposed system utilizes an Arduino Uno microcontroller and multiple sensors to trigger the intrusion stages early before the copper cables are vandalized. Due to the inclusion of three different additional sensors, the proposed system has an advantage of timely or early-stage intrusion detection. The response time is improved since the first alert is sent early before the actual cutting of the cable. The GSM messaging system is utilized as the alert mechanism during the intrusion stages. Notifications are also displayed on a local LCD.

Petrology of ijolite series rocks from the Prairie Lake (Canada) and Fen (Norway) alkaline rock-carbonatite complexes

This study reports the mineralogy and petrology, together with the major and trace element composition of pyroxenes, garnets and apatite from ijolite series rocks occurring at the Prairie Lake carbonatite complex, northwestern Ontario, with comparative data for ijolites from the Fen complex, Norway. The ijolites and calcite ijolites (hollaites) of Prairie Lake record the effects of magma mixing, crystal settling, solid-state re-equilibration and deuteric alteration. The Prairie Lake complex was formed by at least three stages of intrusion. The initial stage was predominantly biotite pyroxenite and associated coarse carbonatite veins. The second stage is represented primarily by members of the ijolite series together with meta-ijolites created by solid state re-equilibration of previously crystallized rocks. Differentiation of the magmas which formed the ijolite suite resulted in the formation of calcite ijolites (hollaites) and malignites (potassic nepheline syenites). The final stage was the intrusion of the heterogeneous carbonatites derived from different batches of carbonatite related magmas. These rocks contain xenoliths of ijolite suite rocks, pyroxene apatitite, wollastonite apatitite, and phoscorite.Pyroxene compositions show an evolutionary trend from diopside in biotite pyroxenites through Fe-enriched diopside-augite in ijolites to aegirine in malignites. Clinopyroxene major and trace element data show that the cores of clinopyroxene in biotite pyroxenites formed as antecrysts at depth and were emplaced as part of a later event. Trace element data from pyroxenes, garnets and apatite from Prairie Lake and Fen are similar to each other and those found in carbonatite complexes worldwide. It is proposed that a continuously-filled fractionating magma chamber was not present at Prairie Lake and that the ijolite–malignite members of the complex formed as result of small intrusions of nephelinitic magma into pre-existing ijolites. Similar styles of magmatic evolution by fractional crystallization are indicated for the Prairie Lake, Fen, and Belaya Zima ijolite‑carbonatite complexes and there is no evidence that liquid immiscibility played any role in their petrogenesis.

U‐Pb Zircon and Re‐Os Molybdenite Geochronology of the W‐Mo Mineralized Region of South Qinling, China, and their Tectonic Implications

AbstractA W‐Mo mineralized region is located along the northern margin of the South Qinling tectonic belt of China. W‐Mo mineralization occurs mainly in Cambrian–Ordovician clastic and carbonate rocks, and the ore bodies are structurally controlled by NW–SE‐ and NNE–SSW‐striking faults. Evidence for magmatism in the area is widespread and is dominated by intermediate–felsic intrusives or apophyses, such as the Dongjiangkou, Yanzhiba, Lanbandeng, and Sihaiping granitic bodies. Quartz‐vein‐type mineralization and fault‐controlled skarn‐type mineralization dominate the ore systems, with additional enrichment in residual deposits. At present, there are few or insufficient studies on (1) the age of mineralization, (2) the relationship between intermediate–felsic granite and W‐Mo mineralization, (3) the source of ore‐forming materials, and (4) the metallogenic and tectonic setting of the mineralized area. In this paper, we present geochronology results for numerous intrusive granitic bodies in the South Qinling tectonic belt. U‐Pb zircon geochronology of the Lanbandeng monzogranite and Wangjiaping biotite monzogranite yields ages of 222.7 ± 2.3 and 201.9 ± 1.8 Ma, respectively. In contrast to the Late Triassic age of the Lanbandeng monzogranite, the age of the newly discovered Wangjiaping biotite monzogranite places it at the Triassic–Jurassic boundary. Re‐Os molybdenite geochronology on the Qipangou W‐Mo deposit yielded a model age of 199.7 ± 3.9 Ma, indicating the deposit formed in the early Yanshanian period of the Early Jurassic. Granitoid intrusions in the mineralized area are characterized by composite granite bodies that crystallized at ca. 240–190 Ma. While there were multiple stages of intrusion, most occurred at 210–220 Ma, with waning magmatic activity at 200–190 Ma. The Re‐Os age of molybdenite in the region is ca. 200–190 Ma, which may represent a newly discovered period of W‐Mo metallogenesis that occurred during the final stages of magmatism. The heat associated with this magmatism drove ore formation and might have provided additional ore‐forming components for metallogenesis (represented by the Wangjiaping biotite monzogranite). Ore materials in the mineralized area were derived from mixed crustal and mantle sources. Enrichment of the region occurred during intracontinental orogenesis in the late Indosinian–Yanshanian, subsequent to the main Indosinian collision. At this time, the tectonic environment was dominated by extension and strike‐slip motion.

Anatomy and evolution of a migmatite-cored extensional metamorphic dome and interaction with syn-kinematic intrusions, the Mykonos-Delos-Rheneia MCC

Post-orogenic extension in back-arc regions is classically associated with metamorphic core complexes (MCCs) cored with exhumed metamorphic rocks and granitic intrusions interacting with low-angle detachments. When additional heat is provided by the advected asthenosphere below the extending region, for instance above slab tears, high-temperature migmatite-cored metamorphic domes and composite intrusions are emplaced whose geometry and kinematics of emplacement are controlled by regional extension and by detachments. The Cyclades Archipelago (Aegean Sea) hosts several such Miocene high-temperature MMCs intruded by Miocene granitoids, offering windows open on the interactions of intrusions with the Livada and Mykonos detachments, two branches of the North Cycladic Detachment System. Deformation associated with North Cycladic Detachment System has been described detailed on Mykonos based on a structural study of the deformation of the Mykonos pluton, but the high-temperature gneiss core of the MCC and the root zone of the intrusion have received little attention. Based on field surveys of the neighboring islands of Rheneia and Delos, we propose in this paper a new geological map and show that the locally migmatitic core of the MCC that extends from Rheneia to the Apollonia peninsula on Mykonos, is topped by a 500 m-thick low-angle shear zone, the Rheneia Shear Zone, coeval with the intrusion of a series of granitoids evolving from granodiorite to monzogranite. The Rheneia Shear Zone shows progressive flattening and shearing, with a constrictional component, during the intrusion of numerous fine-grained felsic dykes at various stages that are totally transposed to become parallel to the main regional foliation. The migmatitic core and the intrusion are intensely stretched with an E–W trending lineation and folds with axes parallel to the lineation. Structural compatibility between the migmatites and the intrusion show that the rheological parameters were not much different at the time of intrusion. The same deformation continued during cooling of the dome while new batches of granitic material intruded the colder gneiss. The granites show syn-kinematic stretching at the magmatic stage and after cooling, leading to full homoaxiality between the magmatic fabric and the mylonites below the Livada and Mykonos Detachment. From the stage of lower crustal partial melting and subsequent intrusion to mylonitization and formation of the brittle Mykonos detachment, deposition of the supra-detachment Miocene sediments and the late intrusion of baryte-iron dykes, the same kinematics is observed until a change in the stress regime some 9 Ma ago. The Mykonos-Delos-Rheneia MCC illustrates the continuous interactions between a detachment system and a growing pluton and how a discrete magmatic event can be influenced by long-term tectonics.

“I turn to you as I would turn to Nauck”: Correspondence of Viktor Jernstedt (1854–1902) and Ulrich von Wilamowitz-Moellendorff (1848–1931)

While working on the correspondence of Ulrich von Wilamowitz-Moellendorff with Russian scholars in the summer of 2021, the author discovered two letters of Viktor Jernstedt to Wilamowitz in the mss. collection of Niedersächsische Staats- und Universitätsbibliothek Göttingen. Wilamowitz’ part of this correspondence, three letters under the shelfmark call number 733.2.44 1r–6r, dated between June 1894 and August 1895, was likewise preserved among the papers of Jernstedt in the St Petersburg Branch of the Archive of the Russian Academy of Sciences. Jernstedt’s letters and Wilamowitz’ two replies are transcribed for the first time and published here. Some details that should aid understanding of the letters are offered in the notes. The transcription of Wilamowitz’ notoriously difficult hand is, even in the most hopeless cases, possible, and, apart from minor abiding problems, unequivocal. While abstaining from a full critical commentary on the problem of intrusive stage directions discussed in the letters, and not wishing to take sides, the author would like to draw the readers’ attention to the way in which the gulf between the two approaches to criticism is wont to be left unbridged, however sound and convincing the arguments coming from the opposite side are.

Geochemical Evidence for Thickening and Thinning of Lower Crust beneath the Jiaodong Peninsula: Implications for Late Mesozoic Destruction of the Eastern North China Craton

Abstract The eastern North China Craton (NCC) has been recognised as undergoing cratonic destruction during the Mesozoic; however, the mechanism of its destruction is still unclear. The main difference between the proposed models is whether the lower continental crust (LCC) underwent thinning. In this study, we conducted comprehensive analyses of Late Mesozoic felsic intrusive rocks, including Late Jurassic granites (166–146 Ma), Early Cretaceous granodiorites (136–123 Ma), and latest Early Cretaceous granites (123–108 Ma) from the Jiaodong Peninsula, located on the southeastern margin of the NCC. These rocks allowed us to investigate variations in the LCC thickness in this region and to further discuss the destruction mechanism of the eastern NCC. Here, temporal variations in crustal thickness can be tracked using whole-rock La/Yb ratios of the felsic intrusive rocks. Our study shows that the continental crust in the eastern NCC thickened during the Late Jurassic (&amp;gt;40 km) due to compression and the westward subduction of the Palaeo-Pacific Ocean lithosphere beneath the NCC since the Early Jurassic. The continental crust further thickened during the Early Cretaceous, caused by the steepening of the subducting slab after ~144 Ma that produced crustal underplating of mantle-derived melts in an extensional setting. However, the continental crust thinned (20–40 km) during the latest Early Cretaceous, caused by the rollback of the subducting slab after ~123 Ma. The geochemical compositions of three stages of felsic intrusions also suggest that the regional tectonic stress that affects the eastern NCC altered from a compressional to an intraplate extensional environment after ~144 Ma. Thus, the Late Mesozoic destruction of the eastern NCC and its accompanying magmatism were controlled by prolonged thermomechanical-chemical erosion due to low-angle subduction, steepening, and rollback of the Palaeo-Pacific Oceanic lithosphere.

Mapping of Intrusive Complex on a Small Scale Using Multi-Source Remote Sensing Images

Multi-stage intrusive complex mapping plays an important role in regional mineralization research. The similarity of lithology characteristics between different stages of intrusions necessitates the use of richer spectral bands, while higher spatial resolution is also essential in small-scale research. In this paper, a multi-source remote sensing data application method was proposed. This method includes a spectral synergy process based on statistical regression and a fusion process using Gram–Schmidt (GS) spectral sharpening. We applied the method with Gaofen-2 (GF2), Sentinel-2, and Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data to the mapping of the Mountain Sanfeng intrusive complex in northwest China in which Carboniferous intrusions have been proven to be directly related to the formation of Au deposits in the area. The band ratio (BR) and relative absorption band depth (RBD) were employed to enhance the spectral differences between two stage intrusions, and the Red-Green-Blue (RGB) false colour of the BR and RBD enhancement images performed well in the west and centre. Excellent enhancement results were obtained by making full use of all bands of the synergistic image and using the Band Ratio Matrix (BRM)-Principal Component Analysis (PCA) method in the northeast part of the study area. A crucial improvement in enhancement performance by the GS fusion process and spectral synergy process was thus shown. An accurate mapping result was obtained at the Mountain Sanfeng intrusive complex. This method could support small-scale regional geological survey and mineralization research in this region.

Elevated groundwater concentrations of arsenic and chromium in ultramafic environments controlled by seawater intrusion, the nitrogen cycle, and anthropogenic activities: The case of the Gerania Mountains, NE Peloponnese, Greece

This study aimed to investigate the role of seawater intrusion, nitrogen (N)-cycle, and anthropogenic activities on the elevated groundwater concentrations of oxyanion-forming trace elements in an ultramafic environment and to study the factors controlling the hydrogeochemical characteristics of groundwater in a broader, ultramafic-dominated area of the Gerania Mountains in NE Peloponnese, Greece. Sixty-eight groundwater samples from the a) Schinos area, b) Loutraki area, and c) springs in the Gerania Mountains were analysed for an extensive set of physical and chemical parameters. Elevated concentrations of As, up to 15 μg/L, along the coastline in the Schinos area, and abnormally high concentrations of Cr6+, up to 460 μg/L, in the central part of the Schinos area, were recorded. The strong spatial correlation of Cr6+, NO3-, and P in the central part of the Schinos area, indicated that the release and subsequent oxidation of geogenic Cr in groundwater can be triggered by N and P anthropogenic inputs, such as a) septic tank effluents or N-bearing fertilisers that lead to nitrification and subsequent soil acidification and drive Cr3+ oxidation by the NO2−/NO3− redox couple and b) P-bearing fertilisers that cause the desorption of anionic Cr6+ with simultaneous PO43- adsorption and contribute additional Cr and other trace elements to the soils. Unlike Cr, geogenic As follows a different pattern of groundwater release mechanism, which is driven by seawater intrusion and initial stages of denitrification along a flowpath near the Schinos coastline, as pointed out by the strong positive correlation coefficient between As and Cl− (0.78). The increased salinity controls the mobilisation of As and other oxyanion-forming trace elements, such as B, Se, and V, resulting in their elevated groundwater concentrations through a) their desorption from the surface of Fe/Mn-oxyhydroxides under alkaline pH conditions, b) the reductive dissolution of Fe/Mn-oxyhydroxides under local hypoxic conditions, and c) an increase in the ionic strength of groundwater favouring the dissolution of Fe/Mn-oxyhydroxides.

Magnetic Fabric and Geochronology of a Cambrian “Isotropic” Pluton in the Neoproterozoic Araçuaí Orogen

AbstractThe Araçuaí Orogen (AO) has been interpreted as a Neoproterozoic example of a large, “hot” orogen, based on a broad zone (250 km) of midcrustal metamorphic assemblages with a long, 70‐Myr history of crustal melting and episodic magmatism throughout the late Neoproterozoic and earliest Paleozoic. Here, we present results of U‐Pb sensitive high‐resoution ion microprobe (SHRIMP) zircon dating and detailed anisotropy of magnetic susceptibility (AMS) study on a late Cambrian, bimodal pluton related to final period of collapse of the AO. New U‐Pb zircon ages constrain the crystallization age of different suites within the Santa Angélica Pluton, 506 ± 3 Ma for the early felsic phase and 498 ± 5 Ma for the mafic core. New AMS data indicate that the emplacement of the Santa Angélica Pluton corresponds to two coupled plutons with concentric structures arrayed about a twin, bull's eye pattern. During the final stages of intrusion, upward relative movement of the northeastern lobe exposed the deeper levels of the intrusion, relative to the more shallowly eroded southwestern lobe. These observations suggest that magma emplacement was controlled by magma buoyancy forces, with little influence of regional tectonic stress. This behavior contrasts with the well‐defined, tectonic‐controlled fabrics of coeval plutons occurring to the north which was still hot, therefore highlighting the contrasting thermal evolution between different sectors of the orogen during its final stages.

Genes with bast fiber-specific expression in flax plants - Molecular keys for targeted fiber crop improvement

Plant fibers, owing to their unique properties, have been used by mankind for the production of textiles and composite materials for thousands of years. Currently, the use of plant fibers in various innovative fields has become very popular as they are an environmentally friendly, biodegradable, and renewable resource. Each of the numerous fiber-consuming industrial fields has special demands on the properties of fiber. The quality of plant fibers is a multicomponent parameter that depends on morphological and anatomical characteristics, as well as on the structure and proportions of fiber bundle chemical constituents. These features are formed during plant ontogenesis and can be subjected to management by manipulating the key stages of fiber development: fiber elongation by intrusive growth and cell wall thickening. To determine the molecular keys for manipulating certain fiber features related to crop quality, we summarized the RNA-Seq data obtained for different flax tissues and revealed the genes specifically upregulated in bast fibers. These genes were additionally subdivided into three groups considering the differential expression of the genes at the stage of fiber intrusive elongation versus the stage of cell wall thickening. The first group included genes specifically expressed in fibers without differential expression at the two stages. The second included those upregulated at the intrusive elongation stage compared to the further stage of development, and the third included those upregulated at tertiary cell wall deposition. The qPCR analysis of the expression level of the selected genes in fibers isolated from the developing plants of several varieties of fiber and linseed, Linum usitatissimum, as well as of two wild flax species revealed that the samples cluster into different groups in accordance with bast fiber yield and quality. The genes with tissue- and stage-specific characters of expression provide new insights into the mechanisms of fiber development and may serve as a target for molecular-genetic modulation of crop quality, as there is a high possibility of exclusively affecting bast fiber parameters, without influencing other tissues.

Two stages of granitoid intrusions and their implications on the early Paleoproterozoic tectonic evolution of the Quanji Massif

Tectonic regimes took different forms worldwide during the early Paleoproterozoic, ranging from a slowing or halting of plate tectonics to vigorous subduction-related magmatism. A detailed study is conducted on the Delingha granitoid pluton in the Quanji Massif of northwestern China to reveal the crustal evolution of this Precambrian microcontinent and to provide potential insight on complex and heterogeneous evolutionary processes occurring in this period. The Delingha pluton was mainly composed of gneissic biotite granite and gneissic granodiorite, which formed at ca. 2.48 – 2.44 Ga and 2.38 – 2.35 Ga, respectively, as evidenced by LA-ICP-MS zircon U-Pb ages. The gneissic biotite granite exhibited high-K I-type granite affinities and variable zircon εHf(t) values (−12.9 −4.7) with a major peak of approximately 2.8 and a secondary peak of approximately 3.9, indicating that the source rock was dominated by heterogeneous mafic crustal materials. The gneissic granodiorite shows A-type granite affinities and a nearly unimodal distribution of zircon εHf(t) values (−3.1 −4.0, with a peak of approximately 1.5). These data indicate that the gneissic granodiorite was mainly sourced from Archean mafic igneous rocks. Our study suggests that the gneissic biotite granite formed in a subduction-related environment while the gneissic granodiorite formed in a post-collisional tectonic regime. Alongside previous studies on other Siderian granitoids in the Quanji Massif, we propose a tectonic evolution model, including (1) plate subduction occurring before 2.44 Ga; (2) a collision occurring from ca. 2.43 to ca. 2.40 Ga; (3) a post-collisional extension occurring from ca. 2.39 to ca. 2.32 Ga. This tectonic evolution reveals that the operation of plate tectonics continued during the Siderian and that a slowdown or pause might have occurred in the Quanji Massif after ca. 2.3 Ga.

Systematically Improving Espresso: Insights from Mathematical Modeling and Experiment

Summary Espresso is a beverage brewed using hot, high-pressure water forced through a bed of roasted coffee. Despite being one of the most widely consumed coffee formats, it is also the most susceptible to variation. We report a novel model, complimented by experiment, that is able to isolate the contributions of several brewing variables, thereby disentangling some of the sources of variation in espresso extraction. Under the key assumption of homogeneous flow through the coffee bed, a monotonic decrease in extraction yield with increasingly coarse grind settings is predicted. However, experimental measurements show a peak in the extraction yield versus grind setting relationship, with lower extraction yields at both very coarse and fine settings. This result strongly suggests that inhomogeneous flow is operative at fine grind settings, resulting in poor reproducibility and wasted raw material. With instruction from our model, we outline a procedure to eliminate these shortcomings.

High oxidation magmatic evolution in the Naruo porphyry Cu deposit, Tibet, China

The Naruo porphyry Cu deposit is the third largest deposit discovered in the Duolong metallogenic district. Previous research has focused mainly on the geochemistry of the ore-bearing granodiorite porphyry; the metallogenesis remains poorly understood. In the present work, on the basis of outcrops and drilling core geological mapping, phases of early mineralization diorite, two inter-mineralization granodiorite porphyries, and late-mineralization granodiorite porphyry have been distinguished. Furthermore, the alteration zones were outlined, and the vein sequence was identified. The diorite and three porphyry phases were subjected to Laser Ablation Inductively Coupled Plasma Mass Spectrometry (La–ICP–MS) zircon U–Pb dating and in situ Hf isotope analyses as well as bulk major element, trace element, and Sr–Nd isotopic analyses. Molybdenite Re–Os dating was also conducted.The zircon U–Pb dating results show that the diorite and porphyry intrusions were emplaced at about 120 Ma, and the molybdenite Re–Os isochron age is 118.8 ± 1.9 Ma; this indicates that the Naruo porphyry Cu deposit was formed during a continuous magmatic–hydrothermal process. All of the diorite and granodiorite porphyry samples showed arc magmatic characteristics. Moreover, the moderate (87Sr/86Sr)i ratios and low εNd(t) and εHf(t) values of the diorite and porphyry intrusions suggest the source region of the juvenile lower crust. The lower (87Sr/86Sr)i and (143Nd/144Nd)i ratios and higher εNd(t) values and incompatible element concentrations than those in the granodiorite porphyry samples indicate a two-stage magmatic generation process for the intrusions. The early mineralization diorite has a high Cu concentration, implying that the source is enriched in Cu. However, the slightly lower Cu content of the late-mineralization granodiorite porphyry samples might imply Cu release from magmas and deposition within the metallogenic stage. The multiple stages of intrusions and subsequent volcanism within the Duolong metallogenic district, together with high Sr/Y features, indicate persistent magmatism during the metallogenic epoch, which is necessary for maintaining the activity of magmatic–hydrothermal and mineralization processes. Thus, the high Cu content in the source region, mantle-derived melt upwelling, and multiple stages of persistent magmatism were favorable for the formation of the Naruo porphyry Cu deposit.The high Fe2O3/FeO ratios of the diorite and granodiorite porphyry intrusions show very high oxidation features, which is coincident with estimated magmatic oxidation state calculated by the zircon trace element compositions. The high oxidation facilitates sulfur and chalcophile metals to be scavenged into the magmatic–hydrothermal systems, which is crucial for the metallogenesis of the Naruo porphyry Cu deposit.

Crystal fractionation of contaminated melts and re-melting of newly underplated basaltic crust generated Late Triassic andesitic and dioritic intrusions in the southern Yidun Terrane, SW China

The genesis of andesitic and dioritic rocks in continental arcs is hotly debated, and proposed models include slab melting, juvenile mafic lower-crustal melting, mafic and felsic magma mixing, and mantle-derived melts that underwent a MASH (melting, assimilation, storage, and homogenization) process. The controversy comes from the possibility of their polygenesis and the ambiguity of bulk-rock isotope tracers, not to mention the processes of magma evolution. Here, we report on our investigations in the southern Yidun Terrane (a Triassic continental arc in SW China) into the petrogenesis of two stages of the dioritic Xiuwacu intrusions (phases 1 and 2), the mafic microgranular enclaves (MMEs) hosted by the phase 1 intrusion, as well as the andesitic Hongshan intrusions. We used U-Pb zircon dating, in situ zircon Hf-O isotope analyses, bulk-rock Sr-Nd isotope analyses, and trace element analyses of the zircons from different stages of the intrusions and the MMEs to shed light on their sources and mantle–crust interactions involved in their petrogenesis. Our results suggest that the Xiuwacu MMEs from the phase 1 intrusion crystallized from a melt. Their variable zircon Hf-O isotopic compositions (εHf(t) = +0.4 to +5.3 and δ18O = 4.80‰ to 7.79‰) indicate they were formed by the mixing of mantle-derived basaltic melts and felsic melts. The phase 1 intrusion have an origin similar to that of the MMEs, as indicated by their homogeneous zircon Hf-O isotopic compositions (εHf(t) = +1.3 to +3.9 and δ18O = 6.58‰ to 7.31‰), which fall within the range of the isotopic compositions of the MMEs. The discovery of several inherited zircons and a small recrystallized felsic microgranular enclave hosted by an MME reveals that the MMEs contain relatively more felsic components. Even so, the MMEs still have lower silica contents (62.1–63.4 wt%) than those of the phase 1 intrusion (63.4–70.5 wt%), and this indicates that direct magma mixing of basaltic and felsic melts generated the andesitic MMEs, whereas a crystal fractionation process is required for the dioritic phase 1 intrusion. The porphyritic phase 2 and Hongshan intrusions formed at ~216 Ma, after the phase 1 intrusion, and they had higher oxygen fugacities and crystallization temperatures than the phase 1 intrusion. Given the conclusions of previous researchers that slab breakoff probably occurred at ~216 Ma, we propose that the Xiuwacu phase 2 and Hongshan intrusions formed during the slab breakoff process, the former by partial melting of the newly underplated basaltic lower crust in the MASH zone, and the latter by differentiation of mantle-derived basaltic melts at relatively high pressures.