Inside/Outside : Post-Synthetic Modification of the Zr-Benzophenonedicarboxylate Metal–Organic Framework

The Zr-based metal–organic framework, Zr-bzpdc-MOF, contains the photoreactive linker molecule benzophenone-4,4'-dicarboxylate (bzpdc) which imparts the possibility for photochemical post-synthetic modification. Upon irradiation with UV light, the keto group of the benzophenone moiety will react with nearly every C-H bond-containing molecule. Within this paper, we further explore the photochemical reactivity of the Zr-bzpdc-MOF, especially with regard to which restrictions govern internal versus external reactions. We show that apart from reactions with C-H bond-containing molecules, the MOF reacts also with water. By studying the reactivity versus linear alcohols we find a clear delineation in that shorter alcohol molecules (up to butanol as a borderline case) react with photoexcited keto groups throughout the whole crystals whereas longer ones react only with surface-standing keto groups. In addition, we show that with the alkanes n-butane to n-octane, the reaction is restricted to the outer surface. We hypothesize that the reactivity of the Zr-bzpdc-MOF versus different reagents depends on the accessibility of the pore system which in turn depends mainly on the size of the reagents and on their polarity. The possibility to direct the post-synthetic modification of the Zr-bzpdc-MOF (selective modification of the whole pore system versus surface modification) gives additional degrees of freedom in the design of this metal–organic framework for shaping and for applications. © 2020 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA

Genesis Of The 1.45 Ga Kratz Spring Iron Oxide-Apatite Deposit Complex In Southeast Missouri, USA: Constraints From Oxide Mineral Chemistry

Seven major and numerous lesser Fe oxide occurrences within the 1.47 Ga St. Francois Mountains terrane in Missouri (USA) have previously been described as iron oxide-apatite (IOA) and iron oxide-copper-gold (IOCG) deposits. Researchers speculate that these contain significant amounts of critical minerals, most notably rare earth elements and cobalt. One of the less-studied deposits in the region is the 1.455 Ga Kratz Spring deposit. The deposit consists of two steeply dipping magnetite bodies beneath 450 m of sedimentary cover. The genesis of the Kratz Spring deposit and its relationship to nearby IOA-IOCG deposits remains poorly constrained. To better understand the formation of the Kratz Spring deposit, the authors integrated stratigraphic, petrographic, and bulk rock studies within situ trace element and Fe isotope chemistry of magnetite and hematite. These data show that the Kratz Spring deposit is hydrothermal in origin but is divided into two sub deposits according to different fluid sources and formation conditions: (1) a deep but cooler hydrothermal Kratz Spring South deposit with a juvenile fluid source and (2) a shallow but hotter magmatic-hydrothermal Kratz Spring North deposit with variable fluid sources. Our genetic model suggests the two Kratz Spring deposits are local expressions of the same mineralization system, i.e., the Kratz Spring South deposit is a distal, lower-temperature offshoot of the feeder system that formed the Kratz Spring North deposit. Understanding the magmatic-hydrothermal plumbing system that formed Missouri\u27s IOA-IOCG deposits is important to guiding critical mineral exploration efforts in the region

Cenozoic volcanism of the Capel-Faust Basins, Lord Howe Rise, SW Pacific Ocean

New bathymetry, geophysical data and samples were acquired in 2007 during a marine reconnaissance survey using the R.V. Tangaroa in the frontier Capel and Faust basins, Lord Howe Rise (LHR) by Geoscience Australia as part of the Australian Government's Offshore Energy Security Program. This survey identified a number of volcanic features including cones, flows and sill-related features on the seafloor. Based on analysis of seismic data and swath bathymetry, there are at least two distinct ages of volcanism exposed on the seafloor; Late Miocene-Pliocene cones with a largely unmodified conical shape and Eocene-Oligocene volcanic features. The Middle Miocene Gifford Guyot, part of the Lord Howe seamount chain was included in the survey area. Volcanic features are common on the seafloor of the LHR and in the neighbouring Tasman Basin, with two identified north-south seamount hotspot chains to the west of the Capel-Faust region that have been active from the Miocene to recent. The previously completed ZoNeacute;Co 5 swath-mapping, seismic and sampling survey also identified a few small conical seamounts on the northern LHR, along a roughly north-northwest trend, dated as Early Miocene. The younger Capel-Faust seamounts are aligned with these and the age relationships suggest they could be part of a single seamount chain. The older cones do not show any preferred alignment within the survey area and are too old to be related to the current hotspot activity in the region. Samples are variably altered but trace element abundances of all dredged mafic rocks indicate they are alkalic basalt. Samples from the younger cones can be differentiated from each other and from the Gifford Guyot on a plot of Ti, Sr and Tb/Yb reflecting different source depths or degrees of partial melting. A comparison of pyroxene from the older more altered cones and the younger cones shows that these most likely represent two distinct magmatic events and that the younger cones are similar to the ZoNéCo 5 seamounts.11 page(s

National Energy and Climate Plans: Importance of Synergy

In the modern world, including the European Union, the Baltic States and Latvia, the power industry has a broad definition, area and content, several social life and economic existence, comfort and safety provision. It also covers the following segments: heat/thermal energy, transport/fuel, electricity, energy resources and their types, etc

Mass transfer of fluids and metals in the deep Earth

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On the formation of magmatic sulfide systems in the lower crust by long‐lived mass transfer through the lithosphere: Insights from the Valmaggia pipe, Ivrea Verbano Zone, Italy

The lower crustal domain of the Ivrea\u2010Verbano Zone (NW Italy) hosts five ~300\u2010m\u2010wide pipe\u2010like ultramafic intrusions that are metasomatized and exhibit Ni\u2010Cu\u2010PGE sulfide mineralization. To better constrain the role of metasomatism in the ore genesis, we studied the best\u2010preserved pipe at Valmaggia which was emplaced 249 Myrs ago. Phlogopite 40Ar/39Ar analyses show that the pipe was infiltrated by metasomatic fluids derived from the subcontinental lithospheric mantle (SCLM) in two pulses at ~208 Ma and ~189 Ma which introduced sulfides into the pipe. Consequently, the pipe repeatedly acted as a preferred path for mass transfer from the SCLM into the lower crust over >60 Myrs (i.e., emplacement to second metasomatic pulse). Uplifted block margins, such as the Ivrea\u2010Verbano Zone, are potentially important exploration targets for magmatic sulfides. We argue that exploration strategies should focus on structures such as pipes that can focus metasomatic agents during ascent through the lithosphere

Early Global Mantle Chemical and Isotope Heterogeneity Revealed by the Komatiite-Basalt Record: The Western Australia Connection

Although the heterogeneous nature of the chemical composition of Earth\u27s mantle is now well established, the origin and longevity of the heterogeneities continue to be debated. In order to further study early-Earth heterogeneities, we present a set of Sm-Nd, Lu-Hf, Re-Os, and Hf-W isotope and lithophile and siderophile element abundance data for komatiites and basalts from the ∼3.53 Ga Coonterunah, ∼3.34 Ga Kelly, and ∼3.18 Ga Ruth Well and Regal systems of the Pilbara Craton in Western Australia. The Sm-Nd, Lu-Hf, and Re-Os isotope data yield isochrons consistent with the accepted emplacement ages of the respective komatiite-basalt lavas. The mantle sources evolved with long-term 147Sm/144Nd = 0.200 to 0.214 and 176Lu/177Hf = 0.0355 to 0.0395, spanning the entire range of the time-integrated Sm/Nd and Lu/Hf measured in the Archean and Proterozoic komatiite-basalt systems to-date. Unlike with the other early Archean komatiites and basalts, the coupled 143Nd-176Hf isotope systematics of the Pilbara lavas provide no evidence for the involvement of early magma ocean processes in the evolution of their mantle sources. Episodes of variable degrees of partial mantle melting and melt extraction can account for the observed large variations in the time-integrated Sm/Nd and Lu/Hf ratios in the early Archean mantle domains. In contrast to the highly variable Nd-Hf systematics, the initial γ187Os values vary within a narrow range from +0.9 to -0.4 indicating that the Pilbara mantle sources evolved with chondritic time-integrated Re/Os. The apparent discrepancy between the depletions in incompatible lithophile trace elements and near-chondritic Re/Os observed globally is reconciled via a model whereby early low-degree mantle melting events fractionated Sm from Nd and Lu from Hf, but had little effect on the Re/Os ratio. This in turn would imply early formation and long-term isolation of a basaltic crust highly enriched in incompatible lithophile trace elements. The calculated total HSE abundances in the komatiite mantle sources range from ∼30% in the Coonterunah to ∼70% in the Regal system, of those in the estimates for the modern BSE, indicative of a 2.4x increase in HSE abundances from 3.53 to 3.18 Ga. All four komatiite-basalt systems exhibit positive 182W anomalies ranging between +11.4 and +7.7 ppm. The 182W/184W compositions and calculated HSE abundances in the Pilbara komatiite-basalt sources are inversely correlated and are most consistent with grainy late accretion of large differentiated planetesimals. Regression of the combined 182W-HSE data for the komatiite systems allows an estimate of the W isotopic composition of the pre-late accretion BSE of +17 ± 7. This estimate is similar to that of the Moon of +25 ± 5 and lends further support to the notion regarding an initially common W isotopic composition in the Earth-Moon system. Regression of the available HSE abundance data for komatiite mantle sources worldwide provides an estimate for the time of complete homogenization of late accreted materials within the mantle by 2.5 ± 0.2 Ga. Calculations indicate an average survival time of late accreted planetesimals in the Earth\u27s mantle of 1.9 ± 0.2 Ga, which constrains the average mantle stirring rates for the HSE in the Hadean and Archean

A metasomatized lithospheric mantle control on the metallogenic signature of post-subduction magmatism

Ore deposits are loci on Earth where energy and mass flux are greatly enhanced and focussed, acting as magnifying lenses into metal transport, fractionation and concentration mechanisms through the lithosphere. Here we show that the metallogenic architecture of the lithosphere is illuminated by the geochemical signatures of metasomatised mantle rocks and post-subduction magmatic-hydrothermal mineral systems. Our data reveal that anomalously gold and tellurium rich magmatic sulfides in mantle-derived magmas emplaced in the lower crust share a common metallogenic signature with upper crustal porphyry-epithermal ore systems. We propose that a trans-lithospheric continuum exists whereby post-subduction magmas transporting metal-rich sulfide cargoes play a fundamental role in fluxing metals into the crust from metasomatised lithospheric mantle. Therefore, ore deposits are not merely associated with isolated zones where serendipitous happenstance has produced mineralisation. Rather, they are depositional points along the mantle-to-upper crust pathway of magmas and hydrothermal fluids, synthesising the concentrated metallogenic budget available

LA-ICP-MS analysis on chromite : a guide for the geodynamic setting of formation of ultramafic massifs in the Bulgarian Rhodopes

Chromite is a well-established indicator for the petrogenesis and geodynamic setting of ultramafic rocks. However, despite of its higher resistance to alteration relative to other minerals, its chemistry and structure can be substantially affected by secondary processes (i.e., sub-solidus re-equilibrium, metamorphism or hydrothermal alteration). The effects of these processes are minimized in chromite forming monomineralic bodies (i.e., chromitites). In the Dobromir tsi Ultramafic Massif (Central Rhodope, southern Bulgaria) chromitite bodies of uncer tain origin occur within highly metamorphosed harzburgite-dunite. Metamorphic alteration modified original chemistry and structure of almost chromite grains, although few core relics of chromite from the more massive part of the bodies preserved those pristine compositions. LA-ICP-MS analysis reveals cores characterized by high Cr0.67-0.74) with Ti =1280-1641 ppm, Mn =1,267-1,400 ppm, Ni = 835-1,011 ppm, V =672-723 ppm, Zn =428-456 ppm, Co =224-244 ppm, Ga =30-35 ppm, and Sc = 3-6 ppm, and cores with lower Cr0.55-057) characterized by higher Ti (2041-2555 ppm), Mn (1575-1747 ppm), V (792-840 ppm), Zn (522-569 ppm) and Ga (47-49 ppm), slightly lower Ni (858-957 ppm) but similar Co (220-238 ppm) and Sc (3 ppm). These minor and trace element compositions of chromite of the Dobromir tsi chromitites are in accordance with that for podiform chromitites hosted in the mantle section of ophiolites originated in supra-subduction zone settings. Their compositions definitively differ from layered chromitites of mafic continental intrusions or komatiites.1 page(s