Magnetic susceptibility of Middle Ordovician sedimentary rocks, Pakri Peninsula, NW Estonia

Magnetic susceptibility (MS), its frequency-dependence and anisotropy of the Middle Ordovician Dapingian and Darriwilian sedimentary sequence from three sites (Uuga, Testepere and Leetse) in the Pakri Peninsula, NW Estonia are analysed in combination with the mineralogical composition. The study is based on 463 cores drilled at intervals of a few centimetres to a maximum of about 1 m. All the samples show low and positive MS, which suggests the presence of small quantities of paraand/or ferromagnetic minerals. The stratigraphic units of the three studied sites have a similar along-section appearance, which provides a base for a composite curve. The relatively higher susceptibilities are carried by secondary Fe-Ti oxides (Toila Formation), goethite ooids (Kandle Formation) and ferrous dolomite (Pae Member), whereas paramagnetic minerals are mostly responsible for the rest of the sequence. Considering the dependence of MS on regressive transgressive cycles (high/low MS within deposits of regressive/transgressive parts of the cycles, respectively), the MS data do not agree with sedimentologically derived sea-level compilations. The measured changes in MS in the Pakri Peninsula outcrops correlate at certain characteristic levels with those deposited in the deeper part of the palaeobasin (Viki core), indicating that the post-depositional iron mobilization within the sediments took place at least at a regional level. Because of post-depositional reorganization of ferromagnetic carrier minerals, the MS values may, however, not be used as a detrital proxy.Peer reviewe

Zircon at the nanoscale records metasomatic processes leading to large magmatic-hydrothermal ore systems

The petrography and geochemistry of zircon offers an exciting opportunity to better understand the genesis of, as well as identify pathfinders for, large magmatic–hydrothermal ore systems. Electron probe microanalysis, laser ablation inductively coupled plasma mass spectrometry, high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) imaging, and energy-dispersive X-ray spectrometry STEM mapping/spot analysis were combined to characterize Proterozoic granitic zircon in the eastern Gawler Craton, South Australia. Granites from the ~1.85 Ga Donington Suite and ~1.6 Ga Hiltaba Suite were selected from locations that are either mineralized or not, with the same style of iron-oxide copper gold (IOCG) mineralization. Although Donington Suite granites are host to mineralization in several prospects, only Hiltaba Suite granites are considered “fertile” in that their emplacement at ~1.6 Ga is associated with generation of one of the best metal-endowed IOCG provinces on Earth. Crystal oscillatory zoning with respect to non-formula elements, notably Fe and Cl, are textural and chemical features preserved in zircon, with no evidence for U or Pb accumulation relating to amorphization effects. Bands with Fe and Ca show mottling with respect to chloro–hydroxy–zircon nanoprecipitates. Lattice defects occur along fractures crosscutting such nanoprecipitates indicating fluid infiltration post-mottling. Lattice stretching and screw dislocations leading to expansion of the zircon structure are the only nanoscale structures attributable to self-induced irradiation damage. These features increase in abundance in zircons from granites hosting IOCG mineralization, including from the world-class Olympic Dam Cu–U–Au–Ag deposit. The nano- to micron-scale features documented reflect interaction between magmatic zircon and corrosive Fe–Cl-bearing fluids in an initial metasomatic event that follows magmatic crystallization and immediately precedes deposition of IOCG mineralization. Quantification of α-decay damage that could relate zircon alteration to the first percolation point in zircon gives ~100 Ma, a time interval that cannot be reconciled with the 2–4 Ma period between magmatic crystallization and onset of hydrothermal fluid flow. Crystal oscillatory zoning and nanoprecipitate mottling in zircon intensify with proximity to mineralization and represent a potential pathfinder to locate fertile granites associated with Cu–Au mineralization.Liam Courtney-Davies, Cristiana L. Ciobanu, Max R. Verdugo-Ihl, Ashley Slattery, Nigel J. Cook, Marija Dmitrijeva, William Keyser, Benjamin P. Wade, Urs I. Domnick, Kathy Ehrig, Jing Xu, and Alkiviadis Kontonikas-Charo

Technical and vocational education and training (TVET) for young people in low- and middle-income countries: a systematic review and meta-analysis

The world is facing a worsening youth employment crisis. In response, technical and vocational education and training (TVET) is back on the development agenda after years of neglect. This systematic review examined the evidence from studies evaluating the impacts of TVET interventions for young people in low- and middle-income countries (LMICs). The 26 included studies evaluated 20 different interventions, predominantly from Latin America. Meta-analyses of the effectiveness of TVET on five outcome measure categories were conducted. The overall mean effects on overall paid employment, formal employment, and monthly earnings were small, positive, and significant; however, significant heterogeneity was observed. Moderator analysis was performed in an attempt to explain between-study differences in effects. The overall paucity of research in this area, together with specific gaps and methodological limitations, affirm the need for strengthening the evidence base. Implications for policy, practice and research are discussed

Mineralization-alteration footprints in the Olympic Dam IOCG district, South Australia: The Acropolis prospect

The Acropolis prospect, 20 km southwest from the Olympic Dam Cu-U-Au-Ag deposit, South Australia, is a vein-style magnetite (±apatite ±hematite) system. A whole-rock dataset comprising 4864 core samples from 14 drillholes was analysed using multivariate statistical analyses to understand and identify geochemical signatures of mineralization, as well as the expressions and extents of hydrothermal alteration. Statistical analysis included unsupervised (principal component analysis, hierarchical and k-means clustering) and supervised (random forests) machine learning algorithms. The geology of the Acropolis prospect is presented as a 3D geological model complemented by cross-sections. The results of statistical analyses are overlaid and interpreted relative to the geological model, and encompass a projection of sodic and propylitic alteration as PC3, and mineralization signature as PC1. Although the mineralization footprint of the Acropolis prospect partially overlaps with a Hiltaba Suite granite, it is not centred on the granite body. A distinct ‘magnetite’ signature of Fe-V-Ni-Co is developed in the southwestern part of Acropolis and represents samples containing >60 wt% Fe. In contrast, the ‘hematite’ signature displays an association of REE, W, Sn, Sb, U, Th, Ca and P, and is present throughout the Acropolis prospect with the exception of drillhole ACD5, which is non-mineralized. Interpolated values of Cu (> 200 ppm) indicate an offset from Fe-rich veins, thus supporting a genetic model in which Cu-bearing mineralization overprints Cu-Au-deficient magnetite-dominant veins. The results obtained provide insights into the evolution from magnetite to hematite-dominant IOCG systems and may provide a proxy for exploration of shallow and economically significant IOCG deposits in the eastern Gawler Craton.Marija Dmitrijeva, Cristiana L. Ciobanu, Kathy J. Ehrig, Nigel J. Cook, Andrew V. Metcalfe, Max R. Verdugo-Ihl, Jocelyn McPhi

Geochemical Data Analysis of Iron Oxide Copper-Gold Mineralization, Wirrda Well Prospect, South Australia

Multivariate statistical analysis encompasses a range of methods that can fingerprint mineralization, alteration, and host-rock signatures within an ore system, thus assisting in interpretation of ore deposit models and supporting exploration programs. We utilize numeric interpolation of metals (Fe, Cu, and U), principal component analysis (PCA), and a Random Forest (RF) classification, applied to whole-rock geochemical data, to define metal distribution patterns and geochemical signatures of alteration/Fe oxide mineralization in the Wirrda Well iron oxide copper-gold (IOCG) prospect. The prospect is located in the Olympic Dam district, Gawler Craton (South Australia), bounded by NW- and NE-trending faults and characterized by two distinct residual gravity anomalies: Wirrda Well North (WW-North) and Wirrda Well South (WW-South). The mineralization is attributed to hydrothermal activity associated with magmatism at -1.6 Ga that generated the Gawler Silicic Large Igneous Province (SLIP), corroborated by U-Pb dates of hematite. The mineralization is hosted by the -1.85 Ga Donington Granitoid Suite and abundant mafic dikes, the majority of which are considered to predate mineralization. Five lithogeochemical clusters are defined from PCA, hierarchical, and k-means clustering, efficiently discriminating least-altered felsic lithologies from altered, mixed lithologies (felsic and mafic) and, importantly, two distinct mineralization clusters, representing magnetite and hematite. The RF method is successfully applied to a larger data set with a smaller number of analyzed elements to extrapolate the results over the whole prospect. WW-North is characterized by an Fe-V-Ni-Co signature defined as "magnetite-type," whereas WW-South contains higher-grade Cu-Au(+/- Bi-Ag) mineralization and has a marked Mo-W-U(+/- Sn) signature defined as "hematite-type." The latter is considered a characteristic hypogene hydrothermal signature in the Olympic Dam District. Sodic and hydrolytic alteration are associated with Fe metasomatism and are depicted by the magnetite and hematite clusters, respectively. In combination, the results indicate that premineralization mafic dikes provided permeable structures for fluid focusing and metal deposition, since metals are concentrated by their contacts with host granite, specifically in WW-North. The metal interpolations and geochemical data analysis suggest strong lithological-structural control on IOCG mineralization at Wirrda Well.Dmitrijeva, M (Dmitrijeva, Marija), Ciobanu, CL (Ciobanu, Cristiana L.), Ehrig, K (Ehrig, Kathy), Cook, NJ (Cook, Nigel J.), Verdugo-Ihl, MR (Verdugo-Ihl, Max R.), Metcalfe, AV (Metcalfe, Andrew, V), Kamenetsky, VS (Kamenetsky, Vadim S.), McPhie, J (McPhie, Jocelyn), Carew, M (Carew, Mick)

In situ apatite and carbonate Lu-Hf and molybdenite Re-Os geochronology for ore deposit research: Method validation and example application to Cu-Au mineralisation

Available online 15 May 2024The development of laser ablation inductively coupled plasma quadrupole tandem mass spectrometry (LA-ICP-Q-MS/MS) opens new opportunities to rapidly date a variety of hydrothermal minerals. Here we present in situ Lu-Hf and Re-Os dates for hydrothermal apatite and molybdenite, respectively. We further report the first in situ Lu-Hf dates for bastnäsite, dolomite, and siderite, and assess their potential for constraining ore deposit geochronology. For method validation, we report isotope-dilution Lu-Hf dates for apatite reference material Bamble-1 (1102 ± 5 Ma) and calcite reference material ME-1 (1531 ± 7 Ma), enabling improved accuracy on matrix-matched calibration for LA-ICP-MS/MS Lu-Hf dating. The new methods are applied to the Vulcan Iron-Oxide Copper-Gold (IOCG) prospect in the Olympic Cu-Au Province of South Australia. Such deposits have been difficult to accurately date, given the general lack of reliable mineral geochronometers that are cogenetic with IOCG mineralisation. Hydrothermal apatite Lu-Hf dates and molybdenite Re-Os dates demonstrate that mineralisation at Vulcan largely occurred at ca. 1.6 Ga, contemporaneous with the world class Olympic Dam deposit. Our data also indicates that the Lu-Hf system in apatite is more robust than the U-Pb system for determining the timing of primary apatite formation in an IOCG system. We further demonstrate that dolomite can retain Lu-Hf growth ages over an extended time period (>1.5 billion years), providing constraints on the timing of primary ore mineral crystallisation during brecciation and IOCG mineralisation. Finally, late Neoproterozoic (ca. 589–544 Ma) and Carboniferous (ca. 334 ± 7 Ma) Lu-Hf dates were obtained for texturally late Cubearing carbonate veins, illustrating that the carbonate Lu-Hf method allows direct dating of Cu remobilisation events. This has important implications for mineral exploration as the remobilised Cu may have been transferred to younger deposits hosted in Neoproterozoic sedimentary basins overlaying the Olympic IOCG province.Alexander Simpson, Stijn Glorie, Martin Hand, Sarah E. Gilbert, Carl Spandler, Marija Dmitrijeva, Greg Swain, Angus Nixon, Jacob Mulder, Carsten Münke

Micron- to nanoscale characterisation and U-Pb geochronology of zircon from granites of the Samphire Pluton, South Australia

Zircons from three distinct granites within the Samphire Pluton, South Australia, are characterised at the micron- to nanoscale. Sensitive high-resolution ion microprobe (SHRIMP) U-Pb zircon dating generated ²⁰⁷Pb/²⁰⁶Pb weighted average ages of 1586 ± 9.3 Ma, 1583.2 ± 8.5 Ma and 1578 ± 9.5 Ma, respectively. Although zircons from all three granites display evidence of hydrothermal overprinting, this is most strongly expressed in a distinct, red-colored granite referred to here as Granite C. Alteration is expressed as variation in the concentrations of HREE + Y, Th and Pb, whereby grain margins are relatively enriched in these elements and both Zr and Si are depleted. Altered zircon cores have high U contents relative to grain margins, which are appreciably poorer in this element, whereas Th is strongly enriched within crosscutting microfractures. Coupled with the relative enrichment in non-formula elements and marked disturbance of U-Th-Pb isotope ratios, the nanoscale observations of Pb-bearing nanoparticles (galena?) implying mobility of Pb and other elements, nanofractures and structural defects demonstrate that zircon in Granite C has undergone multi-stage alteration impacting upon accurate dating. Importantly, and with implications for analogous systems elsewhere, our results confirm nanoscale open system U-Pb behaviour in Hiltaba Suite zircon. SHRIMP U-Pb zircon geochronology cannot confidently resolve any statistical differences in the age of the three granites, despite their distinct appearance suggesting they might represent temporally distinct phases of a larger magmatic system. Zircons within the most altered Granite (C), directly underlying the Blackbush uranium prospect contain convincing micron- to nanoscale evidence for an alteration event that triggered a remobilisation of uranium from granite into the cover sequence.Urs Domnick, Nigel J. Cook, Cristiana L. Ciobanu, Liam Courtney-Davies, Marija Dmitrijeva, Max R. Verdugo-Ihl, Jing Xu, William Keyser, Ashley Slattery, Allen K. Kennedy, Russel Bluc

Fiziologinio afekto būsenos reikšmė nužudymui ir sunkiam sveikatos sutrikdymui kvalifikuoti

Lietuvos ir visų demokratinių valstybių teisėje žmogaus gyvybė bei jo sveikata yra laikomos svarbiausiomis vertybėmis, kurios unikalios tuo, kad yra visų kitų žmogaus vertybių sąlyga ir pagrindas. Žmogaus gyvybė ir sveikatos apsauga gali būti užtikrinama priimant įvairių teisės šakų normas, taip pat nustatant baudžiamąją atsakomybę už kėsinimąsi į žmogaus gyvybę ir sveikatą. Lietuvos Respublikos baudžiamajame kodekse (toliau – BK) atsakomybė už paprastą ir kvalifikuotą nužudymą numatyta 129 straipsnyje, o už sunkų sveikatos sutrikdymą - 135 straipsnyje. Be to, šios nusikalstamos veikos gali būti padaromos kaltininkui esant riboto pakaltinamumo būsenoje (fiziologinis afektas), todėl įstatymų leidėjas tokias veikas laiko privilegijuotomis ir įtvirtina atsakomybę už nužudymą ir sunkų sveikatos sutrikdymą labai susijaudinus atskirose kodekso normose (BK 130 str. ir 136 str.). Nužudymo ir sunkaus sveikatos sutrikdymo afekto būsenoje kvalifikavimo ir atribojimo klausimai yra pakankamai sudėtingi praktiniu aspektu ne tik teisininkams, bet ir teismo psichiatrams, nes dažniausiai tiriamojo asmens psichikos būsena nusikalstamos veikos metu yra ištiriama žymiai vėliau, t. y. ekspertai turi duoti išvadą apie tiriamojo subjekto psichikos būseną praeityje. Šio tiriamojo darbo metu atlikta 20 baudžiamųjų bylų medžiagos analizė leidžia padaryti išvadą, jog tik pavieniais atvejais konstatuojama, kad kaltininkas padarė nužudymą ar sunkų sveikatos sutrikdymą fiziologinio afekto sukeltoje būsenoje. Dažniausiai analizuojamas nusikalstamas veikas padaro pakaltinami subjektai, o žymiai rečiau – psichikos ligoniai, t. y. nepakaltinami asmenys. Raktažodžiai: nužudymas, sunkus sveikatos sutrikdymas, neteisėtas ar itin įžeidžiantis nukentėjusiojo asmens poelgis, patologinis ir fiziologinis afektas, teismo psichiatrinė ekspertizė.Based on the laws of Lithuania and all democratic states, human life and health are considered as the most important values as well as a unique condition and basis of all other human values. Protection of human life and health may be ensured by establishing standards of various legal fields as well as determining criminal liability for encroachment on human life and health. The Criminal Code of the Republic of Lithuania (hereinafter referred to as the CC) determines liability for a simple or qualified homicide in Article 129, whereas grievous bodily injury is covered in Article 135. Moreover, the aforementioned criminal acts may be committed when the perpetrator is in the state of diminished responsibility (physiological affect), therefore the legislator considers such acts to be exclusive and establishes liability for homicide and grievous bodily injury in a highly agitated state in different regulations of the Code (Art. 130 and Art. 136 of the CC). The issues of qualification and dissociation of homicide and grievous bodily injury in the state of affect are rather complicated in terms of the practical aspect there of not only for lawyers but for forensic psychiatrists as well because usually the mental state of the subject at the time of the crime is examined much later, i.e. the experts must provide conclusions about the mental state of the subject in the past. Analysis of the material of 20 criminal cases done within the course of this research paper enables to draw a conclusion that there are only individual cases stating that the perpetrator committed a homicide and grievous bodily injury in a state caused by a physiological affect. The criminal acts under analysis are mostly committed by mentally sane individuals, whereas mental patients, i.e. insane people, get involved in them significantly less frequently. Key words: homicide, grievous bodily injury, illegal or highly offensive action of the victim, pathological and physiological affect, forensic psychiatric examination