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Chemical and lead isotope analyses aided by metallographic examination of copper axes found at the Late Neolithic settlement of Kietrz in southwestern Poland provide new evidence for the origin of copper and metal trade routes in the region. Our results indicate that metal used for the axes could be sourced from copper mines in modern Slovakia, Bulgaria and perhaps Serbia. The evidence from this study confirms that the Funnel Beaker people from Poland became parties to a metal trading network that connected much of continental Europe in the mid‐4th millennium bce and provides a better understanding of how these contacts provided the background for the technological and socio‐economic developments of the Baden era. [ABSTRACT FROM AUTHOR]

We present the first national-scale lead (Pb) isotope maps of Australia based on surface regolith for five isotope ratios, 206Pb/204Pb , 207Pb/204Pb , 208Pb/204Pb , 207Pb/206Pb , and 208Pb/206Pb , determined by single-collector sector field inductively coupled plasma mass spectrometry after an ammonium acetate leach followed by aqua regia digestion. The dataset is underpinned principally by the National Geochemical Survey of Australia (NGSA) archived floodplain sediment samples. We analysed 1219 samples (0–10 cm depth, <2 mm grain size), collected near the outlet of 1119 large catchments covering 5.647×106 km 2 (∼75% of Australia). The samples consist of mixtures of the dominant soils and rocks weathering in their respective catchments (and possibly those upstream) and are therefore assumed to form a reasonable representation of the average isotopic signature of those catchments. This assumption was tested in one of the NGSA catchments, within which 12 similar samples were also taken; results show that the Pb isotope ratios of the NGSA catchment outlet sediment sample are close to the average of the 12 upstream sub-catchment samples. National minimum, median, and maximum values were 15.56, 18.84, and 30.64 for 206Pb/204Pb ; 14.36, 15.69, and 18.01 for 207Pb/204Pb ; 33.56, 38.99, and 48.87 for 208Pb/204Pb ; 0.5880, 0.8318, and 0.9847 for 207Pb/206Pb ; and 1.4149, 2.0665, and 2.3002 for 208Pb/206Pb , respectively. The new dataset was compared with published bedrock and ore Pb isotope data, and it was found to dependably represent crustal elements of various ages from Archaean to Phanerozoic. This suggests that floodplain sediment samples are a suitable proxy for basement and basin geology at this scale, despite various degrees of transport, mixing, and weathering experienced in the regolith environment, locally over protracted periods of time. An example of atmospheric Pb contamination around Port Pirie, South Australia, where a Pb smelter has operated since the 1890s, is shown to illustrate potential environmental applications of this new dataset. Other applications may include elucidating details of Australian crustal evolution and mineralisation-related investigations. The new regolith Pb isotope dataset for Australia is publicly available (Desem et al., 2023; 10.26186/5ea8f6fd3de64). [ABSTRACT FROM AUTHOR]

The widely accepted paradigm of Earth's geochemical evolution states that the successive extraction of melts from the mantle over the past 4.5 billion years formed the continental crust, and produced at least one complementary melt-depleted reservoir that is now recognized as the upper-mantle source of mid-ocean-ridge basalts.sup.1. However, geochemical modelling and the occurrence of high .sup.3He/.sup.4He (that is, primordial) signatures in some volcanic rocks suggest that volumes of relatively undifferentiated mantle may reside in deeper, isolated regions.sup.2. Some basalts from large igneous provinces may provide temporally restricted glimpses of the most primitive parts of the mantle.sup.3,4, but key questions regarding the longevity of such sources on planetary timescales--and whether any survive today--remain unresolved. Kimberlites, small-volume volcanic rocks that are the source of most diamonds, offer rare insights into aspects of the composition of the Earth's deep mantle. The radiogenic isotope ratios of kimberlites of different ages enable us to map the evolution of this domain through time. Here we show that globally distributed kimberlites originate from a single homogeneous reservoir with an isotopic composition that is indicative of a uniform and pristine mantle source, which evolved in isolation over at least 2.5 billion years of Earth history--to our knowledge, the only such reservoir that has been identified to date. Around 200 million years ago, extensive volumes of the same source were perturbed, probably as a result of contamination by exogenic material. The distribution of affected kimberlites suggests that this event may be related to subduction along the margin of the Pangaea supercontinent. These results reveal a long-lived and globally extensive mantle reservoir that underwent subsequent disruption, possibly heralding a marked change to large-scale mantle-mixing regimes. These processes may explain why uncontaminated primordial mantle is so difficult to identify in recent mantle-derived melts. Globally distributed kimberlites have their origins in a single, homogeneous early Earth reservoir that was subsequently perturbed, probably by subduction along the margins of Pangaea, around 200 million years ago., Author(s): Jon Woodhead [sup.1] , Janet Hergt [sup.1] , Andrea Giuliani [sup.1] [sup.2] [sup.5] , Roland Maas [sup.1] , David Phillips [sup.1] , D. Graham Pearson [sup.3] , Geoff Nowell [...]

The paper explores the perceptions and management practices regarding parental leave among a specific group of employers: those likely to have low parental leave take-up among staff. We conducted qualitative interviews with employers in 18 Luxembourg-based companies of sizes and economy sectors where low take-up is most prevalent. We explored how leave requests, employees' absences and their return after parental leave are managed and how employers deal with the recent reform of parental leave policy. The results show that employers try to minimize the cost of fathers' absence from work by negotiating over the timing of take-up and the form of leave to be taken. Parental leave is preferred over other work–life balance measures because it is perceived as a short-term and timely arrangement during a career. In this particular group of employers, parental leave is also viewed as more compatible with work and organization processes than other measures. [ABSTRACT FROM AUTHOR]

We present the first national-scale lead (Pb) isotope maps of Australia based on surface regolith for five isotope ratios, 206Pb/204Pb, 207Pb/204Pb, 208Pb/204Pb, 207Pb/206Pb, and 208Pb/206Pb, determined by single collector Sector Field-Inductively Coupled Plasma-Mass Spectrometry after an Ammonium Acetate leach followed by Aqua Regia digestion. The dataset is underpinned principally by the National Geochemical Survey of Australia (NGSA) archived floodplain sediment samples. We analysed 1219 'top coarse' (0-10 cm depth, <2 mm grain size) samples, collected near the outlet of 1119 large catchments covering 5.647 million km2 (~75% of Australia). The samples consist of mixtures of the dominant soils and rocks weathering in their respective catchments (and possibly those upstream) and are therefore assumed to form a reasonable representation of the average isotopic signature of those catchments. This assumption was tested in one of the NGSA catchments, within which 12 similar 'top coarse' samples were also taken; results show that the Pb isotope ratios of the NGSA catchment outlet sediment sample are close to the average of the 12 sub-catchment, upstream samples. National minimum, median and maximum values reported for 206Pb/204Pb were 15.558, 18.844, 30.635; for 207Pb/204Pb 14.358, 15.687, 18.012; for 208Pb/204Pb 33.558, 38.989, 48.873; for 207Pb/206Pb 0.5880, 0.8318, 0.9847; and for 208Pb/206Pb 1.4149, 2.0665, 2.3002, respectively. The new dataset was compared with published bedrock and ore Pb isotope data, and was found to dependably represent crustal elements of various ages from Archean to Phanerozoic. This suggests that floodplain sediment samples are a suitable proxy for basement and basin geology at this scale, despite various degrees of transport, mixing, and weathering experienced in the regolith environment, locally over protracted periods of time. An example of atmospheric Pb contamination around Port Pirie, South Australia, where a Pb smelter has operated since the 1890s, is shown to illustrate potential environmental applications of this new dataset. Other applications may include elucidating detail of Australian crustal evolution and mineralisation-related investigations. The new regolith Pb isotope dataset for Australia is publicly available (Desem et al., 2023; http://dx.doi.org/10.26186/5ea8f6fd3de64). [ABSTRACT FROM AUTHOR]

Analysis of otolith strontium isotope ratios ([sup.87]Sr/[sup.86]Sr) is an increasingly utilized approach for studying fish migration. We analysed surface and ground water from the Daly River catchment in the wet-dry tropics of northern Australia over 2 years. Analyses of otolith [sup.87]Sr/[sup.86] Sr ratios were also conducted for freshwater sooty grunter (Hephaestus fuliginosus) and the putatively diadromous diamond mullet (Liza ordensis). Spatial variation in freshwater[sup.87]Sr/[sup.86] Sr was high (range: 0.71612-0.78059), and there was strong seasonality in water [sup.87]Sr/[sup.86]Sr, with highest values in the wet season. Temporal variation in water [sup.87]Sr/[sup.86]Sr ratios is attributed to seasonal patterns in surface runoff from geological formations with radiogenic compositions versus input from groundwater aquifers interacting with less radiogenic formations. Temporal variation in water [sup.87]Sr/[sup.86]Sr ratios precluded robust inference on movement within fresh water for both species, although movement across salinity gradients by diamond mullet was clearly identified. We conclude that temporally and spatially replicated water Sr data should be a general requisite for studies that analyse otolith Sr ([sup.87]Sr/[sup.86]Sr, Sr/Ca, Sr/Ba) to make inferences about fish movement and migration. L'analyse des rapports isotopiques [sup.87]Sr/[sup.86] Sr des otolithes est une approche de plus en plus utilisee pour etudier la migration des poissons. Nous avons analyse de l'eau souterraine et de surface dans le bassin versant de la riviere Daly dans la region tropicale humide/seche d'Australie meridionale sur une periode de 2 ans. Des analyses des rapports [sup.87]Sr/[sup.86]Sr d'otolithes ont egalement ete realisees pour Hephaestus fuliginosus, un poisson d'eau douce, et Liza ordensis, presume etre diadrome. L'eau douce presentait de fortes variations du [sup.87]Sr/[sup.86] Sr dans l'espace (fourchette : 0,71612-0,78059), et la saisonnalite du [sup.87] Sr/[sup.86] Sr de l'eau etait marquee, les valeurs les plus elevees caracterisant la saison humide. Les variations dans le temps des rapports [sup.87]Sr/[sup.86] Sr de l'eau sont attribuees a des motifs saisonniers des apports relatifs d'eau de ruissellement issue de formations geologiques radiogeniques et d'eau souterraine interagissant avec des formations moins radiogeniques. Les variations temporelles de[sup.87]Sr/[sup.86]Sr empechent toute inference robuste concernant les deplacements en eau douce pour les deux especes, bien que des deplacements de Liza ordensis le long de gradients de salinite aient ete clairement discernes. Nous en concluons que des donnees surle Srde l'eau reproduites dans le temps et dans l'espace devraient constituerun element necessaire des etudes du Sr ([sup.87]Sr/[sup.86] Sr, Sr/Ca, Sr/Ba) d'otolithes ayant pour but de faire des inferences sur les deplacements et la migration des poissons. [Traduit par la Redaction], Introduction Movement and migration by fishes is an important process in many riverine ecosystems, creating ecological connections between spatially distant habitats and functioning as a conduit for the transport of [...]

'Transitional kimberlite' is a collective term previously used to classify rocks occurring in southern Africa that show bulk rock geochemical and Sr–Nd isotope features intermediate between (cratonic) lamproites and kimberlites. However, it is now well established that detailed petrographic and mineral chemical criteria represent a more robust approach towards the classification of kimberlites, lamproites and related rocks. Here, we re-assess the classification of southern African 'transitional kimberlites' by combining new petrographic observations and mineral compositional results for samples from six localities (Leicester, Frank Smith, Wimbledon, Melton Wold, Droogfontein, and Silvery Home) straddling the southwestern margin of the Kaapvaal Craton. These new data indicate that Leicester and Frank Smith are archetypal kimberlites, whereas Wimbledon, Melton Wold, Droogfontein, and Silvery Home represent bona fide olivine lamproites. We combine the mineral chemical results with new (Wimbledon) and existing bulk rock trace element and Nd–Hf isotope compositions, and emplacement ages, to assess whether the previously documented trends in Nd–Hf isotope vs time for these 'transitional kimberlites' constrain their petrological evolution. Modal groundmass mineralogy, bulk rock K/La and chromite compositions, the latter being a proxy for primitive melt composition, are linearly correlated with emplacement age and initial Nd–Hf isotope compositions. These observations suggest derivation of both older lamproites (181–115 Ma) and younger kimberlites (114–93 Ma), from a common evolving source. The temporal evolution of Nd–Hf isotope compositions in these rocks converge to values typical of archetypal Cretaceous kimberlites elsewhere in the Kaapvaal Craton, but are clearly different from the isotopic compositions of on-craton Kaapvaal lamproites (previously known as orangeites). This observation distinguishes the petrogenesis of the Wimbledon, Melton Wold, Droogfontein, and Silvery Home lamproites from those of 'typical' Kaapvaal lamproites. We hypothesize that progressive consumption of enriched and hence fertile K-bearing components in a common sub-lithospheric (i.e. convective mantle) source beneath the southwestern margin of the Kaapvaal Craton might represent a plausible scenario to explain the temporal evolution of petrographic and geochemical traits of the examined lamproites and kimberlites. A source in the lithospheric mantle is considered at odds with the contrasting location of the current localities as they occur both off- and on-craton. Migration of the African plate between 180 and 90 Ma over a relatively stationary convective mantle (plume?) source is not compatible with the spatial–temporal distribution of 'transitional kimberlites'. Instead, we invoke viscous coupling between an upper asthenospheric source and the lithosphere to reconcile a single evolving source with the geographic and age distribution of these rocks. This work supports the hypothesis that olivine lamproites occurring in intra-continental settings share similar genetic features with kimberlites. [ABSTRACT FROM AUTHOR]

Reference materials (RMs) with well‐characterised composition are necessary for reliable quantification and quality control of isotopic analyses of geological samples. For in situRb‐Sr analysis of silicate minerals via laser ablation inductively coupled plasma tandem mass spectrometry (LA‐ICP‐MS/MS) with a collision/reaction cell, there is a general lack of mineral‐specific and matrix‐matched RMs, which limits wider application of this new laser‐based dating technique to certain minerals. In this work, pressed nano‐powder pellets (NP) of four RMs, GL‐O (glauconite), Mica‐Mg (phlogopite), Mica‐Fe (biotite) and FK‐N (K‐feldspar), were analysed and tested for in situRb‐Sr dating, complemented by isotope dilution (ID) MC‐ICP‐MS Rb‐Sr analyses of GL‐O and Mica‐Mg. In addition, we attempted to develop alternative flux‐free and fused 'mineral glasses' from the above RMs for in situRb‐Sr dating applications. Overall, the results of this study showed that among the above RMs only two NP (Mica‐Mg‐NP and GL‐O‐NP) were suitable and robust for in situ dating applications. These two nano‐powder reference materials, Mica‐Mg‐NP and GL‐O‐NP, were thus used as primary RMs to normalise and determine Rb‐Sr ages for three natural minerals: MDC phlogopite and GL‐O glauconite grains, and also Mica‐Fe‐NP (biotite). Our in situ analyses of the above RMs yielded Rb‐Sr ages that are in good agreement (within 8%) of published ages, which suggests that both Mica‐Mg‐NP and GL‐O‐NP are suitable RMs for in situRb‐Sr dating of phlogopite, glauconite and biotite. However, using secondary RMs is recommended to monitor the quality of the obtained ages. [ABSTRACT FROM AUTHOR]