Compounding impacts of hazard exposures on mental health in Houston,TX

Natural Hazards - Natural and anthropogenic hazards are increasingly becoming commonplace due to climate change and population pressures. The state of Texas is particularly vulnerable to these...     

Some challenges of monitoring a potentially active volcanic field in a large urban area: Auckland volcanic field,New Zealand

Natural Hazards - The city of Auckland (population 1.3 million) is built on and around a potentially active basaltic intraplate volcanic system, the Auckland volcanic field. This...     

Geosite of a steep lava spatter cone of the 1256 AD, Al Madinah eruption, Kingdom of Saudi Arabia

UNESCO promotes geoconservation through various programs intended to establish an inventory of geologically and geomorphologically significant features worldwide that can serve as an important database to understand the Earth’s global geoheritage. An ultimate goal of such projects globally is to establish geoparks that represent an integrated network of knowledge transfer opportunities, based on a specific array of geological and geomorphological sites able to graphically demonstrate how the Earth works to the general public. In these complex geoconservation and geoeducational programs, the identification of significant geological and geomorphological features is very important. These are commonly referred to as ‘geosites’ or ‘geomorphosites’, depending on whether the feature or processes the site demonstrates is more geological or geomorphological, respectively. The Kingdom of Saudi Arabia is an extraordinary place due to its arid climate and therefore perfect exposures of rock formations. The Kingdom is also home to extensive volcanic fields, named “harrats” in Arabic, referring particularly to the black, basaltic lava fields that dominate the desert landscape. Current efforts to increase awareness of the importance of these volcanic fields in the geological landscape of Arabia culminated in the first proposal to incorporate the superbly exposed volcanic features into an integrated geoconservation and geoeducation program that will hopefully lead to the development of a geopark named, “The Harrat Al Madinah Volcanic Geopark” [1]. Here we describe one of the extraordinary features of the proposed Harrat Al Madinah Volcanic Geopark, namely a steep lava spatter cone formed during a historical eruption in 1256 AD.     

Øvre Æråsvatn - palynostratigraphy of a 22,000 to 10,000 BP lacustrine record on Andøya, northern Norway

Radiocarbon datings of a 4.10 m long lacustrine sequence from Lake Øvre Æråsvatn reveal continuous sediment accumulation during most of the Late Weichselian. starting before 21.800 ± 410 BP. The pollen record for the period 21,800 to 12,800 RP is uniform and is strongly dominated by Poaceae. Pollen influx variations suggest a succession of climatic ameliorations and deteriorations. Low to Middle Arctic. interstadial conditions prevailed from 21.000 to 19.650 (19.000) BP. A pronounced climatic deterioration followed. culminating at c. 18,85018,500 BP. synchronous with a glacial advance over the nearby Endletvatn and Nedre Æråsvatn basins At c 18.300 BP. a climatic amelioration triggered important changes in the lacustrine environment. Organogenic gyttja (2.56 m) accumulated from 18,300 to 15,000 BP. indicating a eutrophic lacustrine environment. Sparsity of minerogenic material suggests an arid climate with low surface runoff. Further ameliorations occurred from c. 17,400 to 16,800 BP and 16,000 to 15,000 BP. From c. 15.000 BP onwards. a climatic deterioration is indicated. The 17,800 to 10,500 BP record is fragmentary. At c. 10,500 BP. an improving climate induced establishment of Betula nana –Empetrum heaths. rapidly succeeded by mesic Betula pubescens Filipendula woodlands.     

Zero-valent iron and organic carbon mixtures for remediation of acid mine drainage: Batch experiments

A series of laboratory batch experiments was conducted to evaluate the potential for treatment of acid mine drainage (AMD) using organic C (OC) mixtures amended by zero-valent Fe (Fe⁰). Modest increases in SO₄ reduction rates (SRRs) of up to 15% were achieved by augmenting OC materials with 5 and 10 dry wt% Fe⁰. However, OC was essential for supporting SO₄ reducing bacteria (SRB) and therefore SO₄ reduction. This observation suggests a general absence of autotrophic SRB which can utilize H₂ as an electron donor. Sulfate reduction rates (SRRs), calculated using a mass-based approach, ranged from −12.9 to −14.9 nmol L⁻¹ d⁻¹  g⁻¹ OC. Elevated populations of SRB, iron reducing bacteria (IRB), and acid producing (fermentative) bacteria (APB) were present in all mixtures containing OC. Effective removal of Fe (91.6–97.6%), Zn (>99.9%), Cd (>99.9%), Ni (>99.9%), Co (>99.9%), and Pb (>95%) was observed in all reactive mixtures containing OC. Abiotic metal removal was achieved with Fe⁰ only, however Fe, Co and Mn removal was less effective in the absence of OC. Secondary disordered mackinawite [Fe_1+xS] was observed in field-emission scanning electron microscopy (FE-SEM) backscatter electron micrographs of mixtures that generated SO₄ reduction. Energy dispersive X-ray (EDX) spectroscopy revealed that Fe–S precipitates were Fe-rich for mixtures containing OC and Fe⁰, and S-rich in the absence of Fe⁰ amendment. Sulfur K-edges determined by synchrotron-radiation based bulk X-ray absorption near-edge structure (XANES) spectroscopy indicate solid-phase S was in a reduced form in all mixtures containing OC. Pre-edge peaks on XANES spectra suggest tetragonal S coordination, which is consistent with the presence of an Fe–S phase such as mackinawite. The addition of Fe⁰ enhanced AMD remediation over the duration of these experiments, however long-term evaluation is required to identify optimal Fe⁰ and OC mixtures.     

THE ROLE OF ATMOSPHERIC CIRCULATION PATTERNS IN AGROCLIMATE VARIABILITY IN FINLAND, 1961–2011

This study evaluates interannual variations and trends in growing season daily temperature sum and daily precipitation sum in Finland during 1961–2011, and their connections to well known atmospheric circulation patterns. Changes in summer (June–August) climate partially explain changes in growing season daily temperature sum and daily precipitation sum over Finland, which naturally decreased from south to north. On a national scale, growing season warmed and became wetter during 1961–2011, as growing season daily temperature sum and daily precipitation sum significantly (p < 0.05) increased by 5.01 ± 3.17°C year^–1 and 1.39 ± 0.91 mm year^–1, respectively. The East Atlantic pattern was the most influential atmospheric circulation pattern for variations in growing season daily temperature sum (rho = 0.40) across Finland and the East Atlantic/West Russia pattern was most influential for growing season daily precipitation sum variability (rho = –0.54). There were significant (p < 0.05) increasing trends in growing season daily temperature sum and daily precipitation sum throughout Finland during 1961–2011. Increased growing season daily temperature sum was mainly observed in northern, central, western, eastern and coastal areas of south‐western Finland. This warming was positively associated with the East Atlantic pattern in the north, centre and south, but negatively associated with the East Atlantic/West Russia pattern in eastern Finland. Increased GSP mostly occurred in southern, eastern, western, central, northern and north‐western Finland. These wetting trends were positively correlated with the East Atlantic pattern in the north and negatively correlated with the Polar pattern in the south and the East Atlantic/West Russia pattern in the east, west, centre and north‐east of Finland. The overall agroclimatic year‐to‐year variability in Finland between 1961 and 2011 was mostly linked to variations in the East Atlantic and East Atlantic/West Russia patterns.     

The tectonics and mineral systems of Proterozoic Western Australia:Relationships with supercontinents and global secular change

The cratonisation of Western Australia during the Proterozoic overlapped with several key events in the evolution of Earth. These include global oxidation events and glaciations, as well as the assembly,accretionary growth, and breakup of the supercontinents Columbia and Rodinia, culminating in the assembly of Gondwana. Globally, Proterozoic mineral systems evolved in response to the coupled evolution of the atmosphere, hydrosphere, biosphere and lithosphere. Consequently, mineral deposits form preferentially in certain times, but they also require a favourable tectonic setting. For Western Australia a distinct plate-margin mineralisation trend is associated with Columbia, whereas an intraplate mineralisation trend is associated with Rodinia and Gondwana, each with associated deposit types. We compare the current Proterozoic record of ore deposits in Western Australia to the estimated likelihood of oredeposit formation. Overall likelihood is estimated with a simple matrix-based approach that considers two components: The "global secular likelihood" and the "tectonic setting likelihood". This comparative study shows that at least for the studied ore-deposit types, deposits within Western Australia developed at times, and in tectonic settings compatible with global databases. Nevertheless, several deposit types are either absent or poorly-represented relative to the overall likelihood models. Insufficient exploration may partly explain this, but a genuine lack of deposits is also suggested for some deposit types. This may relate either to systemic inadequacies that inhibited ore-deposit formation, or to poor preservation. The systematic understanding on the record of Western Australia helps to understand mineralisation processes within Western Australia and its past connections in Columbia, Rodinia and Gondwana and aids to identify regions of high exploration potential.     

A machine learning approach for regional geochemical data:Platinum-group element geochemistry vs geodynamic settings of the North Atlantic Igneous Province

Whilst traditional approaches to geochemistry provide valuable insights into magmatic processes such as melting and element fractionation, by considering entire regional data sets on an objective basis using machine learning algorithms(MLAs), we can highlight new facets within the broader data structure and significantly enhance previous geochemical interpretations.The platinum-group element(PGE) budget of lavas in the North Atlantic Igneous Province(NAIP) has been shown to vary systematically according to age, geographic location and geodynamic environment.Given the large multi-element geochemical data set available for the region, MLAs were employed to explore the magmatic controls on these shifting concentrations.The key advantage of using machine learning in analysis is its ability to cluster samples across multi-dimensional(i.e., multi-element)space.The NAIP data set is manipulated using Principal Component Analysis(PCA) and t-Distributed Stochastic Neighbour Embedding(t-SNE) techniques to increase separability in the data alongside clustering using the k-means MLA.The new multi-element classification is compared to the original geographic classification to assess the performance of both approaches.The workflow provides a means for creating an objective high-dimensional investigation on a geochemical data set and particularly enhances the identification of metallogenic anomalies across the region.The techniques used highlight three distinct multi-element end-members which successfully capture the variability of the majority of elements included as input variables.These end-members are seen to fluctuate in prominence throughout the NAIP, which we propose reflects the changing geodynamic environment and melting source.Crucially, the variability of Pt and Pd are not reflected in MLA-based clustering trends, suggesting that they vary independently through controls not readily demonstrated by the NAIP major or trace element data structure(i.e., other proxies for magmatic differentiation).This data science approach thus highlights that PGE(here signalled by Pt/Pd ratio) may be used to identify otherwise localised or cryptic geochemical inputs from the subcontinental lithospheric mantle(SCLM) during the ascent of plume-derived magma, and thereby impact upon the resulting metallogenic basket.     

Experimental aqueous alteration of cometary dust

Abstract– Recent spacecraft missions to comets have reopened a long‐standing debate about the histories and origins of cometary materials. Comets contain mixtures of anhydrous minerals and ices seemingly unaffected by planetary processes, yet there are indications of a hydrated silicate component. We have performed aqueous alteration experiments on anhydrous interplanetary dust particles (IDPs) that likely derived from comets. Hydrated silicates rapidly formed from submicrometer amorphous silicates within the IDPs at room temperature in mildly alkaline solution. Hydrated silicates may thus form in the near‐surface regions of comets if liquid water is ever present. Our findings provide insight into origins of cometary IDPs containing both anhydrous and hydrated minerals and help reconcile the seemingly inconsistent observations of hydrated silicates from the Stardust and Deep Impact missions.