Micro-mechanical failure analysis of wet granular matter

We employ a novel fluid–particle model to study the shearing behavior of granular soils under different saturation levels, ranging from the dry material via the capillary bridge regime to higher saturation levels with percolating clusters. The full complexity of possible liquid morphologies Scheel et al. (Nat Mater 7(3):189–193, 2008. doi: 10.1038/nmat2117) is taken into account, implying the formation of isolated arbitrary-sized liquid clusters with individual Laplace pressures that evolve by liquid exchange via films on the grain surface Melnikov et al. (Phys Rev E 92(022):206, 2015. doi: 10.1103/PhysRevE.92.022206). Liquid clusters can grow in size, shrink, merge and split, depending on local conditions, changes of accessible liquid and the pore space morphology determined by the granular phase. This phase is represented by a discrete particle model based on contact dynamics Brendel et al. (Contact dynamics for beginners. Wiley-VCH, Weinheim, 2005. doi: 10.1002/352760362X.ch14), where capillary forces exerted from a liquid phase add to the motion of spherical particles. We study the macroscopic response of the system due to an external compression force at various liquid contents with the help of triaxial shear tests. Additionally, the change in liquid cluster distributions during the compression due to the deformation of the pore space is evaluated close to the critical load.     

Visualizing flood risk,enabling participation and supporting climate change adaptation using the Geoweb: the case of coastal communities in Nova Scotia,Canada

Impacts of climate change have been observed in natural systems and are expected to intensify in future decades (IPCC in Contribution of Working Groups I, II and III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change IPPC, Geneva, 2014). Governments are seeking to establish adaptive measures for minimizing the effects of climate change on vulnerable citizen groups, economic sectors and critical infrastructure (Adger et al. in Global Environ Change 15(2):77–86, 2005. doi: 10.1016/j.gloenvcha.2004.12.005; Smit and Wandel in Global Environ Change 16(3):282–292, 2006. doi: 10.1016/j.gloenvcha.2006.03.008). Coastal areas are particularly vulnerable to changing conditions due to rising sea levels and storm event intensification that produce new flood exposures (Richards and Daigle in Government of Prince Edward Island, Halifax, Nova Scotia, 2011 http://www.gov.pe.ca/photos/original/ccscenarios.pdf). However, communities oftentimes lack access to locally-relevant climate change information that can support adaptation planning. This research introduces the use of a Geoweb tool for supporting local climate change adaptation efforts in coastal Canadian communities. The Geoweb tool (called “AdaptNS”) is a web-based visualization tool that displays interactive flood exposure maps generated using local climate change projections of sea level rise and storm surge impacts between the years 2000 and 2100. AdaptNS includes participatory features that allow users to identify and share specific locations to protect against present and future coastal flood events. By soliciting feedback from community members, AdaptNS is shown to support local adaptation through the provision of flood exposure visuals, as a platform for identifying adaptation priorities, and as an avenue to communicate local risks to external entities that could facilitate local adaptation initiatives (e.g. upper levels of government). Future Geoweb research directions include improving the visualization of climate change projection uncertainties, the expansion of informational and participation capabilities, and understanding the potential for long-term adoption of Geoweb tools in adaptation decision-making.     

Information infrastructure for Australia’s Integrated Marine Observing System

Australia’s Integrated Marine Observing System (IMOS, imos.org.au) is research infrastructure to establish an enduring observing program for Australian oceanic waters and shelf seas. The observations cover physical, biological, and chemical variables to address themes of multi-decadal ocean change, climate variability and weather extremes, boundary currents and inter-basin flows, continental shelf processes and ecosystem responses.IMOS observations are collected by national facilities based on various platform types and operated by partner institutions around the country. In this paper we describe the infrastructure and workflows developed to manage and distribute the data to the public. We highlight the existing standards and open-source software we have adopted, and the contributions we have made. To demonstrate the value of this infrastructure we provide some illustrations of use and uptake.All IMOS data are freely and openly available to the public via the Ocean Portal (https://imos.aodn.org.au). All IMOS-developed software is open-source and accessible at https://github.com/aodn.     

Comparison of two-dimensional flood propagation models: SRH-2D and Hydro_AS-2D

This article presents a comparison between two two-dimensional finite volume flood propagation models: SRH-2D and Hydro_AS-2D. The models are compared using an experimental dam-break test case provided by Soares-Frazão (J Hydraul Res, 2007. doi: 10.1080/00221686.2007.9521829). Four progressively refined meshes are used, and both models react adequately to mesh and time step refinement. Hydro_AS-2D shows some unphysical oscillations with the finest mesh and a certain loss of accuracy. For that test case, Hydro_AS-2D is more accurate for all meshes and generally faster than SRH-2D. Hydro_AS-2D reacts well to automatic calibration with PEST, whereas SRH-2D has some difficulties in retrieving the suggested Manning’s roughness coefficient.     

Discussion on the article “Paleoseismological analysis of an intraplate extensional structure: the Concud fault (Iberian Chain,Eastern Spain)” by P. Lafuente,L. E. Arlegui,C. L. Liesa,and J. L. Simón (Int J Earth Sci)

This discussion is focused on three aspects of the paper published by Lafuente et al. (Int J Earth Sci, doi: 10.1007/s00531-010-0542-1, 2010) on Concud Fault, constitute the fundamental basis to assess the seismic potential of this capable structure: (1) A slip rate estimated for the Concud Fault based on an erroneous displacement value and a questionable correlation, obviating previously published datings, markedly different to those used by the authors. The wrong displacement value introduces an error of more than 25% in the calculated Quaternary slip rate. (2) A new paleoseismological interpretation of the outcrop of Condud Fault at Los Baños, adding two improperly justified paleoearthquakes to the four events previously inferred. (3) The attribution of faults affecting a young terrace to the most recent recorded earthquake on Concud Fault, ruling out implicitly the likely option of a gravitational origin for them, either landsliding or subsidence due to evaporite dissolution.     

Evaluation of the potential for gas leakage along wellbores in the St. Lawrence Lowlands basin,Quebec, Canada

Wellbore attributes (i.e., deviation, casings and plugging characteristics) for 85 wells in the St. Lawrence Lowlands basin of southern Quebec were compiled from drilling reports and abandonment programs to provide an overview of the abandoned well characteristics and to establish a diagnosis on the long-term reliability of the completion and abandonment practices carried out by the companies since the beginning of oil and gas exploration. Using these data, the conventional and unconventional wells were divided into four categories: (1) conventional wells drilled before 1950, (2) conventional wells drilled between 1950 and 1970, (3) conventional wells drilled after 1970 and shale gas wells (all drilled after 2000). Very little information was available for wells drilled before 1950. More information was available for the wells drilled from 1950 to 1970 which is considered a transition period between old and modern technology. Conventional and unconventional wells drilled after 1970 were generally well documented and their attributes corresponded to API standards. A decision tree, inspired from the methodology proposed by Watson and Bachu (SPE Drill Complet 24(1):115–126, 2009.  https://doi.org/10.2118/106817-PA), was then created to assess the potential of leakage of each of the conventional and unconventional wells using the compiled attributes. The factors defining the probability of well leakage were wellbore deviation, height of cement in casing annuli (partially or fully cemented), type of abandonment plugs (cement or mechanical plugs) and drilling date (before or after 1970). Among the 85 wells assessed by this tree, the probability of leakage was higher than 50% for 55 wells (65% of wells). Wellbore deviation and lack of information on the construction and abandonment methods were respectively the primary and secondary causes of high probability of leakage of these wells.     

REVIEW OF THALLIUM,ITS GEOCHEMISTRY,MINERALOGY, PRINCIPAL GENETIC TYPES OF DEPOSITS,AND GEOCHEMICAL PROVINCES BY V.V. IVANOV,V.YU. VOLGIN,A.A. KRASNOV AND N.V. LIZUNOV

This book review takes the authors to task for omitting numerous references when they wrote this first comprehensive work on thallium. Among the omissions noted are; 1) the extreme toxicity of thallium; 2) the occurrence of thallium in various minerals:

REVIEW OF THALLIUM, ITS GEOCHEMISTRY, MINERALOGY, PRINCIPAL GENETIC TYPES OF DEPOSITS, AND GEOCHEMICAL PROVINCES BY V.V. IVANOV, V.YU. VOLGIN, A.A. KRASNOV AND N.V. LIZUNOV

All authors

V. V. Mogarovskiy

https://doi.org/10.1080/00206816409473950

Published online:

20 September 2010

Table     

ORDOVICIAN GRAPTOLITES OF THE CHU-ILIYSKIYE MOUNTAINS

The available information on the graptolite faunas of the Chu-Illyskiye Mountains is synthesized and comparisons made with other faunas of Kazakhstan, Europe, North America, and China. Comparison with Bet-Pak-la, 400 km NW of the Chu-Iliyskiye, shows almost no species common to contemporaneous units, a discrepancy attributed to facies differences. Correlation with the English standard is good although many details of zonal equation are arbitrary. Fifty species, of which 17 are new, are described and illustrated. Twenty-two are typically European, five North American, two Russian, and one Chinese; three are not formally named. Correlation between the graptolite zones of the Chu-Iliyskiye Mountains and the English standard zones is as follows:

ORDOVICIAN GRAPTOLITES OF THE CHU-ILIYSKIYE MOUNTAINS

All authors

B.M. Keller

https://doi.org/10.1080/00206816209474672

Published online:

01 September 2009

Table     

A Refined Model for Solid Particle Rock Erosion

A procedure for the estimation of distribution parameters of a Weibull distribution model K₁ = f(K_Ic^12/4/σ_C^23/4) for solid particle erosion, as recently suggested in Rock Mech Rock Eng, doi: 10.1007/s00603-014-0658-x, 2014, is derived. The procedure is based on examinations of elastic–plastically responding rocks (rhyolite, granite) and plastically responding rocks (limestone, schist). The types of response are quantified through SEM inspections of eroded surfaces. Quantitative numbers for the distribution parameter K₁ are calculated for 30 rock materials, which cover a wide range of mechanical properties. The ranking according to the parameter K₁ is related to qualitative rock classification schemes. A modified proposal for the erosion of schist due to solid particle impingement at normal incidence is introduced.     

Evaluating climate change adaptation efforts on the US 50 states’ hazard mitigation plans

Climate change brings uncertain risks of climate-related natural hazards. The US Federal Emergency Management Agency (FEMA in Climate change: long-term trends and their implications for emergency management, 2011. https://www.fema.gov/pdf/about/programs/oppa/climate_change_paper.pdf) has issued a policy directive to integrate climate change adaptation actions into hazard mitigation programs, policies, and plans. However, to date there has been no comprehensive empirical study to examine the extent to which climate change issues are integrated into state hazard mitigation plans (SHMPs). This study develops 18 indicators to examine the extent of climate change considerations in the 50 SHMPs. The results demonstrate that these SHMPs treat climate change issues in an uneven fashion, with large variations present among the 50 states. The overall plan quality for climate change considerations was sustained at an intermediate level with regard to climate change-related awareness, analysis, and actions. The findings confirm that climate change concepts and historic extreme events have been well recognized by the majority of SHMPs. Even though they are not specific to climate change, mitigation and adaptation strategies that can help reduce climate change risks have been adopted in these plans. However, the plans still lack a detailed assessment of climate change and more incentives for collaboration strategies beyond working with emergency management agencies.     

An ontology for satellite databases

This paper demonstrates the development of ontology for satellite databases. First, I create a computational ontology for the Union of Concerned Scientists (UCS) Satellite Database (UCSSD for short), called the UCS Satellite Ontology (or UCSSO). Second, in developing UCSSO I show that The Space Situational Awareness Ontology (SSAO) (Rovetto & Kelso 2016)-—an existing space domain reference ontology—-and related ontology work by the author (Rovetto 2015, 2016) can be used either (i) with a database-specific local ontology such as UCSSO, or (ii) in its stead. In case (i), local ontologies such as UCSSO can reuse SSAO terms, perform term mappings, or extend it. In case (ii), the author’s orbital space ontology work, such as the SSAO, is usable by the UCSSD and organizations with other space object catalogs, as a reference ontology suite providing a common semantically-rich domain model. The SSAO, UCSSO, and the broader Orbital Space Environment Domain Ontology project is online at https://purl.org/space-ontology and GitHub. This ontology effort aims, in part, to provide accurate formal representations of the domain for various applications. Ontology engineering has the potential to facilitate the sharing and integration of satellite data from federated databases and sensors for safer spaceflight.     

Application of Binary Permeability Fields for the Study of $${\hbox {CO}_{2}}$$ Leakage from Geological Carbon Storage in Saline Aquifers of the Michigan Basin

The feasibility of geological carbon storage (GCS) sites depends on their capacity to retain safely \({\hbox {CO}_{2}}\). While deep saline formations and depleted gas/oil reservoirs are good candidates to sequester \({\hbox {CO}_{2}}\), gas/oil reservoirs typically have a limited storage capacity compared to ideal targets (\(\sim \) 1 Mt/year) considered for \({\hbox {CO}_{2}}\) disposal (Celia et al. in Water Resour Res 51(9):6846–6892, 2015. doi: 10.1002/2015WR017609). In this respect, deep saline aquifers are considered more appropriate formations for GCS, but present the disadvantage of having limited characterization data. In particular, information about the continuity of the overlying sealing formations (caprock) is often sparse if it exists at all. In this work, a study of \({\hbox {CO}_{2}}\) leakage is conducted for a candidate GCS site located in the Michigan Basin, whose sealing properties of the caprock are practically unknown. Quantification of uncertainty on \({\hbox {CO}_{2}}\) leakage from the storage formation is achieved through a Monte Carlo simulation approach, relying on the use of a computationally efficient semi-analytical leakage model based upon the solution derived by Nordbotten et al. (Environ Sci Technol 43(3):743–749, 2009), which assumes leakage occurs across “passive” wells intersecting caprock layers. A categorical indicator Kriging simulator is developed and implemented to represent the caprock sealing properties and model the permeability uncertainty. Binary fields of caprock permeability are generated and exhibit mostly low permeability, with sparsely-occurring local high permeability areas where brine and \({\hbox {CO}_{2}}\) may leak out of the storage formation. In addition, the feasibility of extending the use of the semi-analytical model to large-area leakage pathways is studied. This work advances a methodology for preliminary uncertainty quantification of \({\hbox {CO}_{2}}\) leakage at sites of GCS with little or no information on the sealing properties of the caprock. The implemented analysis shows that, for the considered site, \({\hbox {CO}_{2}}\) leakage may not be negligible even for relatively low (\(\sim \) 1%) probabilities of finding permeable inclusions in the caprock and highlights the importance of being able to characterize caprock sealing properties over large areas.     

A method for modelling coastal erosion risk: the example of Scotland

It is thought that 70% of beaches worldwide are experiencing erosion (Bird in Coastline changes: a global review, Wiley, Hoboken, 1985), and as global sea levels are rising and expected to accelerate, the management of coastal erosion is now a shared global issue. This paper aims to demonstrate a method to robustly model both the incidence of the coastal erosion hazard, the vulnerability of the population, and the exposure of coastal assets to determine coastal erosion risk, using Scotland as a case study. In Scotland, the 2017 Climate Change Risk Assessment for Scotland highlights the threat posed by coastal erosion to coastal assets and the Climate Change (Scotland) Act 2009 requires an Adaptation Programme to address the risks posed by climate change. Internationally, an understanding and adaption to coastal hazards is imperative to people, infrastructure and economies, with Scotland being no exception. This paper uses a Coastal Erosion Susceptibility Model (CESM) (Fitton et al. in Ocean Coast Manag 132:80–89. https://doi.org/10.1016/j.ocecoaman.2016.08.018 , 2016) to establish the exposure to coastal erosion of residential dwellings, roads, and rail track in Scotland. In parallel, the vulnerability of the population to coastal erosion, using a suite of indicators and Experian Mosaic Scotland geodemographic classification, is also presented. The combined exposure and vulnerability data are then used to determine coastal erosion risk in Scotland. This paper identifies that 3310 dwellings (a value of £524 m) are exposed to erosion, and the Coastal Erosion Vulnerability Index (CEVI) identifies 1273 of these are also considered to be highly vulnerable to coastal erosion, i.e. at high risk. Additionally, the CESM classified 179 km (£1.2 bn worth) of road and 13 km of rail track (£93 m to £2 bn worth) to be exposed. Identifying locations and assets that are exposed and at risk from coastal erosion is crucial for effective management and enables proactive, rather that reactive, decisions to be made at the coast. Natural hazards and climate change are set to impact most on the vulnerable in society. It is therefore imperative that we begin to plan, manage, and support both people and the environment in a manner which is socially just and sustainable. We encourage a detailed vulnerability analysis, such as the CEVI demonstrated here for Scotland, to be included within future coastal erosion risk research. This approach would support a more sustainable and long-term approach to coastal management decisions.     

The role of eclogite in the mantle heterogeneity at Cape Verde

The Cape Verde hotspot, like many other Ocean Island Basalt provinces, demonstrates isotopic heterogeneity on a 100–200 km scale. The heterogeneity is represented by the appearance of an EM1-like component at several of the southern islands and with a HIMU-like component present throughout the archipelago. Where the EM1-like component is absent, a local DMM-like component replaces the EM1-like component. Various source lithologies, including peridotite, pyroxenite and eclogite have been suggested to contribute to generation of these heterogeneities; however, attempts to quantify such contributions have been limited. We apply the minor elements in olivine approach (Sobolev et al. in Nature 434:590–597, 2005; Science, doi: 10.1126/science.1138113, 2007), to determine and quantify the contributions of peridotite, pyroxenite and eclogite melts to the mantle heterogeneity observed at Cape Verde. Cores of olivine phenocrysts of the Cape Verde volcanics have low Mn/FeO and low Ni*FeO/MgO that deviate from the negative trend of the global array. The global array is defined by mixing between peridotite and pyroxenite, whereas the Cape Verde volcanics indicate contribution of an additional eclogite source. Eclogite melts escape reaction with peridotite either by efficient extraction in an area of poor mantle flow or by reaction of eclogite melts with peridotite, whereby an abundance of eclogite can seal off the melt from further reaction. Temporal trends of decreasing Mn/FeO indicate that the supply of eclogite melts is increasing. Modelling suggests the local DMM-like end-member is formed from a relatively peridotite-rich melt, while the EM1-like end-member has a closer affinity to a mixed peridotite–pyroxenite–eclogite melt. Notably the HIMU-like component ranges from pyroxenite–peridotite-rich melt to one with up to 77 % eclogite melt as a function of time, implying that sealing of melt pathways is becoming more effective.     

GOTLANDIAN STRATIGRAPHY OF THE OUTER ZONE OF SOUTHWEST JAPAN

Many localities of the Gotlandian rocks have been found in the Outer Zone of Southwest Japan since Kobayashi and Iwaya's discovery of Halysites-bearing limestone at Imose, Kochi Prefecture, Shikoku in 1940. However, little has been done in their stratigraphy and paleontology. Here, the writer describes a tentative division of the Gotlandian strata with reference to the Halysitidae. The bed G₄, which is composed of thick acidic volcanic and clastic materials, is presumed to be the Gotlandio-Devonian passage bed, and is correlated to the Takainari, Ono and the, lower half of the Nakazato series in the Kitakami mountains, Northeast Honshu, because of the predominance of acidic rocks. The so-called Upper Gotlandian Fukuji formation in Gifu Prefecture, Hida plateau is also brought into comparison. The strong acidic volcanic activities in these Gotlandio-Devonian rocks suggest that the “Oboke sandstone schists” in the lower part of the so-called Sambagawa metamorphic complex of the Sakawa orogenic zone are the G₄ equivalent which has been deposited near the axis of the Chichibu geosyncline. The reef-limestone facies was shifted from the Outer to the Inner Zone of West Japan at the beginning of the Devonian period. Simultaneously with the shifting, Minamihiura and other unconformities might have been produced in the lower part of the Sambagawa system. The Kunimiyarna acidic igneous intrusion was probably the forerunner of this movement. These geological events in Japan may be related to the Kwangsi disturbance in South China.

The stratigraphy of the Gotlandio-Devonian rocks in the Outer Zone of Southwest Japan is in descending order as follows:

GOTLANDIAN STRATIGRAPHY OF THE OUTER ZONE OF SOUTHWEST JAPAN

All authors

Takashi Hamada

https://doi.org/10.1080/00206816209473731

Published online:

01 September 2009

Table     

Isotope fingerprinting of precipitation associated with western disturbances and Indian summer monsoons across the Himalayas

Precipitation samples were collected across the Himalayas from Kashmir (western Himalaya) to Assam (eastern Himalaya) to understand the variation of the stable isotopic content (\(\updelta ^{18}\)O and \(\updelta \)D) in precipitation associated with two dominant weather systems of the region: western disturbances (WDs) and Indian summer monsoon (ISM). Large spatial and temporal variations in isotopic values were noted with \(\updelta ^{18}\)O and \(\updelta \)D values ranging from \(-30.3\) to Open image in new window and \(-228\) to Open image in new window , respectively. The d-excess values also exhibit a large range of variation from \(-30\) to Open image in new window . In general, heavier isotopic values are observed in most of the samples in Jammu, whereas lighter values are observed in majority of the samples in Uttarakhand. Precipitation at Jammu seems to have undergone intense evaporation while that from Uttarakhand suggest normal Rayleigh fractionation/distillation of the air mass as it moves from the source region to the precipitation site and/or orographic lifting. The d-excess of rainfall in Kashmir has a distinctly higher median value of Open image in new window compared to other precipitation sites with a median of Open image in new window . Using distinct isotopic signatures, the regions receiving precipitation from two different weather systems have been identified.     

SHRIMPDB: a new geoanalytical database for U-Th-Pb geochronological data from SHRIMP measurements

This paper introduces a novel web-based database, SHRIMPDB, to support the efficient reutilization of U-Th-Pb geochronological data from sensitive high-resolution ion microprobe (SHRIMP) measurements. In order to provide complete data content that can be reutilized by Earth scientists, a new data model containing analytical data and relevant sample metadata is proposed according to analyses of measurement procedures and the data characteristics of SHRIMP. Vivid data visualization, real-time data query interfaces (including a novel and intuitive polygonal region search), and a pragmatic data management module are designed and implemented using web-based and cloud GIS-based technologies, which provide a platform for Earth scientists to efficiently curate and share SHRIMP data on the internet. An incentive that encourages geochronologists to contribute data is suggested through cooperation between SHRIMPDB and the Beijing SHRIMP center. The database is currently under evaluation at the Beijing SHRIMP center. SHRIMPDB is globally available online at http://202.198.17.27/shrimpdb/home.     

Analytical approximation for the Fe <Emphasis Type="Italic">K</Emphasis><Subscript>α</Subscript> emission line in quasar spectra

The spectra of many Seyfert galaxies display broad Fe K _α emission. The line profile has two maxima, suggesting that the line emerges in the innermost regions of an accretion disk around a black hole, making it necessary to take into account general relativistic (GR) effects. Identifying GR processes occuring in active galactic nuclei (AGN) requires reconstructing the parameters of the accreting system from the line profile using some reasonably quick algorithm. We present here a numerical approximation for the Fe K _α emission line using analytical functions. The approximation encompasses a range of the disk radial coordinate r and the angle θ between the line of sight and the disk normal, and makes it possible to decrease the computing time by six orders of magnitude in certain astrophysical problems, while taking into account all GR effects. Results of the approximation are available at http://www.iki.rssi.ru/people/repin/approx.     

Chemometric evaluation of heavy metals distribution in wastewater irrigated soil of peri-urban area

Characterization of content and source of heavy metals in soils are necessary to establish quality standards on a regional level. In relation to this, two zones, (sampling zone-1) and (sampling zone-2) depending on nature and intensity of wastewater disposal along the peri-urban area of Peshawar, Pakistan were selected. Thirty-six samples of wastewater and topsoil each were collected to determine the content of Pb, Cr, Cd, Cu, Zn, Ni, Fe and Mn, and physico-chemical parameters like pH, electrical conductivity, total solids, total dissolved solids, total suspended solids, and organic matter. Analytical determinations were performed by atomic absorption spectroscopy after microwave sample digestion in acid solution. Chemometric techniques which include hierarchical cluster analysis, principal component analysis, correlation analysis, and tukey test were applied. Concentrations of physico-chemical properties in wastewater and soil were higher in sampling zone-2. Concentrations of six heavy metals in wastewater and two in soil exceeded permissible limits of World Health Organization (Guidelines for drinking water quality, 4th edition, 2011), European Union (Heavy metals in wastes, European commission on environment. http://ec.europa.eu/environment/waste/studies/pdf/heavymetalsreport, 2002). Hierarchical cluster analysis grouped eight heavy metals into two clusters for wastewater and five clusters for soils. Principal component analysis describes four factors possessing Eigenvalues greater than 1.0 and explained the cumulative total variance of 84% with factor 1, having positive loading of anthropogenic metals (Cd, Cu, and Ni). Significant correlation was found between anthropogenic metals like Ni and Cd in water and between Cu and Cr in soil. Further research in other agricultural lands in peri-urban region would improve the basis for proposing such soil quality standards.     

Phase-equilibrium geobarometers for silicic rocks based on rhyolite-MELTS. Part 2: application to Taupo Volcanic Zone rhyolites

Constraining the pressure of crystallisation of large silicic magma bodies gives important insight into the depth and vertical extent of magmatic plumbing systems; however, it is notably difficult to constrain pressure at the level of detail necessary to understand shallow magmatic systems. In this study, we use the recently developed rhyolite-MELTS geobarometer to constrain the crystallisation pressures of rhyolites from the Taupo Volcanic Zone (TVZ). As sanidine is absent from the studied deposits, we calculate the pressures at which quartz and feldspar are found to be in equilibrium with melt now preserved as glass (the quartz +1 feldspar constraint of Gualda and Ghiorso, Contrib Mineral Petrol 168:1033. doi: 10.1007/s00410-014-1033-3. 2014). We use glass compositions (matrix glass and melt inclusions) from seven eruptive deposits dated between ~320 and 0.7 ka from four distinct calderas in the central TVZ, and we discuss advantages and limitations of the rhyolite-MELTS geobarometer in comparison with other geobarometers applied to the same eruptive deposits. Overall, there is good agreement with other pressure estimates from the literature (amphibole geobarometry and H₂O–CO₂ solubility models). One of the main advantages of this new geobarometer is that it can be applied to both matrix glass and melt inclusions—regardless of volatile saturation. The examples presented also emphasise the utility of this method to filter out spurious glass compositions. Pressure estimates obtained with the new rhyolite-MELTS geobarometer range between ~250 to ~50 MPa, with a large majority at ~100 MPa. These results confirm that the TVZ hosts some of the shallowest rhyolitic magma bodies on the planet, resulting from the extensional tectonic regime and thinning of the crust. Distinct populations with different equilibration pressures are also recognised, which is consistent with the idea that multiple batches of eruptible magma can be present in the crust at the same time and can be tapped simultaneously by large eruptive events.