Carlsbad Caverns National Park contains more than 100 hypogenic caves formed 7–14 million years ago and largely isolated from modern surface energy inputs. The environments in the park caves have ...been stable for thousands of years, making them excellent natural laboratories for studying life in extreme environments and the influence of microbes on geologic features. The park was designated a World Heritage Site in 1995, primarily on the basis of the exceptional cave resources. The National Park Service has implemented an adaptive, science-based management plan to protect these resources. This plan uses specific desired conditions appropriate to the cave environment, designated use, and current level of impacts to guide management decisions. Monitoring of resource conditions and trends of any changes are done to ensure that the desired conditions are maintained and whether further management actions are necessary to protect the resources for the enjoyment and study of future generations.
Ordinary chondrites contain two phosphate minerals, merrillite and chlorapatite, both of which are secondary minerals that developed in response to metamorphism on the chondrite parent bodies. We ...have studied the phosphate mineralogy of four LL chondrites, of petrologic types 3.9–6, in order to determine the petrogenesis of the two minerals and interpret the conditions under which they formed. Characterization of merrillite and apatite includes textural observations, mineral compositions determined by electron probe microanalysis, and ion microprobe analyses of trace element and volatile anion elemental abundances. Initial formation of phosphate minerals during mild metamorphism, to petrologic type 4 conditions, resulted in oxidation of P that was originally incorporated in metal, and growth of merrillite as inclusions within metal grains. Subsequent development of both phosphate minerals occurred in response to diffusional equilibration, possible precipitation from fluids as well as replacement reactions resulting from interactions with fluids. Porosity and vein-filling textures in both merrillite and chlorapatite, as well as textures indicating replacement of merrillite by chlorapatite, support a model in which fluid played a significant role and suggest an interface-coupled dissolution–reprecipitation mechanism during metasomatism. Some associations of phosphate minerals with chromite-plagioclase assemblages suggest that phosphate minerals could also be related to impact processes, either as precipitation from an impact melt or as a result of interactions with a fluid or vapor derived from an impact melt. Fluid compositions may have been water-bearing initially, at low temperatures of metamorphism, but later evolved to become halogen-rich and very dry. Late-stage halogen-rich fluids that dominated during cooling of LL chondrite material may have been derived from vaporization of partial melts in the interior of the parent body. Overall, the LL chondrite parent body underwent a complex chemical evolution, in which metasomatism played a significant role.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
AbstractAgricultural crop protection (CP) today is under pressure not the least because it strongly relies on pesticides that negatively affect the environment and human health. Policy attempts to ...induce a transition toward low-pesticide CP have had limited success so far. While the literature has examined these difficulties primarily in terms of farmer decision-making, recent research has begun to highlight the routine nature of farmers’ practices as a key aspect of the inertia of prevailing CP practices. Here we propose a framework that bridges practice theory (PT) and social-psychological concepts. We illustrate the relevance of this framework by gauging the relative roles of individual and structural factors as well as mechanisms that (de)stabilize pesticide-use practices. Our analysis is based on data from a survey conducted among Swiss farmers (n = 652). Using structural equation modeling, we find that structural factors are more strongly associated with pesticide use than individual factors. Although farmers’ personal norms to limit the use of pesticides are activated by values, self-efficacy, and social norms, they do not translate into behavior. Structural factors such as local production conditions and knowledge sourced from private agricultural advisory services appear to inhibit the mediating role of personal norms with respect to pesticide use. We conclude that reconfiguring such structural elements of CP practices may help to disrupt routines and eventually lead to a low-pesticide agriculture. Our findings also highlight the benefits of integrating PT and social-psychological concepts to advance our understanding of routines in CP.
Full text
Available for:
CEKLJ, NUK, ODKLJ, UL, UM, UPUK
Especially poor people in developing countries depend on biological resources to manage their livelihoods and to generate income. Because these resources are usually public goods, their use is often ...subjected to what is known as the tragedy of the commons, potentially leading to resource depletion, environmental degradation, and loss of biodiversity, which consequently undermines the availability and capacity of resources to contribute to residents’ well-being in the long run. We suggest addressing this typical sustainability issue from a new angle. Against the backdrop of identifiable shortcomings within two popular analytic approaches, the capability approach (CA) and the sustainable livelihood approach (SLA), we argue for an improved sustainability framework for analyzing the issue in question. Although we view the CA as encompassing our core ideas regarding human well-being, we propose to enrich it by merging it with the SLA to more adequately include social and environmental capital. To test the framework’s usefulness, we apply it to a case study on the use of medicinal and aromatic plants in the rural livelihood context of Nepal. Thereby, we reveal not only that the creation of capabilities is strongly dependent on the set of capital assets available, particularly in the form of natural capital, but also that the framework provides new perspectives: What matters is developing livelihood strategies that increase people’s opportunity spaces rather than focusing only on those that compensate for missing capabilities or enable people to cope with shocks and vulnerability.
The bulk matrix domain of the Martian breccia NWA 7034 was examined petrographically and isotopically to better understand the provenance and age of the source material that make up the breccia. Both ...147Sm‐143Nd and 146Sm‐142Nd age results for mineral separates from the bulk matrix portion of breccia NWA 7034 suggest that various lithological components in the breccia probably formed contemporaneously ~4.44 Ga ago. This old age is in excellent agreement with the upper intersection ages (4.35–4.45 Ga) for U‐Pb discordia and also concordia defined by zircon and baddeleyite grains in matrix and igneous‐textured clasts. Consequently, we confirm an ancient age for the igneous components that make up the NWA 7034 breccia. Substantial disturbance in the Rb‐Sr system was detected, and no age significance could be gleaned from our Rb‐Sr data. The disturbance to the Rb‐Sr system may be due to a thermal event recorded by bulk‐rock K‐Ar ages of 1.56 Ga and U‐Pb ages of phosphates at about 1.35–1.5 Ga, which suggest partial resetting from an unknown thermal event(s), possibly accompanying breccia formation. The NWA 7034 bulk rock is LREE enriched and similar to KREEP‐rich lunar rocks, which indicates that the earliest Martian crust was geochemically enriched. This enrichment supports the idea that the crust is one of the enriched geochemical reservoirs on Mars that have been detected in studies of other Martian meteorites.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
The martian meteorite Northwest Africa (NWA) 7034 was examined both petrographically and geochemically using several micro-beam techniques including electron probe microanalysis and secondary ion ...mass spectrometry. We have identified various clast types of igneous, sedimentary, and impact origin that occur within the breccia, and we define a classification scheme for these materials based on our observations, although our primary focus here is on the petrology of the igneous clasts. A number of different igneous clasts are present in this meteorite, and our study revealed the presence of at least four different igneous lithologies (basalt, basaltic andesite, trachyandesite, and an Fe, Ti, and P (FTP) rich lithology). These lithologies do not appear to be related by simple igneous processes such as fractional crystallization, indicating NWA 7034 is a polymict breccia that contains samples from several different igneous sources. The basalt lithologies are a good match for measured rock compositions from the martian surface, however more exotic lithologies (e.g., trachyandesite and FTP lithologies) show this meteorite contains previously unsampled rock types from Mars. These new rock types provide evidence for a much greater variety of igneous rocks within the martian crust than previously revealed by martian meteorites, and supports recent rover observations of lithologic diversity across the martian surface. Furthermore, the ancient ages for the lithologic components in NWA 7034 indicate Mars developed this lithologic diversity in the early stages of crust formation.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
A revised diagram plotting the Fe/Mn ratio of pyroxene and olivine verses the anorthite content of plagioclase indicates that the Angrite Parent Body originated from a solar system reservoir with a ...similar Mn-Fe signature to that from which the Earth was derived. The major difference in terrestrial and angritic basalts is the extreme volatile depletion (particularly Na and K) in the latter.Considerable research and publication has been focused on angrite meteorites, which are among the oldest objects in the solar system (∼4.56 Ga; Keil 2012). These meteorites include a silica-undersaturated mafic mineral assemblage. The identity and location of their parent body is still unknown and widely debated. Our new work on angrites SAH 99555, LEW 86010, NWA 10463, LEW 87051, and Angra dos Reis focused on olivine and is interpreted in the context of existing pyroxene and plagioclase data sets. This paper improves the "Mn-Fe in olivine and anorthite content of plagioclase tool for planetary parentage" specifically targeted at finding members of the angrite group of meteorites.
Whitlockite and merrillite are two Ca-phosphate minerals found in terrestrial and planetary igneous rocks, sometimes coexisting with apatite. Whitlockite has essential structural hydrogen, and ...merrillite is devoid of hydrogen. Whitlockite components have yet to be discovered in samples of extraterrestrial merrillite, despite evidence for whitlockite-merrillite solid solution in terrestrial systems. The observation of merrillite in meteoritic and lunar samples has led many to conclude that the magmas from which the merrillite formed were "very dry." However, the Shergotty martian meteorite has been reported to contain both apatite and merrillite, and recently the apatite has been shown to contain substantial OH abundances, up to the equivalent of 8600 ppm H2O. In the present study, we determined the abundances of F, Cl, H2O, and S in merrillite from Shergotty using secondary ion mass spectrometry (SIMS). We determined that the merrillite in Shergotty was properly identified (i.e., no discernible whitlockite component), and it coexists with OH-rich apatite. The absence of a whitlockite component in Shergotty merrillite and other planetary merrillites may be a consequence of the limited thermal stability of H in whitlockite (stable only at T <1050 °C), which would prohibit merrillite-whitlockite solid-solution at high temperatures. Consequently, the presence of merrillite should not be used as evidence of dry magmatism without a corresponding estimate of the T of crystallization. In fact, if a whitlockite component in extraterrestrial merrillite is discovered, it may indicate formation by or equilibration with hydrothermal or aqueous fluids.
Pyroxene is arguably the most powerful, single-phase geochemical and petrologic recorder of Solar System processes, from nebular condensation through planetary evolution, over a wide range of ...temperatures, pressures, and fo2. It is an important mineral phase in the crusts and mantles of evolved planets, in undifferentiated and differentiated asteroids, and in refractory inclusions-the earliest Solar System materials. Here, we review the valence state partitioning behavior of Cr (Cr2+, Cr3+), Ti (Ti3+, Ti4+), and V (V2+, V3+, V4+, V5+) among crystallographic sites in pyroxene over a range of fo2 from approximately fayalite-magnetite-quartz (FMQ) to ∼7 log units below iron-wüstite (IW-7), and decipher how pyroxene can be used as a recorder of conditions of planetary and nebular environments and planetary parentage. The most important crystallographic site in pyroxene with respect to its influence on mineral/melt partitioning is M2; its Ca content has a huge effect on partitioning behavior, because the large Ca cation expands the structure. As a result, distribution coefficients (Ds) for Cr and V increase with increasing Ca content from orthopyroxene to pigeonite to augite. In addition, it is noted that V3+ is favored over V4+ in olivine and pyroxene. In pyroxene in refractory inclusions, Ti3+ is favored over Ti4+ and incorporation of Ti is facilitated by the high availability of Al for coupled substitution. The most important results from analysis of pyroxene in martian meteorites (e.g., QUE 94201) are the oxygen fugacity estimates of IW+0.2 and IW+0.9 derived from partitioning and valence data for Cr and V, respectively, obtained from experiments using appropriate temperatures and melt compositions. In angrites, changes in V valence state may translate to changes in fo2, from IW-0.7 during early pyroxene crystallization, to IW+0.5 during later episodes of pyroxene crystallization. In addition to fo2, the partitioning behavior of Cr, V, and Ti between pyroxene and melt is also dependent upon availability of other cations, especially Al, for charge-balancing coupled substitutions.
Bats play crucial ecological roles and provide valuable ecosystem services, yet many populations face serious threats from various ecological disturbances. The North American Bat Monitoring Program ...(NABat) aims to use its technology infrastructure to assess status and trends of bat populations, while developing innovative and community‐driven conservation solutions.
Here, we present NABat ML, an automated machine‐learning algorithm that improves the scalability and scientific transparency of NABat acoustic monitoring. This model combines signal processing techniques and convolutional neural networks (CNNs) to detect and classify recorded bat echolocation calls. We developed our CNN model with internet‐based computing resources (‘cloud environment’), and trained it on >600,000 spectrogram images. We also incorporated species range maps to improve the robustness and accuracy of the model for future ‘unseen’ data. We evaluated model performance using a comprehensive, independent, holdout dataset.
NABat ML successfully distinguished 31 classes (30 species and a noise class) with overall weighted‐average accuracy and precision rates of 92%, and ≥90% classification accuracy for 19 of the bat species. Using a single cloud‐environment computing instance, the entire model training process took <16 h.
Synthesis and applications. Our convolutional neural network (CNN)‐based model, NABat ML, classifies 30 North American bat species using their recorded echolocation calls with an overall accuracy of 92%. In addition to providing highly accurate species‐level classification, NABat ML and its outputs are compatible with Bayesian and other statistical techniques for measuring uncertainty in classification. Our model is open‐source and reproducible, enabling future implementations as software on end‐user devices and cloud‐based web applications. These qualities make NABat ML highly suitable for applications ranging from grassroots community science initiatives to big‐data methods developed and implemented by researchers and professional practitioners. We believe the transparency and accessibility of NABat ML will encourage broad‐scale participation in bat monitoring, and enable development of innovative solutions needed to conserve North American bat species.
Our convolutional neural network (CNN)‐based model, NABat ML, classifies 30 North American bat species using their recorded echolocation calls with an overall accuracy of 92%. In addition to providing highly accurate species‐level classification, NABat ML and its outputs are compatible with Bayesian and other statistical techniques for measuring uncertainty in classification. Our model is open‐source and reproducible, enabling future implementations as software on end‐user devices and cloud‐based web applications. These qualities make NABat ML highly suitable for applications ranging from grassroots community science initiatives to big‐data methods developed and implemented by researchers and professional practitioners. We believe the transparency and accessibility of NABat ML will encourage broad‐scale participation in bat monitoring, and enable development of innovative solutions needed to conserve North American bat species.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
PDF
