Erratum to: Second California Assessment: integrated climate change impacts assessment of natural and managed systems. Guest editorial     

Guido Franco  Daniel R. Cayan  Susanne Moser  Michael Hanemann  Myoung-Ae Jones 《Climatic change》2012,113(3-4):1099-1100

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Crystallization and impact history of a meteoritic sample of early lunar crust(NWA 3163)refined by atom probe geochronology     

L.F.White  D.E.Moser  K.T.Tait  B.Langelier  I.Barker  J.R.Darling 《地学前缘(英文版)》2019,10(5):1841-1848

Granulitic lunar meteorites offer rare insights into the timing and nature of igneous,metamorphic and impact processes in the lunar crust.Accurately dating the different events recorded by these materials is very challenging,however,due to low trace element abundances(e.g.Sm,Nd,Lu,Hf),rare micrometerscale U-Th-bearing accessory minerals,and disturbed Ar-Ar systematics following a multi-stage history of shock and thermal metamorphism.Here we report on micro-baddeleyite grains in granulitic mafic breccia NWA 3163 for the first time and show that targeted microstructural analysis(electron backscatter diffraction)and nanoscale geochronology(atom probe tomography)can overcome these barriers to lunar chronology.A twinned(～90°/401)baddeleyite domain yields a ~(232)Th/~(208)Pb age of 4328 ± 309 Ma,which overlaps with a robust secondary ion mass spectrometry(SIMS)~(207)Pb/~(206)Pb age of 4308 ± 18.6 Ma and is interpreted here as the crystallization age for the igneous protolith of NWA 3163.A second microstructural domain,2μm in width,contains patchy overprinting baddeleyite and yields a Th-Pb age of 2175 ±143 Ma,interpreted as dating the last substantial impact event to affect the sample.This finding demonstrates the potential of combining microstructural characterization with nanoscale geochronology when resolving complex P-T-t histories in planetary materials,here yielding the oldest measured crystallization age for components of lunar granulite NWA 3163 and placing further constraints on the formation and evolution of lunar crust.  相似文献   

Tidal effects on phytoplankton assemblages in a near‐pristine estuary: a trait‐based approach for the case of a shallow tropical ecosystem in Brazil          下载免费PDF全文

Gleyci A. O. Moser  Fernanda Reinhardt Piedras  Anna Beatriz J. Oaquim  Daiana S. Souza  Suzana G. Leles  Domênica T. de Lima  Ana Beatriz A. Ramos  Cássia de O. Farias  Alexandre M. Fernandes 《Marine Ecology》2017,38(4)

The study of near‐pristine estuaries can be used as a tool for mitigation projects of harmful effects in anthropogenic eutrophic systems, since one can analyze the effect of temporal and spatial variations generated mainly by natural forces. Phytoplankton taxonomy has been used as a classical indicator to assess changes in transitional water communities, however alternative methods based on morphological, behavioral and physiological traits offer the opportunity to compare sites or moments with different taxonomic compositions. Our goal, in this context, is to evaluate phytoplankton community short‐term and seasonal variability in a near‐pristine estuary, Barra Grande estuary (Ilha Grande, RJ, Brazil), through species functional traits and thus community functional diversity. Samplings were carried out in a mooring in complete tidal cycles, seasonally during 2012. Our results showed a diverse phytoplankton community with 38 frequent and abundant taxa, marked by density variation (1.2 × 10.4–2 × 10.7 cell L^?1) in depth, with abundance inversely related to tidal currents. The functional structure of the phytoplankton community measured by functional diversity (FD), varied seasonally in and across a gradient of tidal energy. A core community, mainly represented by flagellates and dinoflagellates, occurred in all observations and was highly functional (high FD), exploiting a variety of habitats. The chain‐forming diatoms were associated with high tidal energy, and occurred in higher densities during summer. Phytoplankton cell size, cell shape, and the ability to form colonies are extremely plastic traits that can be regulated by the environment, however, isolated tychopelagic diatoms were present in the study area across all seasons, with higher contributions in autumn and winter, reflecting the shallow characteristic of this system. During the winter, an exposed sandbar was formed, and the lack of connection with the ocean resulted in an abundance of riverine and brackish water taxa. In this near‐pristine estuary the densities and occurrences of HAB phytoplankton are low. Trait‐based analyses add information about community structure, which can be impacted by anthropogenic actions in urbanized coastal systems. Thus the information provided by this study regarding phytoplankton functional diversity and its relation to nutrients and hydrography in Barra Grande Estuary can be applied as a baseline model for the development of public policies.  相似文献   

Editorial     

Tijmen Jan Moser 《Geophysical Prospecting》2010,58(2):155-156

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Diffraction imaging in depth   总被引：3，自引：0，他引：3  

T.J. Moser  C.B. Howard 《Geophysical Prospecting》2008,56(5):627-641

High resolution imaging is of great value to an interpreter, for instance to enable identification of small scale faults, and to locate formation pinch-out positions. Standard approaches to obtain high-resolution information, such as coherency analysis and structure-oriented filters, derive attributes from stacked, migrated images. Since they are image-driven, these techniques are sensitive to artifacts due to an inadequate migration velocity; in fact the attribute derivation is not based on the physics of wave propagation. Diffracted waves on the other hand have been recognized as physically reliable carriers of high- or even super-resolution structural information. However, high-resolution information, encoded in diffractions, is generally lost during the conventional processing sequence, indeed migration kernels in current migration algorithms are biased against diffractions. We propose here methods for a diffraction-based, data-oriented approach to image resolution. We also demonstrate the different behaviour of diffractions compared to specular reflections and how this can be leveraged to assess characteristics of subsurface features. In this way a rough surface such as a fault plane or unconformity may be distinguishable on a diffraction image and not on a traditional reflection image.
We outline some characteristic properties of diffractions and diffraction imaging, and present two novel approaches to diffraction imaging in the depth domain. The first technique is based on reflection focusing in the depth domain and subsequent filtering of reflections from prestack data. The second technique modifies the migration kernel and consists of a reverse application of stationary-phase migration to suppress contributions from specular reflections to the diffraction image. Both techniques are proposed as a complement to conventional full-wave pre-stack depth migration, and both assume the existence of an accurate migration velocity.  相似文献   

Introduction          下载免费PDF全文

Tijmen Jan Moser 《Geophysical Prospecting》2017,65(1):5-6

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Sayh al Uhaymir 094: A new martian meteorite from the Oman desert     

E. Gnos  B. Hofmann  I. A. Franchi  A. Al-Kathiri  M. Huser  L. Moser 《Meteoritics & planetary science》2002,37(6):835-854

Abstract— Sayhal Uhaymir (SaU) 094 is a 223.3 g, partially crusted, strongly to very strongly shocked melanocratic olivine-porphyric rock of the shergottite group showing a microgabbroic texture. The rock consists of pyroxene (52.0–58.2 vol%)—dominantly prismatic pigeonite (En_60–68Fs_20–27Wo^7–9) associated with minor augite (En_46–49Fs_15–16Wo_28–31)—brown (shock-oxidized) olivine (Fo_65–69; 22.1–31%), completely isotropic interstitial plagioclase glass (maskelynite; An_50–64Or_0.3-0.9; 8.6–13.0%), chromite and titanian magnesian chromite (0.9-1.0%), traces of ilmenite (Ilm_80–86), pyrrhotite (Fe_92–100; 0.1-0.2%), merrillite (<<0.1%), and pockets (4.8-6.7%) consisting of green basaltic to basaltic andesitic shock glass that is partially devitrified into a brown to black product along boundaries with the primary minerals. The average maximum dimensions of minerals are: olivine (1.5 mm), pyroxene (0.3 mm) and maskelynite (0.3 mm). Primary melt inclusions in olivine and chromite are common and account for 0.1-0.6% of the rock. X-ray tomography revealed that the specimen contains ˜0.4 vol% of shock-melt associated vesicles, up to 3 mm in size, which show a preferred orientation. Fluidization of the maskelynite, melting and recrystallization of pyroxene, olivine and pyrrhotite indicate shock stage S6. Minor terrestrial weathering resulted in calcite-veining and minor oxidation of sulfides. The meteorite is interpreted as paired with SaU 005/008/051. The modal composition is similar to Dar al Gani 476/489/670/735/876, with the exception that neither mesostasis nor titanomagnetite nor apatite are present and that all phases show little zonation. The restricted mineral composition, predominance of chromite among the oxides, and abundance of olivine indicate affinities to the lherzolitic shergottites.  相似文献   

U-Pb zircon systematics at Gruinard Bay, northwest Scotland: implications for the early orogenic evolution of the Lewisian complex     

Fernando Corfu  Alan Crane  Desmond Moser  Graeme Rogers 《Contributions to Mineralogy and Petrology》1998,133(4):329-345

The Gruinard Bay area of the mainland Lewisian complex comprises a metamorphosed suite of Archaean trondhjemites and minor granites enclosing remnants of older tonalitic gneiss and mafic to ultramafic enclaves. The U-Pb zircon dating yields ages of 2731 ±14 Ma and 2728 ±2 Ma for two trondhjemite and 2732 ±4 Ma for one granite sample, also revealing the presence of large amounts of inherited xenocrystic zircons. Although the region has been pervasively overprinted by retrogressive events in amphibolite to greenschist facies, the textural relations between biotite, hornblende, quartz and titaniferous minerals indicate that these minerals are pseudomorphs of pyroxene and high-Ti amphibole formed in hornblende-granulite facies. Structural relations link this metamorphism to a steep northeast-trending fabric coeval with the intrusion of the trondhjemites, dated at 2730 Ma. Dating of zircon in amphibolite and tonalite enclaves yields complex internal isotopic relations with apparent ages ranging from 2825 to 2740 Ma. This age range reflects new growth during the 2730 Ma metamorphic/metasomatic events, superimposed on older zircon phases which include combinations of xenocrystic cores, and magmatic and/or metamorphic growth phases whose mode of formation cannot clearly be resolved by imaging techniques (e.g. cathodoluminescence) alone. A pegmatitic vein that escaped the D₃ strain and related isotopic disturbances yields a precise age of 2792 ±2 Ma, which constrains to some degree the earliest orogenic events in the area. Age relationships displayed in the central block at Scourie–Badcall, and in the Gruinard Bay area indicate that petrogenetic events in both areas were comparable about 2800 Ma and that both areas underwent trondhjemitic magmatism about 2730 Ma. In contrast, at Gruinard Bay there is no isotopic evidence for a period of high-grade metamorphism and magmatism at 2490–2480 Ma that drastically affected the Scourie block indicating that at this stage the two regions occupied different levels of the crust. Received: 23 October 1997 / Accepted: 20 July 1998  相似文献   

Influence of allochthonous organic matter on bacterioplankton biomass and activity in a eutrophic,sub-tropical estuary     

José Juan Barrera-Alba  Sônia Maria Flores Gianesella  Gleyci Aparecida Oliveira Moser  Flávia Marisa Prado Saldanha-Corrêa 《Estuarine, Coastal and Shelf Science》2009

Heterotrophic bacterial and phytoplankton biomass, production, specific growth rates, and growth efficiencies were studied in the Northern region of the Cananéia–Iguape estuarine system, which has recently experienced an intense eutrophication due to anthropogenic causes. Two surveys were carried out during spring and neap tide periods of the dry season of 2005 and the rainy season of 2006. This region receives large freshwater inputs with organic seston and phosphate concentrations that reach as high as 1.0 mg l⁻¹ and 20.0 μM, respectively. Strong decreasing gradients of seston and dissolved inorganic nutrients were observed from the river/estuary boundary to the estuary/coastal interface. Gradients were also observed in phytoplankton and bacterial production rates. The production rates of phytoplankton were 5.6-fold higher (mean 8.5 μg C l⁻¹ h⁻¹) during the dry season. Primary production rates (PP) positively correlated with salinity and euphotic depth, indicating that phytoplankton productivity was light-limited. On the other hand, bacterial biomass (BB) and production rates (BP) were 1.9- and 3.7-fold higher, respectively, during the rainy season, with mean values of up to 40.4 μg C l⁻¹ and 7.9 μg C l⁻¹ h⁻¹, respectively. Despite such a high BP, bacterial abundance remained <2 × 10⁶ cells ml⁻¹, indicating that bacterial production and removal were coupled. Mean specific growth rates ranged between 0.9 and 5.5 d⁻¹. BP was inversely correlated with salinity and positively correlated with temperature, organic matter, exopolymer particles, and particulate-attached bacteria; this last accounted for as much as 89.6% of the total abundance. During the rainy season, BP was generally much higher than PP, and values of BP/PP > 20 were registered during high freshwater input, suggesting that under these conditions, bacterial activity was predominantly supported by allochthonous inputs of organic carbon. In addition, BB probably represented the main pathway for the synthesis of high-quality (low C:N) biomass that may have been available to the heterotrophic components of the plankton food web, particularly nanoheterotrophs.  相似文献   

Integrating the effects of flood experience on risk perception with responses to changing climate risk     

Judy Lawrence  Dorothee Quade  Julia Becker 《Natural Hazards》2014,74(3):1773-1794

Flood management decision-makers face significant challenges as the climate changes. The perceptions of those affected by floods are critical to the successful implementation of adaptation responses; risk perceptions are affected by how information is communicated and, in turn, perceptions influence expectations on flood risk managers to respond. The links between flood experience, risk perception, and responses by individual households were examined in the Hutt Valley, New Zealand, through a household survey, a workshop and interviews with local government practitioners. Two propositions were tested: (1) that flood experience can influence flood risk perceptions; and (2) that flood experience can stimulate increased risk reduction and adaptation actions where changing climate risk is likely. Perceptions of responsibility for flood management were also examined. The study found that previous flood experience contributes to heightened perception of risk, increased preparedness of households, greater willingness to make household-level changes, greater communication with councils, and more advocacy for spatial planning to complement existing structural protection. Flood-affected households had a stronger preference for central government and communities having flood risk responsibilities, in addition to local government. Those who lacked experience were more likely to be normalised to their prior benign experiences and thus optimistic about flood consequences. These results suggest that harnessing positive aspects of experience and communication of changing risk through engagement strategies could help shift the focus from citizens’ expectation that governments will always provide protection, to a citizen–local government–central government dialogue about the changing character of flood risk and its implications, and build a ‘risk conscious’ society in which ‘sharing and bearing’ is considered desirable.  相似文献