Southern Waters          下载免费PDF全文

Lisa Davis 《Geographical review》2016,106(2):e38-e40

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Interseismic deformation in south-central Tibet from InSAR and GPS data     

Hua Wang  Tim J. Wright  Jing Liu Zeng  Lincai Peng 《《地质学报》英文版》2018,92(Z1):148-148

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Geochronology,stratigraphy and geochemistry of Cambro-Ordovician,Silurian and Devonian volcanic rocks of the Saxothuringian Zone in NE Bavaria (Germany)—new constraints for Gondwana break up and ocean–island magmatism     

Höhn  Stefan  Koglin  Nikola  Klopf  Lisa  Schüssler  Ulrich  Tragelehn  Harald  Frimmel  Hartwig E.  Zeh  Armin  Brätz  Helene 《International Journal of Earth Sciences》2018,107(1):359-377

International Journal of Earth Sciences - Stratigraphically well-defined volcanic rocks in Palaeozoic volcano-sedimentary units of the Frankenwald area (Saxothuringian Zone, Variscan Orogen) were...  相似文献   

Elucidating hydrological complexity and climate-influenced diagenesis during the early Carboniferous of South Wales     

N.J. Hogancamp  V.P. Wright 《Proceedings of the Geologists' Association. Geologists' Association》2021,132(1):93-101

A revised age provided by conodonts from the Gilwern Oolite of the Clydach area of South Wales allows a clearer understanding of the palaeohydrology, palaeoclimatic history and diagenesis of previously correlated oolitic units. Earlier uncertainty over the apparent sub-regional differences in climate during the early Visean (Chadian—Arundian) lowstand is resolved. Previously a humid interval evidenced by prominent palaeo-epikarst capping the Gilwern Oolite along the northern outcrops of the South Wales synclinorium, was not recognized in what were regarded as correlative outcrops in the Chadian Gully Oolite in the southern part of the synclinorium. Conodont dating now shows that the Gilwern Oolite is much older (Courceyan) than the Chadian Gully Oolite, and during the prolonged exposure of the former there was an interval of weathering under a humid climate. This also explains the contrast between the diagenesis seen between the Gilwern and Gully oolites, which are no longer seen as correlatives.  相似文献   

Pyrite formation and the drowning of a palaeosol     

V. Paul Wright 《Geological Journal》1986,21(2):139-149

Palaeosols may be modified in a variety of ways during burial diagenesis but significant alteration can take place during the earliest phases of burial caused by rising groundwaters. A calcrete palaeosol, the Heatherslade Geosol, from the Lower Carboniferous of South Wales, contains abundant pyrite which overprinted the original soil fabrics. The pyrite is interpreted as the product of anaerobic conditions caused by drowning during the early stages of a marine transgression. Unusual diamond-shaped forms of pyrite occur which possibly represent pseudomorphs after gypsum.  相似文献   

The Public Is Intellectual     

Willie Jamaal Wright 《The Professional geographer》2019,71(1):172-178

This article is a discussion and critique of public intellectualism in the present. Rather than reify a self-aggrandized form of public intellectualism within academia that centers individualized intellectual development and that encourages a greater flow of findings outward to communities, I highlight black women public intellectuals who have used their skills, talents, and station within the university and society in novel ways. Moreover, I suggest that scholars take seriously the questions, research methods, and analyses emerging from the general public, particularly from within communal and political organizations. These encouragements are illustrated by highlighting three political education workshops that have been developed across the United States.  相似文献   

Revised recommended methods for analyzing crater size-frequency distributions          下载免费PDF全文

Stuart J. Robbins  Jamie D. Riggs  Brian P. Weaver  Edward B. Bierhaus  Clark R. Chapman  Michelle R. Kirchoff  Kelsi N. Singer  Lisa R. Gaddis 《Meteoritics & planetary science》2018,53(4):891-931

Impact crater populations help us to understand solar system dynamics, planetary surface histories, and surface modification processes. A single previous effort to standardize how crater data are displayed in graphs, tables, and archives was in a 1978 NASA report by the Crater Analysis Techniques Working Group, published in 1979 in Icarus. The report had a significant lasting effect, but later decades brought major advances in statistical and computer sciences while the crater field has remained fairly stagnant. In this new work, we revisit the fundamental techniques for displaying and analyzing crater population data and demonstrate better statistical methods that can be used. Specifically, we address (1) how crater size-frequency distributions (SFDs) are constructed, (2) how error bars are assigned to SFDs, and (3) how SFDs are fit to power-laws and other models. We show how the new methods yield results similar to those of previous techniques in that the SFDs have familiar shapes but better account for multiple sources of uncertainty. We also recommend graphic, display, and archiving methods that reflect computers’ capabilities and fulfill NASA's current requirements for Data Management Plans.  相似文献   

Correlation between petrography,NAA, and ICP analyses: Application to early bronze Egyptian pottery from Canaan     

Naomi Porat  Joseph Yellin  Lisa Heller-Kallai  Ludwik Halicz 《Geoarchaeology》1991,6(2):133-149

Under favorable circumstances petrographic studies supported by chemical analysis using inductively coupled plasma (ICP) suffice to establish the provenience of pottery. A case in point is Egyptian-style pottery of Early Bronze Age found in Canaan. The pottery was divided into three groups according to four criteria determined by thin section analysis supplemented by X-ray diffraction: sorting and volume of silt-sized quartz, heavy minerals, the amount of carbonates in the matrix, and the firing temperature. Chemical analyses confirmed the classification. The source materials inferred for the three groups are Nile muds, Egyptian marly sediments, and local loess. Although the chemical analyses obtained by ICP and neutron activation analysis (NAA) were compatible, the existing database for NAA cannot be used indiscriminately. However, for provenience studies based on mineralogical and petrographic data, knowledge of the geology of the potential source areas can replace an extensive database.  相似文献   

Cryptic exposure horizons in the Carboniferous Limestone of Portishead,Avon     

T. J. Faulkner  V. P. Wright  C. Peeters  L. Garvie 《Geological Journal》1990,25(1):1-17

Two unusual subaerial exposure horizons containing fibrous columnar calcite crystals are described from the (early Chadian) Lower Carboniferous of Portishead, near Bristol in southwest Britain. The lower horizon overlies the Courceyan Black Rock Limestone (mid-ramp facies) and is separated from the upper horizon by the Sub-Oolite Bed and is overlain by the Chadian Gully Oolite (both are inner ramp deposits). Regionally the Portishead Palaeosol Beds are interpreted as forming part of extensive emergent surfaces which developed along the southern margin of the Welsh–Brabant Massif. They correlate with similar subaerial exposure horizons in Belgium and southern Germany, and may be the product of a proposed major eustatic sea level fall at the end of the Courceyan.  相似文献   

Meio-epifaunal wood colonization in the vicinity of methane seeps     

Adriana Gracia C.  Lisa A. Levin  Sven Zea 《Marine Ecology》2020,41(1):e12573

In deep-sea environments, plant remains of several origins are found, including branches, twigs, leaves, and wood pieces, among others. As most of the deep-sea bottoms are oligotrophic and nutrient-limited, plant remains provide an oasis of localized organic enrichment and a substrate for colonization. Sunken wood was suggested to play an important evolutionary role in the diversification of chemosynthetic ecosystems, possibly representing stepping stones for the colonization between vent and seep ecosystems. In order to understand colonization processes of the Pacific Costa Rican meio-epifaunal assemblages associated with sunken wood, a field experiment was conducted on Mound 12 (8°55.778′N, 84°18.730′W) at ~1,000 m water depth. Woodblocks were placed in four different habitats (Mussel beds, tube worms, near mussel beds, rubble bottoms), and different local environmental conditions (seepage-active and seepage-inactive sites). Seven experimental Douglas fir woodblocks (each 1,047 cm² in surface area) were deployed from the R/V Atlantis using the manned submersible Alvin in February 2009 and recovered after 10.5 months in January 2010. Sample processing and analyses led to a data set of abundance (total 9,951 individuals) and spatial distribution of nine meio-epifaunal higher taxa/groups. Meio-epifaunal densities on individual woodblocks ranged from 3 to 26 ind.10 cm². Copepods accounted for the highest abundances (75.1%), followed by nauplii larvae (11.7%) and nematodes (9.8%). The maximum number of individuals (26.3 ind.10 cm⁻²) was found in blocks placed in seepage-inactive areas (near active mussel beds) in contrast to 2.9 ind.10 cm⁻² in active areas (within a mussel bed). A hierarchical cluster analysis grouped blocks according to seepage activity and not to habitat, but tests of similarity showed no significant differences in higher taxon composition and abundances, probably owing either to substrate homogeneity or low sample size. Copepods were the most abundant representatives, suggesting that this group is one of the most successful in colonizing in the early stage of succession, in this case while hardwood substrates are not yet decomposed or bored by bivalves.  相似文献