Exhumed hydrocarbon traps on the North Atlantic margin: Stratigraphy,palaeontology, provenance and bitumen distribution,an integrated approach     

Steven D. Andrews  Audrey Decou  Bill Braham  Simon R. A. Kelly  Paula Robinson  Andrew C. Morton  John E. A. Marshall  Fiona Hyden 《Basin Research》2020,32(5):1213-1233

Previous work has demonstrated the presence of a number of exhumed hydrocarbon traps in central East Greenland. Re-evaluation of the stratigraphy alongside detailed investigation of the occurrence of bitumen within the Mols Bjerge and Laplace Bjerg exhumed hydrocarbon traps provides new perspectives on these structures, as well as the petroleum geology of East Greenland and the wider North Atlantic. Sedimentological and stratigraphic studies, augmented with palynological and provenance investigations, have constrained the dating and correlation of the strata exposed in the Mols Bjerge and Laplace Bjerg. Petrographic analysis, alongside analysis of the bitumen identified, has highlighted a much wider distribution of hydrocarbon than previously recognized. It was previously considered that Jurassic strata formed the main reservoir interval within the Mols Bjerge and Laplace Bjerg exhumed hydrocarbon traps. It is shown here that the reservoir intervals in the Laplace Bjerg trap lie within the Late Triassic Ørsted Dal and Vega Sund members, which contain up to 18% pyrobitumen and were previously misidentified as Jurassic. The Jurassic Bristol Elv Formation is the most extensively bitumen stained unit in the Mols Bjerge trap. However, occurrences of pyrobitumen (up to 3%) are recorded throughout the Triassic stratigraphy, including the Early Triassic Wordie Creek Formation. Faults, thick calcrete development and regionally continuous mudstone units play an important role in compartmentalizing the palaeohydrocarbon accumulations.  相似文献   

Development of Atlantic cod (Gadus morhua) exposed to produced water during early life stages: Effects on embryos, larvae, and juvenile fish     

Sonnich Meier  H. Craig Morton  Gunnar Nyhammer  Bjrn Einar Grsvik  Valeri Makhotin  Audrey Geffen  Stepan Boitsov  Karen Anita Kvestad  Anneli Bohne-Kjersem  Anders Goksyr  Arild Folkvord  Jarle Klungsyr  Asbjrn Svardal 《Marine environmental research》2010,70(5):383-394

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The formation and aqueous alteration of CM2 chondrites and their relationship to CO3 chondrites: A fresh isotopic (O,Cd, Cr,Si, Te,Ti, and Zn) perspective from the Winchcombe CM2 fall     

R. C. Greenwood  R. Findlay  R. Martins  R. C. J. Steele  K. M. M. Shaw  E. Morton  P. S. Savage  M. E. Murphy  M. Rehkämper  I. A. Franchi  T. Elliott  M. D. Suttle  A. J. King  M. Anand  J. Malley  K. T. Howard  X. Zhao  D. Johnson  M.-C. Liu  K. A. McCain  N. R. Stephen 《Meteoritics & planetary science》2024,59(5):1170-1193

As part of an integrated consortium study, we have undertaken O, Cd, Cr, Si, Te, Ti, and Zn whole rock isotopic measurements of the Winchcombe CM2 meteorite. δ⁶⁶Zn values determined for two Winchcombe aliquots are +0.29 ± 0.05‰ (2SD) and +0.45 ± 0.05‰ (2SD). The difference between these analyses likely reflects sample heterogeneity. Zn isotope compositions for Winchcombe show excellent agreement with published CM2 data. δ¹¹⁴Cd for a single Winchcombe aliquot is +0.29 ± 0.04‰ (2SD), which is close to a previous result for Murchison. δ¹³⁰Te values for three aliquots gave indistinguishable results, with a mean value of +0.62 ± 0.01‰ (2SD) and are essentially identical to published values for CM2s. ε⁵³Cr and ε⁵⁴Cr for Winchcombe are 0.319 ± 0.029 (2SE) and 0.775 ± 0.067 (2SE), respectively. Based on its Cr isotopic composition, Winchcombe plots close to other CM2 chondrites. ε⁵⁰Ti and ε⁴⁶Ti values for Winchcombe are 3.21 ± 0.09 (2SE) and 0.46 ± 0.08 (2SE), respectively, and are in line with recently published data for CM2s. The δ³⁰Si composition of Winchcombe is −0.50 ± 0.06‰ (2SD, n = 11) and is essentially indistinguishable from measurements obtained on other CM2 chondrites. In conformity with petrographic observations, oxygen isotope analyses of both bulk and micromilled fractions from Winchcombe clearly demonstrate that its parent body experienced extensive aqueous alteration. The style of alteration exhibited by Winchcombe is consistent with relatively closed system processes. Analysis of different fractions within Winchcombe broadly support the view that, while different lithologies within an individual CM2 meteorite can be highly variable, each meteorite is characterized by a predominant alteration type. Mixing of different lithologies within a regolith environment to form cataclastic matrix is supported by oxygen isotope analysis of micromilled fractions from Winchcombe. Previously unpublished bulk oxygen isotope data for 12 CM2 chondrites, when combined with published data, define a well-constrained regression line with a slope of 0.77. Winchcombe analyses define a more limited linear trend at the isotopically heavy, more aqueously altered, end of the slope 0.77 CM2 array. The CM2 slope 0.77 array intersects the oxygen isotope field of CO3 falls, indicating that the unaltered precursor material to the CMs was essentially identical in oxygen isotope composition to the CO3 falls. Our data are consistent with earlier suggestions that the main differences between the CO3s and CM2s reflect differing amounts of water ice that co-accreted into their respective parent bodies, being high in the case of CM2s and low in the case of CO3s. The small difference in Si isotope compositions between the CM and CO meteorites can be explained by different proportions of matrix versus refractory silicates. CMs and COs may also be indistinguishable with respect to Ti and Cr isotopes; however, further analysis is required to test this possibility. The close relationship between CO3 and CM2 chondrites revealed by our data supports the emerging view that the snow line within protoplanetary disks marks an important zone of planetesimal accretion.  相似文献   

Evolution of provenance in the NE Atlantic rift: The Early–Middle Jurassic succession in the Heidrun Field,Halten Terrace,offshore Mid-Norway     

Andrew Morton  Claire Hallsworth  Dominic Strogen  Andrew Whitham  Mark Fanning 《Marine and Petroleum Geology》2009

An integrated provenance study using provenance-sensitive heavy mineral ratios, mineral chemistry and U/Pb dating of detrital zircons has revealed significant changes in sediment provenance during deposition of the Early to Middle Jurassic succession in the Heidrun Field, offshore Mid-Norway. The variations result from the interplay of two source regions, one of which was located on the Norwegian landmass and the other on the conjugate East Greenland margin. Sediment sourced from central East Greenland is distinguished by high garnet:zircon, high rutile:zircon, low chrome spinel:zircon, garnet assemblages rich in low-Ca, high-Mg varieties, and zircon populations that include an Archean group, a diverse range of Early–Middle Proterozoic grains, and an Early Paleozoic group. These features indicate derivation from a high-grade (granulite facies) metasedimentary terrain together with Archean basement and Early Paleozoic granitoids. Norwegian-sourced sandstones differ by having lower garnet:zircon and rutile:zircon, variable chrome spinel:zircon, garnet assemblages scarce in low-Ca, high-Mg varieties, and zircon populations that lack an Archean group. Derivation from the Caledonian Nappe Domain, comprising metasediments (predominantly at amphibolite facies), ophiolites and Early Paleozoic granitoids, is indicated. Initially, during deposition of the non-marine lower part of the Åre Formation (Hettangian–Sinemurian), sediment was fed from the west, but in the upper (tidally influenced) part of the Åre Formation (Sinemurian–Pliensbachian), Norwegian-sourced material appears. Greenland-derived material disappears in the subsequent Tilje Formation (Pliensbachian), with the Tilje and subsequent Ror and Ile Formations (Toarcian–Aalenian) being predominantly sourced from the east. The regional regression at the base of the Garn Formation (Bajocian) was accompanied by a switch in provenance, with Greenland-derived material replacing sediment sourced from Norway. Variations in mineralogy offer a framework for correlation on both local and sub-regional scales.  相似文献   

At last, a trawling ban for Hong Kong's inshore waters     

Morton B 《Marine pollution bulletin》2011,62(6):1153-1154

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A fresh framework for the ecology of arid Australia     

S.R. Morton  D.M. Stafford SmithC.R. Dickman  D.L. DunkerleyM.H. Friedel  R.R.J. McAllisterJ.R.W. Reid  D.A. RoshierM.A. Smith  F.J. WalshG.M. Wardle  I.W. Watson  M. Westoby 《Journal of Arid Environments》2011,75(4):313-329

A revised set of propositions about ecology in arid Australia is presented, based on research literature since publication of Stafford Smith and Morton (1990). Fourteen propositions distil our argument that most features of the Australian deserts are explicable in terms of two dominant physical and climatic elements: rainfall variability, leading to extended droughts and occasional flooding rains; and widespread nutrient poverty. Different landscapes within the arid zone show these features to varying degrees, and so it is important to think about different places separately when considering our propositions. Plant life-histories strongly reflect temporal patterns of soil moisture; because Australian deserts receive more variable rainfall than most others, there is a distinctive spectrum of life-histories. Low levels of phosphorus (together with abundant soil moisture on irregular occasions) favour plants producing a relative excess of carbohydrate (C). In turn, C-rich plant products sometimes lead to fire-prone ecosystems, assemblages dominated by consumers of sap and other C-based products, and abundant detritivores (particularly termites). Fluctuations in production due to variable rainfall provide openings for consumers with opportunistic life-histories, including inhabitants of extensive but ephemeral rivers and lakes. Most consumer species exhibit some dietary flexibility or utilise more dependable resources; these strategies give rise to greater stability in species dynamics and composition of assemblages than might first be imagined under the variable rainfall regime. Aboriginal people have had long-standing ecological influence as they accessed resources. For each proposition we suggest the extent to which it is ‘different’, ‘accentuated’ or ‘universal’ in comparison with other deserts of the world, recognising that this categorisation is in need of critical testing. Further tests of each proposition are also suggested to fill the many gaps that still exist in our knowledge of the structure and functioning of Australia’s deserts.  相似文献   

Analysis of population dynamics using satellite remote sensing and US census data     

Thomas Alan Morton 《国际地球制图》2013,28(2):143-163

The population dynamics from 1991 to 2006 for the seven-county Twin Cities Metropolitan Area (TCMA), Minnesota, USA, was analysed in this study. Per cent impervious surface areas (%ISA) for 1991, 1999 and 2006 were derived from Landsat Thematic Mapper (TM) images and were modified using two different masking methods. The modified %ISA images of 1991 and 1999 were correlated with 1990 and 2000 census block group data of the ‘two highly developed counties’, ‘five suburban counties’ and ‘all seven counties.’ Populations of both years were then modelled, assessed and compared. Next, the statistical models based on the 1999 %ISA and 2000 census data were applied to the 2006 residential %ISA image to estimate the 2006 population. These 2006 estimates were compared with census county-level population projections for 2006. In comparison to Method A, which uses ‘adjusted %ISA images’ by masking out highway centrelines and areas that have greater than 75% imperviousness, Method B based on ‘pure residential %ISA image’ has higher coefficient of determination (R ²) and much lower, consistent mean absolute relative errors (MARE). For both methods, the strongest R ² and lowest MARE values between modelled population density and true density were found in the five-county model, followed by the seven-county model. The two-county model ranks last in terms of model performance for both years. In general, populations for the two highly developed counties were underestimated whereas the opposite was true for the five suburban counties. Population was most accurately estimated based on data from counties with the same or similar characteristics. By comparing the 1990/1991 and 1999/2000 models, we also found that the rate of population density per unit of impervious surface declined from 1991 to 1999. High accuracy was achieved when applying the 1999/2000 model to predict the 2006 population, suggesting that the relationship between per cent imperviousness and population density were relatively stable between 1999 and 2006.  相似文献   

A USRP2-based reconfigurable multi-constellation multi-frequency GNSS software receiver front end     

Senlin Peng  Yu Morton 《GPS Solutions》2013,17(1):89-102

We present a multi-constellation multi-band GNSS software receiver front end based on USRP2, a general purpose radio platform. When integrated with appropriate daughter boards, the USRP2 can be used to collect raw intermediate frequency (IF) data covering the entire GNSS family of signals. In this study, C++ class-based software receiver processing functions were developed to process the IF data for GPS L1, L2C, and L5 and GLONASS L1 and L2 signals collected by the USRP2 front end. The front end performance is evaluated against the outputs of a high end custom front end driven by the same local oscillator and two commercial receivers, all using the same real signal sources. The results show that for GPS signals, the USRP2 front end typically generates carrier-to-noise ratio (C/N ₀) at 1–3 and 1–2 dB below that of the high end front end and a NovAtel receiver, respectively. For GLONASS signals, the USRP2 C/N ₀ outputs are comparable to those of a Septentrio receiver. The carrier phase noise from the USRP2 outputs is similar to those of the benchmarking devices. These results demonstrate that the USRP2 is a suitable front end for applications, such as ionosphere scintillation studies.  相似文献   

Detecting outliers in irregularly distributed spatial data sets by locally adaptive and robust statistical analysis and GIS     

Hongxing Liu  Kenneth C. Jezek  Morton E. O'Kelly 《International journal of geographical information science》2013,27(8):721-741

In this paper, we propose a new method for detecting outliers in an irregularly distributed spatial data set. Our method has two desirable properties. First, it is functionally effective due to the introduction of sensitive outlier indices and locally adaptive and robust statistical criteria. Second, it is computationally efficient because of the use of super-block based spatial data sorting and searching scheme. Our method has been implemented using the C programming language and integrated with the Arc/Info GIS system. The integration leads to a powerful exploratory data analysis tool for checking and analysing anomalous values in a GIS environment. Local outliers can be automatically labeled with our method, subject to some user-defined parameters. Outliers represent anomalous or suspicious values in a statistical sense, which may not necessarily be erroneous values. Instead of being simply discarded, statistical outliers should be investigated further using prior qualitative knowledge or in association with other GIS data layers.  相似文献   

Rare earth elements of the Altar Desert dune and coastal sands, Northwestern Mexico     

Juan Jos Kasper-Zubillaga  Beatriz Acevedo-Vargas  Ofelia Morton Bermea  Glicinia Ortiz Zamora 《Chemie der Erde / Geochemistry》2008,68(1):45-59

Twenty-one surficial sand samples from the Altar Desert coastal and desert dune systems were analysed for rare earth elements (REE) content. This was done to observe the provenance signatures for four strategic dune localities near the Colorado River Delta, the El Pinacate dune fields, and the beaches of the north of the Gulf of California in the state of Sonora, Mexico. Our goals are to show which mechanisms (i.e., aeolian, marine) exert more influence on the composition of the Altar Desert dune sands. This study also shows the usefulness of REE spatial distribution to determine the relative mobility of the sand. Some sand samples from the dune systems in San Luis Río Colorado (SLRC), Golfo de Santa Clara (GSC), and Puerto Peñasco (PP) displayed dissimilar REE concentrations with respect to the rest of the sand samples from the same sites. These differences can be related to short aeolian transport distance in the sands with high REE concentrations and long aeolian transport distance in the sands with low REE concentrations. Besides, high REE concentration in the sands might be due to their closeness to the Colorado River Delta sediments and to recycled sands derived from granitic rocks. In contrast, all the sand samples from the El Pinacate (EP) site have similar REE concentration values, suggesting that the El Pinacate dune sands are influenced by more selective aeolian processes and less diverse heavy mineral content. The Altar Desert dune sands are derived from granitic sources eroded by the Colorado River. Our results also indicate that the Altar Desert dune sands are low in heavy mineral content (with the exception of Fe and Ti bearing minerals) and enriched in carbonates with phosphates (especially at the PP site) yielding poor correlations between REE and major element concentrations. The REE geographical distribution values in the Altar Desert dune sands indicate that light and heavy REE concentration values are related to aeolian transport, maturity of the sands, their low weathering rates, proximity of the source rocks, and the biogenic debris input from beach sands into the dune.  相似文献