Late Devensian and Holocene depositional environments associated with the coversand around Caistor, north Lincolnshire, UK     

MARK D. BATEMAN  JULIAN B. MURTON  WILLIAM CROWE 《Boreas: An International Journal of Quaternary Research》2000,29(1):1-15

Sand deposits described at three sites near Caistor, north Lincolnshire (UK), provide a record of Late Devensian (Late Weichselian) to Holocene palaeoenvironments at the western margin of the European sand belt. Thermoluminescence (TL) and radiocarbon analyses provide for the first time a chronological framework for the demise of proglacial Lake Humber and the onset of coversand deposition. The reconstructed palaeoenvironmental history suggests that proglacial Lake Humber had receded from its initial high-level stand before c. 18 ka, exposing the lake floor to periglacial conditions marked by the development of thermal contraction cracks. In the period between c. 18 and 14 ka, sand-depositional processes changed from dominantly fluvial to aeolian. The fluvial activity was possibly a consequence of ameliorating winter climates between c. 17 and 16 ka. The aeolian coversand deposition in this period has not been previously recognized in Britain and correlates with the Older Coversand II and Younger Coversand I deposits elsewhere in the European sand belt. Peat accumulation followed during the Windermere (Bølling/Allerød) Interstadial and early part of the Loch Lomond Stadial (Younger Dryas) before regionally extensive coversand deposition took place in the later part of the Loch Lomond Stadial. This coversand correlates with the widespread Younger Coversand II deposits found both within the UK and across the European sand belt. The Holocene has been characterized by widespread stability with the development of soils on the coversand punctuated with periods of localized reworking through to the present day.  相似文献   

Three-dimensional transport and concentration of SF₆     

A. SCOTT DENNING  MARK. HOLZER  KEVIN R. GURNEY  MARTIN HEIMANN  RACHEL M. LAW  PETER J. RAYNER  INEZ Y. FUNG  SONG-MIAO FAN  SHOICHI TAGUCHI  PIERRE FRIEDLINGSTEIN  YVES BALKANSKI  JOHN TAYLOR  MANFRED MAISS  INGEBORG LEVIN 《Tellus. Series B, Chemical and physical meteorology》1999,51(2):266-297

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Aspects of the large-scale tropical atmospheric circulation     

BRIAN HOSKINS  RICHARD NEALE  MARK RODWELL  GUI-YING YANG 《地球，A辑:动力气象学与海洋学》1999,51(1):33-44

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Re‐evaluation of the Last Glacial Maximum typesite at Dimlington,UK     

MARK D. BATEMAN  PAUL C. BUCKLAND  MARTIN A. WHYTE  ROBERT A. ASHURST  CLAIRE BOULTER  EVA PANAGIOTAKOPULU 《Boreas: An International Journal of Quaternary Research》2011,40(4):573-584

Bateman, M. D., Buckland, P. C., Whyte, M. A., Ashurst, R. A., Boulter, C. & Panagiotakopulu, E. 2011: Re‐evaluation of the Last Glacial Maximum typesite at Dimlington, UK. Boreas, 10.1111/j.1502‐3885.2011.00204.x. ISSN 0300‐9483. Recent erosion has allowed re‐examination of the stratigraphy and sampling for both optically stimulated luminescence dating and palaeoecological analysis of the key sections in the Last Glacial Maximum deposits at Dimlington in East Yorkshire, England. Both stratigraphy and fossil insect evidence support a subaerial origin for laminated and cross‐bedded sediments between two diamictons previously interpreted as synchronous. The fossil biota indicates conditions similar to those of a pond on sandur in the high Arctic, with little or no vegetation cover. The existence of distinct oscillations of the ice front is indicated. The first, within the period 21.7–16.2 ka, appears coincident with climate warming, as deduced from Greenland ice‐core evidence, and is interpreted as an ice stream associated with changing flow patterns within the British–Irish Ice Sheet (BIIS). The second, dating between 16.2 and 15.5 ka, appears to coincide with a climatic cooling, although current models show that the BIIS had by this period already retreated back to ice centres. This new evidence supports the view that the eastern sector of the BIIS did not reach its maximal extent synchronously with other parts of the BIIS.  相似文献   

On the background photochemistry of tropospheric ozone     

PAUL J. CRUTZEN  MARK G. LAWRENCE  ULRICH PÖSCHL 《地球，A辑:动力气象学与海洋学》1999,51(1):123-146

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Sr, Nd, Pb and O Isotopes of Minettes from Schirmacher Oasis, East Antarctica: a Case of Mantle Metasomatism involving Subducted Continental Material   总被引：2，自引：4，他引：2  

HOCH  MARION; REHKAMPER  MARK; TOBSCHALL  HEINZ J. 《Journal of Petrology》2001,42(7):1387-1400

Numerous minette dykes intersect the Precambrian crystallinebasement of Schirmacher Oasis, East Antarctica. This study presentsnew Sr, Nd, Pb and O isotope data for 11 minette samples fromfour different dykes. The samples are characterized by relativelyhigh ⁸⁷Sr/⁸⁶Sr (0·7077–0·7134), ²⁰⁷Pb/²⁰⁴Pb(15·45–15·55) and ²⁰⁸Pb/²⁰⁴Pb (37·8–39·8),combined with low ¹⁴³Nd/¹⁴⁴Nd (  相似文献   

The planform of epeirogeny: vertical motions of Australia during the Cretaceous   总被引：1，自引：0，他引：1  

MARK Russell  MICHAEL Gurnis 《Basin Research》1994,6(2-3):63-76

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Climatic control on Quaternary fluvial sedimentology of a Fenland Basin river, England   总被引：1，自引：0，他引：1  

REBECCA M. BRIANT  MARK D. BATEMAN†  G. RUSSELL COOPE‡  PHILIP L. GIBBARD 《Sedimentology》2005,52(6):1397-1423

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Specifying the transformations within and between geographic data models     

MARK GAHEGAN 《Transactions in GIS》1996,1(2):137-152

Geographic information is acquired according to several different underlying models of geographic space. Any meaning inherent within a dataset is intrinsically connected to the model by which it was captured. A design is presented for an integrated geographic information system offering a number of distinct views onto geographic space, of varying degrees of abstraction, to support the needs of an expanded user base. An architecture for such a system is developed by an extension of the traditional three layer architecture used in database design. The movement of data from one level of abstraction to another is formalized by a series of dataset and model transformations operating between four different geographic data models. From this formalism, a functional taxonomy of GIS operations is developed.  相似文献   

One-dimensional models of groundwater flow, sediment thermal history and petroleum generation within continental rift basins   总被引：1，自引：0，他引：1  

MARK Person  DENAH Toupin†  PETER Eadington‡ 《Basin Research》1995,7(1):81-96

We investigate the effects of convective heat transfer on the thermal history of sediments and petroleum formation within continental rift basins using one-dimensional mathematical modelling. The transport equations used in this study to describe vertical groundwater flow and conductive/convective heat transfer are solved by the finite element method. Sediment thermal history is quantitatively represented using first-order rate kinetic expressions for kerogen degradation and an empirical fanning Arrhenius model for apatite fission track annealing. Petroleum generation is also represented in the model by a suite of first-order rate kinetic expressions. The analysis provides insights into how pore fluid circulation patterns are preserved in the rock record as anomalies in palaeogeothermometric data within continental rifts. Parameters varied in the numerical experiments include the ratio of conductive to convective heat transfer (thermal Peclet number; Pe) and the composition of the disseminated organic matter in the sediment (type II and III kerogen). Quantitative results indicate that vertical groundwater flow rates on the order of a mm/yr cause a change in computed vitrinite reflectance of the rocks and a shift in the depth to oil generation by as much as 3000 m. Differences in thermal gradients between recharge and discharge areas (Pe= 0.6) also change the width of the zone of oil generation by a factor of two. Even more dramatic, however, are the large changes in predicted apatite fission track length distributions and model ages between recharge and discharge areas. For example, a sediment package buried to a depth of 2400 m over 200 Myr within the groundwater recharge column had a fission track length distribution with a computed mean and standard deviation of 12.83 μm and 0.77 μm, respectively. The fission track model age for this sediment package was 209 Ma. The same sediment package in the discharge area has a distribution with a mean track length of 5.68 μm, a standard deviation of 3.37 μm, and a fission track model age of 2.6 Ma. Transient groundwater flow simulations, in which fluid circulation ceases after a period of time within the rift basin, are also presented to illustrate how disturbances in palaeogeothermometric parameters are preserved on geological time-scales. Vitrinite reflectance profiles require about 10 Myr to return to conductive conditions within groundwater recharge areas while the convective disturbances are preserved indefinitely along the discharge column, as long as further subsidence does not occur. Ancient groundwater flow systems are preserved as anomalies in computed apatite fission track model ages and distributions much longer after groundwater flow stops, relative to organic-based geothermometers. Significant differences exist in model ages between recharge (145 Ma) and discharge (90 Ma) areas 200 Myr after flow has ceased. However, calculated fission track histogram distributions are virtually identical in recharge and discharge areas after about 50 Myr. Our study suggests that ancient groundwater flow systems can be detected by comparing thermochronometric data between suspected recharge and discharge areas within continental rifts. Vitrinite reflectance profiles, observed offsets in the depth to the onset of petroleum generation, and apatite fission track annealing studies are all well suited for detecting groundwater flow systems which have been relatively long lived (10⁷ years). Apatite fission track age data are probably best suited for identifying ancient groundwater flow systems within rifts long (>200 Myr) after flow ceases.  相似文献