DOWNCURRENT DECLINE OF GRAIN SIZE AND THICKNESS OF SINGLE TURBIDITE BEDS: A SEMI-QUANTITATIVE ANALYSIS     

A. E. SCHEIDEGGER  PAUL EDWIN POTTER 《Sedimentology》1971,17(1-2):41-49

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Girvanella grabaui sp.nov.aus dem unterpermischen Chuanshan-Kalk Südchinas     

HENRY PAUL 《地质学报》1938,(Z1)

Mit 1 Abbildung Nach Abfassung des Manuskriptes meiner Arbeit über"Unterkar-bonische Kalkalgen und Calcisphaeren Deutschlands",die sich u.a.mit  相似文献   

BED THICKNESS AND GRAIN SIZE: CROSS-BEDDING     

ADRIAN E. SCHEIDEGGER  PAUL EDWIN POTTER 《Sedimentology》1967,8(1):39-44

Qualitative and quantitative observations show a general positive correlation between grain size and thickness of cross-bedded units. Greater sand-wave height correlates with greater turbulence which permits more and coarser grains to be transported. A theory is developed which qualitatively explains these relationships.  相似文献   

INSECT FOSSILS AND IRRIGATION IN MEDIEVAL GREENLAND     

EVA PANAGIOTAKOPULU  MALCOLM T. GREENWOOD  PAUL C. BUCKLAND 《Geografiska Annaler: Series A, Physical Geography》2012,94(4):531-548

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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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‘The methodological basis for fine‐resolution,multi‐proxy reconstructions of ombrotrophic peat bog surface wetness’: Reply to comments     

MATTHEW J. AMESBURY  KEITH E. BARBER  PAUL D. M. HUGHES 《Boreas: An International Journal of Quaternary Research》2011,40(2):382-383

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Gendered Work: Female Labour in Pipfruit Production in New Zealand and Chile     

BEATRIZ MANZ  PAUL SPOONLEY 《New Zealand geographer》2001,57(1):8-15

This article seeks to contribute to the literature on female labour in the pipfruit industry in New Zealand and Chile. As added workers seeking to supplement household incomes by casualised, seasonal employment, these female workers are significant contributors to what are often declining household incomes, given changes in production and the labour market of the 1990s. But this enhanced role continues to exist alongside normative expectations about domestic roles and responsibilities. This research reports on a survey that was completed by female workers in both Chile and New Zealand. While there are differences in the respective labour markets of the two countries concerned, the role of women in balancing employment and domestic responsibilities is characteristic of both situations. It is the intersection between normative expectations and participation in casual/seasonal labour in the two research sites that is the focus of this article.  相似文献   

Mid-Cretaceous basin margin carbonates, east-central Mexico     

PAUL ENOS  BRYAN P. STEPHENS 《Sedimentology》1993,40(3):539-556

Isolated, high relief carbonate platforms developed in the intracratonic basin of east-central Mexico during Albian-Cenomanian time. Relief on the platforms was of the order of 1000 m and slopes were as steep as 20–43°. Basin-margin debris aprons adjacent to the platforms comprise the Tamabra Formation. In the Sierra Madre Oriental, at the eastern margin of the Valles-San Luis Potosi Platform, an exceptionally thick (1380m) progradational basin to platform sequence of the Tamabra Formation can be divided into six lithological units. Basinal carbonate deposition that preceded deposition of the Tamabra Formation was emphatically punctuated by an allochthonous reef block 1 km long by 0·5 km wide with a stratigraphic thickness of 95 m. It is encased in Tamabra Formation unit A, approximately 360 m of peloidal-skeletal wackestone and lithoclastic-skeletal packstone that includes some graded beds. Unit B is 73 m of massive dolomite with sparse skeletal fragments and intraclasts. Unit C, 114m thick, consists of structureless skeletal wackestone passing upward into graded skeletal packstone. Interlaminated lime mudstone and fine grained bioclastic packstone with prominent horizontal burrows are interspersed near the top. Unit D is 126 m of breccia with finely interbedded skeletal grainstone and burrowed or laminated mudstone. The breccias contain a spectrum of platform-derived lithoclasts and basinal intraclasts, up to 10 m in size. The breccias are typically grain supported (rudstone) with a matrix of lightly to completely dolomitized mudstone or skeletal debris. Beds are up to several metres thick. Unit E is 206 m of massive, sucrosic dolomite that replaced breccias. Unit F is approximately 500 m of thick bedded to massive skeletal packstone with abundant rudists and a few mudstone intraclasts. Metre scale laminated lime mudstone beds are interspersed. The section is capped by El Abra Formation platform margin limestone, consisting of massive beds of caprinid packstone and grainstone with many whole valves. Depositional processes within this sequence shift from basinal pelagic or peri-platform sedimentation to distal, platform-derived, muddy turbidity currents with a large slump block (Unit A); through more proximal (coarser and cleaner) turbidity currents (Unit B?, C); to debris flows incorporating platform margin and slope debris (Units D, E). Finally, a talus of coarse, reef-derived bioclasts (Unit F) accumulated as the platform margin prograded over the slope sequence. Interspersed basinal deposits evolved gradually from largely pelagic to include influxes of dilute turbidity currents. Units containing turbidites with platform-derived bioclasts reflect flooding of the adjacent platform. Breccia blocks and lithoclasts were probably generated by erosion and collapse of the platform during lowstands. Laminated, black, pelagic carbonates, locally cherty, are interbedded with both breccias and turbidites. At least those interbedded with turbidites may have been deposited within an expanded mid-water oxygen minimum zone during relative highstands of sea level. They are in part coeval with mid-Cretaceous black shales of the Atlantic Ocean.  相似文献   

Editorial     

MAURICE TUCKER  PAUL BRIDGES  JOHN BRIDGE 《Sedimentology》1983,30(1):1-1

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