Sandstone mounds and associated facies sequences in some Late Precambrian and Cambro-Ordovician inshore tidal flat/lagoonal deposits     

CHRISTOPHER T. BALDWIN  HOWARD D. JOHNSON 《Sedimentology》1977,24(6):801-818

Sandstone mounds occur in some shallow marine heterolithic deposits from the Late Precambrian Stangenes Formation (N. Norway) and the Cambro-Ordovician Crozon Formation (N. W. France) and Cabos Series (N.W. Spain). The sediments displaying the mounds accumulated in partially protected tidal flat/ lagoonal environments immediately before and during major transgressions. The mounds are erosional features typically occurring on the tops of sheet sandstones (ca. 50–500 mm thick) some of which may have a storm washover origin. Mound genesis related to periodic emergence and late stage run-off is supported by their intimate association with mudcracks and other very shallow water features (e.g. bidirectional current-formed structures, wave ripples, ladder and interference patterns, mudflakes, etc.). Variation in mound morphology suggests that post-depositional dissection began as elongate ridge-gully couplets with secondary erosion of the ridge flanks leading to the development of more characteristic hemispherical geometries. Emergence may have been a function of tidal fluctuations and/or subsidence of storm surge events. Facies sequences point to the repeated filling of these inshore environments by storm washovers superimposed on ambient tidal conditions which possibly resulted from the progressive decay of beach barriers during transgression.  相似文献   

EXPANSION OF GOLF COURSES IN THE UNITED STATES*     

DARRELL E. NAPTON  CHRISTOPHER R. LAINGEN 《Geographical review》2008,98(1):24-41

ABSTRACT. Twenty‐five million Americans play golf on the nation's 16,000 courses each year. These golf courses constitute a significant national landscape feature. Since 1878, when the game arrived in the United States, golf has filtered down the urban, economic, and social hierarchies to become accepted by and accessible to most Americans. During the ensuing thirteen decades the number, location, and layout of the nation's golf courses have responded to many of the same driving forces that impacted the nation, including decentralization, growth of the middle class, war, economic depression, suburbanization, and the increasing role of the federal government. Four epochs of golf‐course growth and diffusion show the growing acceptance of the sport and depict where courses were most likely to be constructed as a result of the prevailing forces of each epoch.  相似文献   

The application of δ13C,TOC and C/N geochemistry to reconstruct Holocene relative sea levels and paleoenvironments in the Thames Estuary,UK          下载免费PDF全文

NICOLE S. KHAN  CHRISTOPHER H. VANE  BENJAMIN P. HORTON  CAROLINE HILLIER  JAMES B. RIDING  CHRISTOPHER P. KENDRICK 《第四纪科学杂志》2015,30(5):417-433

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Reconstructing Holocene sea level using salt‐marsh foraminifera and transfer functions: lessons from New Jersey,USA     

RICHARD J. TELFORD  BENJAMIN P. HORTON  SHIMON C. ANISFELD  CHRISTOPHER K. SOMMERFIELD 《第四纪科学杂志》2013,28(6):617-629

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Pollen stratigraphy of the Late Pleistocene sediments at Mommark, Als, South Denmark     

PHILIP GIBBARD  CHRISTOPHER GLAISTER 《Boreas: An International Journal of Quaternary Research》2006,35(2):332-348

Past environmental changes in the Baltic area are discussed on the basis of pollen and spores recovered from marine sediments in a series of cliff sections at Mommark, in southern Denmark. The sediment succession represents Jessen & Milthers' (1928) Eemian pollen zones c-h, or Andersen's (1961 1975) zones E1/2-E7, as well as the earliest Weichselian pollen zone i, or EW-1, the Herning Stadial. A correlation with annually laminated German sequences (e.g. Bispingen) indicates that the sequence spans approximately 11 000 years. Marine deposition began c. 300 years after the beginning of the Eemian Interglacial Stage and continued to shortly before the end of pollen zone E7, at c. 10 600 years after the beginning of the Eemian. Sedimentation rates varied through the time period represented by the sequence, with initial deposition relatively rapid at c. 0.35 cm yr^-1 for the first c. 300 years. Rates then decreased to 0.029 cm yr^-1 for the next 2700 years and remained low, though varying, throughout the rest of the sequence. Overall, the rates indicate that sediment supply was highly restricted throughout the interglacial, possibly reflecting the dense forest vegetation that colonized the hinterland.  相似文献   

Holocene tree‐limit and distribution of Abies alba in the inner French Alps: anthropogenic or climatic changes?     

CHRISTOPHER CARCAILLET  SERGE D. MULLER 《Boreas: An International Journal of Quaternary Research》2005,34(4):468-476

The expansion of silver fir (Abies alba) during the 20th century in the European inner Alps calls into question the causes of the observed dynamics. We investigate the past distribution of Abies alba via analysis of wood charcoal buried in natural soils (identification, weighing, dating) and of pollen and macro-remains from peat to help us understand its present-day expansion. Material was sampled in the driest areas of the inner French Alps - some samples from calcareous sites, and most from southern exposures that should exclude Abies alba, which is a drought and carbonate intolerant species. The regional tree limit of the silver fir has not changed significantly since the middle Holocene. Abies alba grew on southern exposures, even on calcareous soils, but its importance was higher on northern slopes. From 4000 to 2000 cal. yr BP, depending on sites, the species has experienced local extinction associated with fire history. Human impact, more than climate, appears to be the main factor for local extinction, indicating that the marked present-day expansion of silver fir may result from land-use abandonment.  相似文献   

Sedimentary facies of a glacially influenced continental succession in the Pennsylvanian Jericho Formation, Galilee Basin, Australia     

ANDREW T. JONES  CHRISTOPHER R. FIELDING 《Sedimentology》2008,55(3):531-556

Recent work on the Late Palaeozoic Ice Age in eastern Australia has shown the Joe Joe Group in the eastern Galilee Basin, Queensland, to be of critical importance as it is one of few records of Pennsylvanian glacial activity outside South America. This paper presents detailed sedimentological data, from which the Late Palaeozoic environment of the region is reconstructed and which, consequently, allows for robust comment on the broader Gondwanan glaciation. The Jericho Formation, in the lower Joe Joe Group, was deposited in an active extensional basin in lacustrine to fluvial environments, during the mid‐Namurian to early Stephanian. The region experienced a cool climate during this time, and polythermal mountain or valley‐type glaciers periodically advanced into the area from highlands to the north‐east. The Jericho Formation preserves a suite of proglacial to terminal glacial facies that is characterized by massive and stratified diamictites deposited from debris flows, massive and horizontally laminated conglomerates and sandstones deposited from hyperconcentrated density flows, laminated siltstones with outsized clasts and interlaminated siltstone/conglomerate deposited through ice‐rafting into lakes, and sedimentary dykes and breccias deposited through overpressurization of groundwater beneath permafrost. Non‐glacial facies are dominated by fluvial sandstones and lacustrine/overbank siltstones. The glacigenic rocks of the Jericho Formation are confined to discrete packages, recording three separate glacial advances during the latest Namurian to late Westphalian. This arrangement is consistent with the temporal distribution of glacigenic rocks from around the remainder of Australia and Gondwana, which supports the theory that glacial deposits occurred in discrete intervals. The Joe Joe Group is a key succession in the world in this context as, at this time, eastern Australia provides the only unequivocal evidence of a Namurian/Westphalian glaciation outside South America. The continuous record of sedimentation through the Pennsylvanian and Early Permian is indicative of significant warming between glacial intervals, which is difficult to reconcile with the development of long‐lived, cold‐based ice sheets across the supercontinent.  相似文献   

QUANTIFYING UNCERTAINTY IN USING MULTIPLE DATASETS TO DETERMINE SPATIOTEMPORAL ICE MASS LOSS OVER 101 YEARS AT KÅRSAGLACIÄREN,SUB‐ARCTIC SWEDEN          下载免费PDF全文

CHRISTOPHER N. WILLIAMS  JONATHAN L. CARRIVICK  ANDREW J. EVANS  DAVID M. RIPPIN 《Geografiska Annaler: Series A, Physical Geography》2016,98(1):61-79

Glacier mass balance and mass balance gradient are fundamentally affected by changes in glacier 3D geometry. Few studies have quantified changing mountain glacier 3D geometry, not least because of a dearth of suitable spatiotemporally distributed topographical information. Additionally, there can be significant uncertainty in georeferencing of historical data and subsequent calculations of the difference between successive surveys. This study presents multiple 3D glacier reconstructions and the associated mass balance response of Kårsaglaciären, which is a 0.89 ± 0.01 km² mountain glacier in sub‐arctic Sweden. Reconstructions spanning 101 years were enabled by historical map digitisation and contemporary elevation and thickness surveys. By considering displacements between digitised maps via the identification of common tie‐points, uncertainty in both vertical and horizontal planes were estimated. Results demonstrate a long‐term trend of negative mass balance with an increase in mean elevation, total glacier retreat (1909–2008) of 1311 ± 12 m, and for the period 1926–2010 a volume decrease of 1.0 ± 0.3 × 10^–3 km³ yr^–1. Synthesising measurements of the glaciers’ past 3D geometry and ice thickness with theoretically calculated basal stress profiles explains the present thermal regime. The glacier is identified as being disproportionately fast in its rate of mass loss and relative to area, is the fastest retreating glacier in Sweden. Our long‐term dataset of glacier 3D geometry changes will be useful for testing models of the evolution of glacier characteristics and behaviour, and ultimately for improving predictions of meltwater production with climate change.  相似文献   

Testing the sensitivity of the East Antarctic Ice Sheet to Southern Ocean dynamics: past changes and future implications          下载免费PDF全文

CHRISTOPHER J. FOGWILL  CHRISTIAN S. M. TURNEY  KATRIN J. MEISSNER  NICHOLAS R. GOLLEDGE  PAUL SPENCE  JASON L. ROBERTS  MATHEW H. ENGLAND  RICHARD T. JONES  LIONEL CARTER 《第四纪科学杂志》2014,29(1):91-98

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Evidence for carbonate platform failure during rapid sea‐level rise; ca 14 000 year old bioclastic flow deposits in the Lesser Antilles     

JESSICA TROFIMOVS  JODIE K. FISHER  HEATHER A. MACDONALD  PETER J. TALLING  R. STEPHEN J. SPARKS  MALCOLM B. HART  CHRISTOPHER W. SMART  GEORGES BOUDON  CHRISTINE DEPLUS  JEAN‐CHRISTOPHE KOMOROWSKI  ANNE LE FRIANT  STEVEN G. MORETON  MELANIE J. LENG 《Sedimentology》2010,57(3):735-759

Bioclastic flow deposits offshore from the Soufrière Hills volcano on Montserrat in the Lesser Antilles were deposited by the largest volume sediment flows near this active volcano in the last 26 kyr. The volume of these deposits exceeds that of the largest historic volcanic dome collapse in the world, which occurred on Montserrat in 2003. These flows were most probably generated by a large submarine slope failure of the carbonate shelf comprising the south‐west flank of Antigua or the east flank of Redonda; adjacent islands that are not volcanically active. The bioclastic flow deposits are relatively coarse‐grained and either ungraded or poorly graded, and were deposited by non‐cohesive debris flow and high density turbidity currents. The bioclastic deposit often comprises multiple sub‐units that cannot be correlated between core sites; some located just 2 km apart. Multiple sub‐units in the bioclastic deposit result from either flow reflection, stacking of multiple debris flow lobes, and/or multi‐stage collapse of the initial landslide. This study provides unusually precise constraints on the age of this mass flow event that occurred at ca 14 ka. Few large submarine landslides have been well dated, but the slope failures that have been dated are commonly associated with periods of rapid sea‐level change.  相似文献