British Earthquakes, University of East Anglia, 18–19 April 1985     

PETER J. SMITH 《Geology Today》1985,1(5):134-135

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The Quaternary of Scotland: Reviews in honour of J. B. Sissons     

DAVID E. SMITH 《Boreas: An International Journal of Quaternary Research》1986,15(2):153-154

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Submerged forest off Nyuzen, Kurobegawa alluvial fan, Toyama Bay, Central Japan   总被引：1，自引：0，他引：1  

SHOJI FUJII  NORIYUKI NASU  ALEC J. SMITH  NORIO FUJI  YOSHIHIKO MIZUTANI  MISABURO SHIMAKURA  KENJI KONISHI  CHIAKI IGARASHI  JUNRYO MURAMOTO  TOSHIO TAKEMURA  TAKASHI SHIMODA  SAM BOGGS JR.  KANTARO FUJIOKA  HARUNA MAPPA  HOTAKA KAWAHATA  YONG SAE KONG  TAKEO TANAKA 《Boreas: An International Journal of Quaternary Research》1986,15(4):265-277

Remnants of a submerged ancient forest have been found on the continental shelf of NW Japan off the Kurobe alluvial fan in Toyama Bay. The remains, standing tree stumps and roots, are located at depths between 20 and 40 m and ages of 8,000 years B.P. to 10,000 years B.P. have been determined by the ¹⁴C method. Alnus and Salix are the most commonly preserved genera and the trees grew on the now sub-merged seaward margin of the alluvial fan. Pollen analysis permits an estimate of palaeo-temperatures 2°C to 4°C lower than at present. Diatoms give some indication of salinity variations at the time of forest development and suggest brackish water, possible lagoonal conditions. The distribution of the stumps and roots suggests that there were probably two separate forests which were overwhelmed by rising sea-level and flash flood deposits. The present day submarine exposures may be due to recent submarine erosion related to the seaward movement of flood waters which passed from the fan into the upper reaches of the Toyama submarine canyon system.  相似文献   

COMMENT ON “ACOUSTIC MODELING OF THE SEA FLOOR” BY A.M. BERGE,G. DRIVENES,R. KANESTRØM AND B. BESKOW*     

D. TAYLOR SMITH 《Geophysical Prospecting》1986,34(1):141-142

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Grain-size characteristics of fine-grained unflocculated sediments I:'one-round' distributions   总被引：1，自引：0，他引：1  

KATE KRANCK†  P. C. SMITH  T. G. MILLIGAN 《Sedimentology》1996,43(3):589-594

A simple physical model of gravitational settling from an unsorted, unflocculated source suspension is presented and an equation derived to describe the grain-size spectra of the resulting bottom sediment. Results of grain-size analyses of sediments from a variety of environments and geographical locations are shown to conform with the postulated model. The characteristic size spectrum, termed ‘one-round’ sediment, identifies a deposit which has settled from suspension with no subsequent reworking resulting in modification of the grain-size distribution. The distribution of settling rates of grains in the suspension may be inferred from an analytical form fit to the bottom sediment grain-size spectrum, along with knowledge of certain physical characteristics of the fluid (e.g. mean velocity profile).  相似文献   

Grain-size characteristics of fine-grained unflocculated sediments II:'multi-round' distributions   总被引：2，自引：0，他引：2  

KATE KRANCK†  P. C. SMITH  T. G. MILLIGAN 《Sedimentology》1996,43(3):597-606

The grain-size spectrum of sediment deposited by settling of a suspension with a ‘one-round’ grain size distribution is described by a power law in which the integer exponent characterizing the fine-grained limb is increased by one over that of the suspension. If this better-sorted sediment, in turn, is resuspended and settles, further sorting and steepening of the limb occurs. Each resuspension event or‘round’changes the distribution by a predictable amount. Equations describing this sorting process, based on the derivation of the one-round equation, are fitted to grain-size analyses of well-sorted sediment from a variety of locations to verify the model. A suite of sandy bottom sediment samples from the Bay of Fundy shows that the steepness of the fine-grained limbs of the sand fraction indeed increases in integral steps.  相似文献   

Dynamics of sediment-laden underflows passing over a subaqueous sill: glacier-fed Peyto Lake, Alberta, Canada   总被引：2，自引：0，他引：2  

KAZUHISA A. CHIKITA  NORMAN D. SMITH  NOBORU YONEMITSU  MARTA PEREZ-ARLUCEA 《Sedimentology》1996,43(5):865-875

The dynamic behaviour of sediment-laden underflows was examined in Peyto Lake, Alberta, Canada, which contains a midlake sill 7 m high. Sediment-laden underflows are driven by the downslope component of negative buoyant gravity multiplied by the current's thickness. Our measurements of wind, lake currents and water properties indicate that underflows pass over the sill due to the active storage of turbid suspension near the bottom in the deepest proximal region. Sill overflows occurred only when a hydrological threshold of the inflowing river was exceeded, causing quasicontinuous underflow and associated sedimentation in the distal region of the lake basin.  相似文献   

Petrology and Mineral Chemistry of Plutonic Igneous Xenoliths from the Carbonatite Volcano, Oldoinyo Lengai, Tanzania   总被引：4，自引：0，他引：4  

DAWSON  J. B.; SMITH  J. V.; STEELE  I. M. 《Journal of Petrology》1995,36(3):797-826

Magmatic plutonic rocks in the Oldoinyo Lengai pyroclasticsare jacupirangite, pyroxenite, ijolite, nepheline syenite andwollastonitite. Mainly cumulates, they are combinations of nepheline,clinopyroxene, Ti-andradite, spinel (sensu lato), apatite, perovskite,titanite, wollastonite, sulphides, mica, glass and K-rich feldspar,most of which are strongly zoned. Low analytical sums for glasses,vesiculation of intergranular glasses, and the generally explosivenature of the volcanicity point to significant concentrationof dissolved volatiles in the parent magma; the absence of hydrousphases suggests that the dominant volatile is CO₂. Cumulatetextures, widely variable modes, veining and variation in specimenconsolidation and metasomatism all indicate derivation froma structurally complicated and multiply injected sub-volcaniccomplex. Complex zoning of phases and mineral disequilibrium is attributedto convective percolation of fluids through permeable cumulates,possibly complicated by magma replenishment during crystallizationof individual magma batches. Olivine, mica and pyroxene megacrystsin some ijolites indicate polybaric crystallization; mixingof potassic and sodic magmas may be the cause of these megacryst-bearingijolites, but the main parent is highly evolved, of carbonatedijolitic (nephelinitic) composition and with Nd and Sr isotopecharacteristics slightly more depleted than Bulk Earth. KEY WORDS: xenoliths; ijolite; jacupirangite; nepheline syenite ^*Corresponding author. Telephone 031 650 4837. Fax: 031 668 3184. e-mail: jbdawson{at}glg.ed.ac.uk  相似文献   

Stagnation points and bifurcation in 3-D mountain airflow   总被引：1，自引：0，他引：1  

RONALD B. SMITH  SIGBJØRN GRØNÅS 《地球，A辑:动力气象学与海洋学》1993,45(1):28-43

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SOME THEOREMS CONCERNING LOCAL MAGNETIC ANOMALIES     

R. A. SMITH 《Geophysical Prospecting》1961,9(3):399-410

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