摘要:

SUMMARYThe angle of climb of ripples in cross‐laminated deposits is governed by the simple relation:in which ζ is the angle of climb,Mis the rate of sediment deposition normal to the rippled bed,His the ripple height, andjbis the bedload sediment transport rate. After introducing sediment transport functions, this relation is developed using the assumptions of gradually varied flow to predict the spatial patterns of cross‐lamination types in deposits due to pure non‐uniform flow, pure unsteady flow, and simultaneous non‐uniform and unsteady flow. Most of the predicted patterns can be matched from the geological record, and the analysis affords a hitherto missing insight into the environmental significance of climbing‐ripple cross‐lamination. The analysis also results in a rigorous definition of the kinds of environmental interpretation that may legitimately be made from examples of th

ISSN:0037-0746    

DOI:10.1111/j.1365-3091.1970.tb00179.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

SUMMARYThe determination of the natural radioelements in suspended matter in rivers and estuaries, lead to a simple relation between gamma activity and turbidityT, such asNt=aTb(Ntcounting rate caused by turbidity,aandbexperimental coefficients). A new turbidimetry method is based on this relation and discussed here. In situ measurements have been conducted with field gamma scintillometers and compared with different turbidimetry methods, such as nephelometry, gravi‐metry and gamma ray absorptiometry. This method has been particularly convenient to continuous in situ measurements of turbidity from 0.5 g to several hundreds of g/1. This broad range is very well adapted to turbidity studies in estuaries.The new method has been applied to study suspended matter dynamics in the Gironde estuary (France) during November 1968, as a part of a more general study of natural radioactivity in terrigenous sediments brought into the ocea

ISSN:0037-0746    

DOI:10.1111/j.1365-3091.1970.tb00180.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

SUMMARYA new apparatus, the “buret cylinder”, was constructed in order to increase the efficiency of the size analysis of fine‐grained sediments. Its uncomplicated operation and automatic levelling enables working in series of ten samples or more at a time. This method, an improvement of the “pipet method”, works with an accuracy comparable to that of the “Atterberg method”.An ALGOL‐program was compiled to compute all data, obtained from the granulometric analysis of the entire sediment. In the output, the numerical parameters are printed out and a simple frequency and a cumulative diagram is plotted. The computer program works for grain sizes from −6 phi (64 mm φ) to +9 phi (2 u φ). Two procedures can be applied alternatively: (a) sieving—buret analysis; and(b)sieving—visual accumulat

ISSN:0037-0746    

DOI:10.1111/j.1365-3091.1970.tb00181.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

SUMMARYSphericity and roundness data of quartz grains (of varying size) of sieve fractions are empirically shown to be non‐normally distributed. It is also demonstrated that log10[ψ/(1−ψ)] and −log10(P) transformations, respectively, normalize the sphericity and roundness data, where ψ denotes the two‐dimensional sphericity andPthe roundness of the grains in a plane. Laboratory experiments on sampling quartz grains from a sieve fraction show that the cone‐and‐quartering method is preferable as it yields similar results to those of the more time‐consuming random sampling procedure. Results of laboratory measurement errors on two‐dimensional sphericity and roundness data are also presented. The frequency of sphericity and roundness data are noted on number basis.For all parametric statistical studies of sphericity and roundness the sample statistics should, therefore, be calculated according to the above normalizing log functions. Suitable grade scales of sphericity and roundness data are proposed here basing on these log functions and the total range and the minimum range of the variates (spheric

ISSN:0037-0746    

DOI:10.1111/j.1365-3091.1970.tb00182.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

SUMMARYThe combined use of size analysis and electron microscopy has indicated the presence of beach sands within the Lower Carboniferous Fell Sandstone of southeast Scotland and northern England.Environmental interpretations are based on a comparison of the statistical parameters summarizing the size distributions of the Fell Sandstone specimens with similar data from modern sediments. The spread of standard‐deviation values (sorting coefficients) indicates the presence of littoral, alluvial, and possibly offshore marine environments within the Fell Sandstone. These environments are further defined by plotting standard deviation against skewness on a scatter diagram.Electron micrographs (E.M.G.'s) of the quartz grain surface textures of selected Fell Sandstone specimens corroborate the interpretations based on the size analysis.E.M.G.'s of the Fell Sandstone beach specimens show all the diagnostic surface features developed on modern quartz beach sand grain

ISSN:0037-0746    

DOI:10.1111/j.1365-3091.1970.tb00183.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

SUMMARYPrimary sedimentary structures in modern point bar deposits of the Amite River in Louisiana and the Colorado River in Texas are analogous to features observed in Eocene Simsboro and Pleistocene Colorado River deposits of the Texas Gulf Coastal Plain.Short‐duration peak flow, channel pattern, average stream gradient of about 2–3 ft./mile, and bank stabilization by dense vegetation are major parameters controlling the depositional pattern of coarse sand and pebble gravel of the Amite and Colorado rivers. Stratification is directly related to specific depositional features and consists of: large‐scale trough‐fill cross‐stratification in the scour pool; trough‐fill cross‐stratification and foreset cross‐stratification in the lower point bar; parallel laminae, large foreset cross‐stratification, and trough‐fill cross‐stratification in the chute bar; parallel inclined laminae, climbing ripple laminae, and mud drapes in the chute fill; and parallel inclined laminae, mud drape, and foreset cross‐stratification in overbank, flood‐plain deposits.Fundamental differences between point bars of bed‐load streams (low suspended load/bed load ratio) and mixed‐load streams (high suspended load/bed load ratio) are that upper point bar sediments with small trough sets and parallel inclined laminae occur only in fine‐grained (mixed load) fluvial deposits, and large scale foresets of chute bars are common to coarse‐grained (bed load) fluvial deposits but are not found in fine‐grained fluvial deposits. Upward fining sequences, characteristic of fine‐grained fluvial deposits, are uncommon in sediments deposited by bed‐load streams such as the Amite and Colorado rivers.The Simsboro Sandstone consists mainly of scour pool, lower point bar, and chute bar sediments. Chute fill and flood‐plain deposits are preserved only in the highest stratigraphic sequence. Pleistocene Colorado River deposits display the same sequence of stratification types as the Sims

ISSN:0037-0746    

DOI:10.1111/j.1365-3091.1970.tb00184.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

SUMMARYInitial results of investigation of the diagenesis of calcareous algae by electron microprobe are:1A few conceptacles and other cavities in Recent algae specimens are partly to completely filled with younger carbonate. In contrast to the surrounding skeleton of about 10–20% mol MgCO3‐calcite, these deposits are either very low (0–2%) or very high (15–50%) in MgCO3content.2Highest magnesian values in Recent algae studied are thought to be in high‐Mg calcites rather than in any other phase, with very few possible exceptions.3Calcian dolomite replacing fossil algae in cores from Eniwetok Atoll commonly has Ca‐rich lenses resembling exsolut

ISSN:0037-0746    

DOI:10.1111/j.1365-3091.1970.tb00185.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

SUMMARYLate Quaternary clays in Haifa Bay and Ashdod Harbour are overconsolidated by desiccation. This conclusion was reached through analysis of the pre‐consolidation pressure as function of the actual overburden pressure, and by analogy with clays undergoing desiccation, and confirmed in laboratory experiments. It is in agreement with the known geology of the area.For pressures above 2.0 kg/cm2, a definite statistical relationship was established between the preconsolidation pressure and the in situ void ratio. For lower pressures, the in situ void ratio is mainly governed by environmental conditions during deposition and thought also to be governed by the clay mineralog

ISSN:0037-0746    

DOI:10.1111/j.1365-3091.1970.tb00186.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY

摘要:

Litho‐ and Bio‐Facies of Carbonate Sedimentary Rocks‐a Symposium.T. MATSUMOTO (Editor).Coasts and Beaches. J. A. STEERS.La Sédimentation des Evaporites. Comparaison des données sahariennes á quelques théories, hypothèses et observations classiques ou nouvelles.—Mém. Museum Hist. Nat. (Paris) Ser.C, XIX (

ISSN:0037-0746    

DOI:10.1111/j.1365-3091.1970.tb00187.x

出版商:Blackwell Publishing Ltd    

年代:1970

数据来源: WILEY