摘要:

SUMMARYA technique for mounting sand grains in transparent plastic rods is outlined. Four simple devices to facilitate the preparation and handling of the rods are described. These comprise a demountable mould, a grain lifter, a polishing jig and a microscope stage jig.

ISSN:0037-0746    

DOI:10.1111/j.1365-3091.1966.tb01893.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

SUMMARYGlauconite pellets exhibit considerable variety in morphology and internal structure. Recognized morphological types are: (1) ovoidal or spheroidal; (2) tabular or discoidal; (3) mammillated; (4) ellipsoidal; (5) vermicular; (6) composite; and (7) fossil casts, internal molds, or replacements. Types of internal structures include: (1) random microcrystalline, (2) oriented microcrystalline, (3) micaceous, (4) organic (?) replacements, (5) coatings on detrital grains, and (6) fibroradiated rims.These characteristics can be used to interpret the origin and/or subsequent history of pellet types. Suggested origins include: (1) chemical precipitation, (2) expansion and alteration of detrital mica, (3) alteration of fecal pellets, (4) alteration of clay fillings of fossil tests, (5) mechanical aggregation, and (6) chemical replacement.Not all glauconite pellets exhibit diagnostic characteristics with regard to their genesis. Original morphologies may be obscured by abrasion (reworking) prior to final burial. Internal structures may be changed by recrystallization or other diagenetic processes.It is concluded that glauconite pellets have multiple origins. They can form from several different parent materials and by several different processes. Frequently, however, characteristics which might reveal the original nature of the pellets have been lost during reworking and diagenesis.Inasmuch as glauconite occurrences differ in kind and variety of pellets, recognition of pellet types and their distribution is potentially useful for stratigraphic correlation or environmental determinations.

ISSN:0037-0746    

DOI:10.1111/j.1365-3091.1966.tb01894.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

SUMMARYExperiments on the uptake of boron by some clays from artificial sea‐water solutions at room temperatures show that the uptake is proportional to the concentration in solution, and takes place in relatively short time. The uptake process can be described by the Freundlich adsorption equation, with the constants in the equation, k and b, varying from one clay to another. Additional factor which apparently promotes the boron adsorption by clays is the occurrence of a sodium‐borate complex in saline waters. The boron concentrations in a sequence of marine Cretaceous sediments derived from a fairly localized source area show variation much greater than can be accounted for by a model which assumes (1) nearly constant boron concentration in illitic‐montmorillonitic clays prior to their deposition in the sea, and (2) changes in the boron concentration in solution as may be expected under slight variations in sea water of near “normal” salinity. Differences in the properties of clay‐mineral polymorphs, in predepositional histories of the clays, and possible adsorption from interstitial waters, render inconsequential the estimates of the boron concentrations in the waters at the time of

ISSN:0037-0746    

DOI:10.1111/j.1365-3091.1966.tb01895.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

SUMMARYCommercially available, daylight and near‐ultraviolet fluorescent, colored dyes can be used in long‐ or short‐lived surface coatings on coarse sediments. Such tracer coatings make possible day‐ or nighttime visual and quantitative determination of river or beach sediment transport. Testing of five commercial coatings led to formulation of two additional coatings. A wide selection of dye colors is available for use in four coating mixtures. All coatings are insoluble in fresh or saline water. Single‐application coating thicknesses range between 0.0003 and 0.0024 inches. Still air drying time at room temperature for separated particles varies from 40 seconds to 14 minutes depending on coating mixture used. Volume production of marked particles in the field is possible.Extensive sediment sampling in particle transport studies possibly may be eliminated by measuring visible light emission from coated particles under nearultraviolet excitation. A battery operated, portable photometer was assembled from a light cell, linear amplifier, and metering circuit. Laboratory calibration indicates that 5% differences in areal concentration of marked particles at given sampling locations can be determined.Color coded sizes of fluorescent sand and gravel were used in a test of foreshore sediment transport pattern over a single tidal cycle. Initial trajectory (minimum transport angle) of particles moved by beach drifting is approximately equal to deep water angle of wave approach relative to the shoreline. Angular magnitude of the dispersion zone for each group of particles seems to be a function of particle size and point of introduction on the foreshore. Minimum average transport velocity of particles was 0.42 ft./min under test c

ISSN:0037-0746    

DOI:10.1111/j.1365-3091.1966.tb01896.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

SUMMARYThe angle of repose under water is experimentally determined for a single particle on a fixed rough bed.The effect of grain shape, size and sorting of the bed and ratio of particle diameter to average bed grain diameter are taken into account. An empirical equation is given for predicting angle of repose as a function of the above factors. The accuracy of fit of this equation is quite good. Several other conclusions drawn for the case of a single grain on a fixed rough bed are:1Angle of repose increases with decrease in size, departure from sphericity and increased angularity.2Angle of repose increase with decrease in sorting.3A single angle of repose for sand size grains is not valid. Variation ranges from nearly 90° to less than 20°, depending on the values of the factors given abov

ISSN:0037-0746    

DOI:10.1111/j.1365-3091.1966.tb01897.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

SUMMARYSedimentary and meteorological characteristics of easterly dust storms causing severe damage in the Negev in November 1958 are analysed. Though the heavy storm originated in weather conditions outside of the affected area, the intense dustiness was of a more local nature. The sedimentological character of the dust indicates that the largest portion was of local origin, picked up by the turbulent current in the loess area of the northern Negev on its passage westward. Total quantity of sediment transported in the Beersheba Basin is estimated to be 10–20 million tons.The analysis of climatic data and of sedimentary characteristics of several other dust samples indicates that though severe dust storms can produce dramatic effects in transporting and deposition of aeolian dust, the rare occurrence of easterly dust storms does not make it likely that they were responsible for the import of aeolian sediments found in the northern Nege

ISSN:0037-0746    

DOI:10.1111/j.1365-3091.1966.tb01898.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

SUMMARYPetrographic examination of some Werfenian limestones of the Dolomite region in northeastern Italy has revealed these iimestones to show an unusual granular texture. This texture seems to have originated during an early resedimentation attempt when the sediments in which they occur were still water impregnated. Because these “pseudo‐grains” never existed as free clastic entities but yet recall intraclastic grains they are defined as protointruclusts and the rock asprotointruclastic mi

ISSN:0037-0746    

DOI:10.1111/j.1365-3091.1966.tb01899.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

SUMMARYThin‐sections of clays can be produced very rapidly and without impregnating by smoothing a face on dry glass plates, mounting the chip on “Araldite” adhesive and finally washing off the clay. A thin film of clay is preserved with larger mineral grains held firmly in place. This is suitable for wet staining techniques or for covering with Canada b

ISSN:0037-0746    

DOI:10.1111/j.1365-3091.1966.tb01900.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

SUMMARYThe present paper describes the use of cellulose acetate replicas in the study of silicate rocks, particularly indurated sandstones. The procedure of Boardmanand Utgaard(1964) for the reproduction of surface structures of polished limestone slabs for the study of Paleozoic Bryozoa, was modified and applied on silicate rocks using HF instead of formic acid as the etching agent.The polished slabs are etched with 40 % HF for 5–10 seconds and then washed, dried, wetted with acetone and gently pressed towards a mount of cellulose acetate. After drying, the specimen is quickly removed and an imprint is left on the acetate peel. By using thick (1.6 mm) cellulose acetate sheets no mounting on glass slides is needed, and the replica can be studied directly under the microscope or be used as a photographic negativ

ISSN:0037-0746    

DOI:10.1111/j.1365-3091.1966.tb01901.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY

摘要:

Book reviewed in this article:The Techniques of Sedimentary Mineralogy‐Developments in Sedimentology. 4. F. G. TickellSedimentary Features of Flysch and Greywackes‐Developments in Sedimentology. 7. S. Dzulynskiand E. K. Walton.Handbuch der Stratigraphischen Geologie. IV. Jura. H. Hö

ISSN:0037-0746    

DOI:10.1111/j.1365-3091.1966.tb01902.x

出版商:Blackwell Publishing Ltd    

年代:1966

数据来源: WILEY