摘要:

SUMMARYThe type Lindsey Bridge Member of the Moorefield Formation of northeastern Oklahoma consists of 24 ft. of massively cross‐bedded limestone. Cross‐bed shape, lithologic variation, grain size and sorting, distribution of insolubles, and distribution of fossils and fossil burrows can be explained with reference to a hydrodynamic model developed in recent flume studies.Three facies can be distinguished in this unit: (1Thei) foresets, thick‐bedded, well‐sorted, fine to medium crinoidal grainstones, dipping at angles up to 1° (2) toesets, which are thin‐bedded, poorly sorted, skeletal packstones notably more fossiliferous than the foresets, with which they are laterally gradational; toesets dip at approximately 5°‐8° (3) bottomsets, composed of argillaceous, fine‐grained (mainly silt‐size), skeletal limestones. Foresets overlie previously deposited bottomsets; this geometry is typical of regressive sedimentation.The exposure is adjacent to a pre‐Moorefield topographic high. As currents crossing this high entered a basin on the downcurrent side, flow separation occurred. Bed material load was deposited mainly on the foreset slope, suspension material mainly in toeset and bottomset areas. The poor sorting of the toesets is in part due to reverse circulation, formed by the flow separation, which transported bottomset sediment back toward the foreset. Jopling(1965b) has shown that this depositional geometry produces tangential cross‐beds similar to those seen in this outcrop. Differential settling velocity, substrate stability, and abundance of organic detritus influenced other sedimentologic pro

ISSN:0037-0746    

DOI:10.1111/j.1365-3091.1967.tb01312.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

SUMMARYA joint survey by the Woods Hole Oceanographic Institution and the U. S. Geological Survey, begun in 1962, aims at the geologic exploration of the Atlantic continental margin. This report describes the distribution of carbonate in the surface sediments between Nova Scotia and Hudson Canyon. Samples of surface sediment on a 10‐mile grid reveal that over more than 90% of its area the shelf sediment contains less than 5% calcium carbonate. These low values are due to low production by aquatic organisms, a consequence of low average water temperatures. A few locales on the shelf have high carbonate concentration owing to a prolific sessile or nearly sessile fauna. Seaward of the shelf concentrations of calcium carbonate increase regularly with depth to about 30% on the upper continental rise; this increase reflects a greater relative abundance of planktonic Foraminifera due to a decrease in the rate of deposition of land derived detritus. Limestone outcrops are very rare in the are

ISSN:0037-0746    

DOI:10.1111/j.1365-3091.1967.tb01313.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

SUMMARYLand plant debris occurs in appreciable quantities in the shelf sediments off Ventura, southern California. Concentrations range from less than 2 g (wet weight)/1 (less than 250 g/m2) to 53 g/1 (10,662 g/m2). The highest values are found near the outer edge of the shelf.

ISSN:0037-0746    

DOI:10.1111/j.1365-3091.1967.tb01314.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

SUMMARYThe deviation indexHqais studied by use of the A.F.N.O.R. set of sieves (the geometrical progression of mesh‐size has a ratio 1010 # 1.259). The author shows the connection betweenHqaand the sorting index (So) of Trask, and the connection betweenHqaand theQdφindex of Krumbein (Hq= 3Qdφ, approximate

ISSN:0037-0746    

DOI:10.1111/j.1365-3091.1967.tb01315.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

SUMMARYComputers are being used increasingly for the analysis of quantitative geological data. An outline is given of the advantages of contemporaneously using both computer and a connected automatic plotter. It is suggested that the quality of the automatic plotter output is such as to preclude the services of a draftsman in the preparation of many graphics for publication.

ISSN:0037-0746    

DOI:10.1111/j.1365-3091.1967.tb01316.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

摘要:

SUMMARYSaxena's(1966a) paper on the “Evolution of zircons in sedimentary and metamorphic rocks” is discussed. The arguments for the stability of zircon during sedimentary and metamorphic processes are reviewed. Saxena's idea of an authigenic origin of the majority of zircons in some sediments seems to be the result of a misidentification of authigenic titaniferous minerals as zir

ISSN:0037-0746    

DOI:10.1111/j.1365-3091.1967.tb01317.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

ISSN:0037-0746    

DOI:10.1111/j.1365-3091.1967.tb01318.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

ISSN:0037-0746    

DOI:10.1111/j.1365-3091.1967.tb01319.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY

ISSN:0037-0746    

DOI:10.1111/j.1365-3091.1967.tb01320.x

出版商:Blackwell Publishing Ltd    

年代:1967

数据来源: WILEY