摘要:

AbstractAsymmetrical ripple marks formed by flowing water are described and classified on geometrical form, physical size, and hydrodynamic conditions of origin. By analysing models it is demonstrated that the character of cosets of cross‐strata resulting from the migration of asymmetrical ripple marks is dependent on ripple geometry and sediment supply. Predicted cross‐stratification patterns are shown to agree well with those described from water‐laid sediments. The use of cross‐strata in deducing sedimentation rates and depths of deposition is pointed out. Models are developed from natural situations for interpreting cross‐stratal dip direction patterns in shallow marine and deltaic

ISSN:0072-1050    

DOI:10.1002/gj.3350030201

出版商:John Wiley&Sons Ltd    

年代:1963

数据来源: WILEY

摘要:

AbstractA composite tectonic profile, from Clew Bay to central Murrisk is constructed and the sequence of structural events from the Upper Cambrian to post‐Wenlock—pre‐Viséan (C2S2) times is outlined. Four main structural episodes affected the Dalradian rocks in pre‐Arenig times. ‘Taconic’ thrusting and concentric folding were important, and finally a complex sequence of structures were variably imprinted on the Dalradian, Ordovician and Silurian rocks during post‐Wenlock, pre Visé

ISSN:0072-1050    

DOI:10.1002/gj.3350030202

出版商:John Wiley&Sons Ltd    

年代:1963

数据来源: WILEY

摘要:

AbstractIn his book “Structural Diagrams” (1958 Academy of Sciences of the U.S.S.R.) Vistelius proposes a scheme for the statistical analysis of fabric diagrams. The scheme is critically examined in this paper and found to be statistically invalid, largely due to a misunderstanding of the nature of the pole distribution in random diagr

ISSN:0072-1050    

DOI:10.1002/gj.3350030203

出版商:John Wiley&Sons Ltd    

年代:1963

数据来源: WILEY

摘要:

AbstractDoubt is cast on the general assumption that individual plutonic units were each emplaced in one intrusive act. Lack of internal contacts does not prove this assumption. It is suggested that all plutonic units may well have been intruded as a series of magmatic pulses, a number of temporally distinct injections that succeeded each other in such a way that none could develop clearly intrusive contacts against its immediate predecessor. This mechanism would ease the difficulty of explaining how plutons made room for themselves.

ISSN:0072-1050    

DOI:10.1002/gj.3350030204

出版商:John Wiley&Sons Ltd    

年代:1963

数据来源: WILEY

摘要:

AbstractA series of facies distribution maps with accompanying discussion is given for nine divisions of the Ludlovian; significant information on faunas and sedimentary features is incorporated. Isopachyte maps are presented for the whole of the Ludlovian and for its four component stages. Two sections are drawn across the area of sedimentation from northwest to southeast and northeast to southwest respectively. From the evidence assembled in these maps and sections deductions are made as to the probable palaeogeography of the Welsh Borderland area in Ludlovian times.

ISSN:0072-1050    

DOI:10.1002/gj.3350030205

出版商:John Wiley&Sons Ltd    

年代:1963

数据来源: WILEY

摘要:

AbstractThe Borrowdale Volcanic Rocks of the Seathwaite Fells, northwest of Coniston, Lancashire, consist of up to 13550 ft of lavas and tuffs, mainly andesitic in composition, but including some rhyolitic rocks among which are welded tuffs. They occupy a position in the lower part of the Borrowdale Volcanic succession and dip steeply to the southeast with little folding. A number of northerly trending faults and others with a trend between east‐northeast and east‐southeast traverse the area. Volcanic vents filled with agglomerate have been found at two pla

ISSN:0072-1050    

DOI:10.1002/gj.3350030206

出版商:John Wiley&Sons Ltd    

年代:1963

数据来源: WILEY

摘要:

AbstractThree olivine dolentes D1, D2, and D3 form a multiple intrusion of Tertiary age. The earlier intrusions, D1 and D2, fill the conduit in the lower part of the hill. The final intrusion D3 broke through the solid plug of D1 and D2 along restricted channels to fill the conduit in the upper part of the hill. The intrusions are exposed at the present erosion level of the Upper Basalts and near the top of the original lava‐plateau. D1 contains layers full of cognate platy xenoliths; D3, at the south end of the hill, is crowded with cognate xenolithic sheets, and similar sheets settled on to the floor of the D3 intrusion elsewhere. The xenolithic sheets are considered to be surface crusts formed at the top of the magma column and carried to their present place by the circulatory system of a lava‐l

ISSN:0072-1050    

DOI:10.1002/gj.3350030207

出版商:John Wiley&Sons Ltd    

年代:1963

数据来源: WILEY

摘要:

AbstractThe specimens ofEuestheriaoriginally found at Alderley Edge were given inadequate descriptions and their horizon is confused by conflicting statements. A revised account is given, incorporating information from newly collected material.

ISSN:0072-1050    

DOI:10.1002/gj.3350030208

出版商:John Wiley&Sons Ltd    

年代:1963

数据来源: WILEY

ISSN:0072-1050    

DOI:10.1002/gj.3350030220

出版商:John Wiley&Sons Ltd    

年代:1963

数据来源: WILEY