摘要:

AbstractDifferentiation in tholeiite magma, particularly iron enrichment and silica variation, as traced in lava successions and dolerite‐granophyre suites, is discussed in the light of analytical data on phenocryst and groundmass pyroxenes and their fractionation. Broadly two trends may be distinguished: (1) an intratelluric equilibrium trend ending in a hedenbergitic pyroxene phase fayalite, such as is exhibited by the Tasmanian Red Hill dolerite‐granophyre suite, and (2) a quench trend characteristic of the subcalcic augite groundmass sequence of the volcanic suites as exemplified in the Hawaiian tholeiite series (e.g. Kilauea). This trend may in more siliceous differentiates be extended to close with assemblages carrying a ferropigeonite ph

ISSN:0072-1050    

DOI:10.1002/gj.3350040111

出版商:John Wiley&Sons Ltd    

年代:1964

数据来源: WILEY

摘要:

AbstractThe Pendleside Limestone is redefined as comprising the B1(S2) zone and the lower part of the B2(D1) zone. It is argued that the Bowland Shales, including the basal beds of upper B2age, transgress the Pendleside Limestone northwards from Clitheroe, following a shallow earth‐movement with axes crossing the Ashnott Anticline, the Slaidburn Anticline and the Sykes Anticline. The Slaidburn Breccia is shown to be of lower B2age. There is unconformable overlap locally of the Lower Bowland Shale

ISSN:0072-1050    

DOI:10.1002/gj.3350040112

出版商:John Wiley&Sons Ltd    

年代:1964

数据来源: WILEY

摘要:

AbstractThis investigation of previously undescribed country along the Staffordshire‐Derbyshire border indicated the need for re‐examination of adjoining areas described in 1950 and 1951. The main revisions concern the ages of certain beds and the nature of the unconformities. Evidence is adduced of vertical earth‐movements in pre‐S2and in middle

ISSN:0072-1050    

DOI:10.1002/gj.3350040113

出版商:John Wiley&Sons Ltd    

年代:1964

数据来源: WILEY

摘要:

AbstractModern work on the analysis of folds is reviewed and traced to the work of Van Hise, Clough and Becker. Suggestions are made for the classification of folds and certain modern trends are criticised.

ISSN:0072-1050    

DOI:10.1002/gj.3350040114

出版商:John Wiley&Sons Ltd    

年代:1964

数据来源: WILEY

摘要:

AbstractPrevious research by the present author has established the Caledonian polyphase tectonics (F1, F2, F3) of the Manx Slate Series. Emplaced along the bedding or the first axial‐plane cleavage (S1) in these strata, and confined to a relatively narrow belt following the middle of the island, is a swarm of acid sheets which dip steeply and strike to the northeastern quadrant. Associated with these minor intrusions in the northeast of the island is the small Dhoon granite. The latter appears to have the form of a thick, lenticular sheet emplaced along S1and inclined steeply southward.All these intrusions are post‐F1in age. The field and textural evidence demonstrates their syn‐tectonic emplacement close to the hinge of the large‐scale F2Manx synform near the beginning of the F2episode. The strong deformation which they display was largely acquired during the F2movement. This includes shearing parallel to the margins of the intrusions, penetration by the second axial‐plane cleavage (S2), flexuring by minor F2folding and injection by syn‐tectonic F2quartz‐veining. The F3phase has also left a mild imprint upon the deform

ISSN:0072-1050    

DOI:10.1002/gj.3350040115

出版商:John Wiley&Sons Ltd    

年代:1964

数据来源: WILEY

摘要:

AbstractThis area of Wales is a westerly continuation of the northern limb of the Snowdon syncline and stretches from the Pre‐Cambrian volcanic series in the north to just above the abbreviated Snowdon Volcanic Series in the south. Large parts of the intervening area consist of Caledonian intrusive rocks, but the middle part of the sedimentary succession has yielded scattered graptolites, most and probably all, of Llanvirn age. The exposed volcanic rocks are largely of ignimbrite character while the Caledonian intrusions are of four types (for which chemical analyses are given). The sequence of these four rock‐types and of the structural events of the district is conside

ISSN:0072-1050    

DOI:10.1002/gj.3350040116

出版商:John Wiley&Sons Ltd    

年代:1964

数据来源: WILEY

ISSN:0072-1050    

DOI:10.1002/gj.3350040117

出版商:John Wiley&Sons Ltd    

年代:1964

数据来源: WILEY