摘要:

AbstractA surface resistivity survey around and to the south of Garstang has indicated a predominance of boulder clay, with some sands and gravels, in an overburden of markedly variable thickness and lithology. The survey techniques, data processing and interpretation are discussed. The data suggest that the Lower Boulder Clay may be represented northeast of Garstang, with the Middle Sands present over a much wider area. The major subdivision, the Upper Boulder Clay, seems to be overlain by patches of presumed Upper Sands. Possible isopachytes of these four suggested subdivisions are presented, and certain hydrogeological implications briefly mentioned.

ISSN:0072-1050    

DOI:10.1002/gj.3350080101

出版商:John Wiley&Sons Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractA rich microflora from the Waterstones of St. James' Cemetery, Liverpool, is noted. The age of this assemblage and of others recorded from the Waterstones Formation and associated strata is discussed.

ISSN:0072-1050    

DOI:10.1002/gj.3350080102

出版商:John Wiley&Sons Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractSmall‐scale thrust faults are described from the North Crop of the South Wales Coalfield in strata of Avonian age. Two main sets occur which strike at east‐west and north‐south respectively, and show apparent stratigraphic zonation. It is suggested that the sets were initiated during the early stage of deformation of the area in response to primary and secondary resolved compressional f

ISSN:0072-1050    

DOI:10.1002/gj.3350080103

出版商:John Wiley&Sons Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractArenig sandstones, grits and conglomerates rest unconformably on pre‐Cambrian rocks (the Mona Complex) and are of variable thickness and facies. Higher Arenig and Llanvirn shales, grits, conglomerates, shaly breccias and ironstones are related to contemporaneous fault movements, with abundant slump structures and rare turbidites. A pre‐Caradoc break in sedimentation was followed by deposition of shales, cherty shales, sandstones, breccias and conglomerates on Llanvirn, Arenig and pre‐Cambrian rocks. The Carmel Head Thrust acted as a major line controlling sedimentation, with upthrow to the north. Lower Silurian graptolitic shales at Parys Mountain rest on an acid volcanic group of Caradoc (?

ISSN:0072-1050    

DOI:10.1002/gj.3350080104

出版商:John Wiley&Sons Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractThe melting relations of a group of oceanic basalts—olivine basalts, tholeiitic to midly alkaline, and high‐alumina tholeiites are determined. The liquidi of these rocks follow closely the course of the temperature—iron enrichment relationship of Kilauean thoeliitic basalts, ranging from 1430°C for an olivine enriched tholeiite, to a tholeiite of liquidus temperature of 1190°C, the liquidus phase of the assemblages being either olivine or plag

ISSN:0072-1050    

DOI:10.1002/gj.3350080105

出版商:John Wiley&Sons Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractThe melting relations of a group of ultra alkali lavas are determined. They include a range of types rich in melilite and nepheline (melilite nephelinites) from the Nyiragongo volcano of the Congo and a group rich in olivine (olivine nephelinites).The liquidi of these assemblages range from 1100°C (the melilite nephelinite of the lava lake of Nyiragongo) through the Cameroons etindite (clinopyroxene nephelinite, 1118°C to 1300°C for the olivine nephelinites.For the most part the liquidi follow a course dependent on iron‐enrichmcnt. Notable departures are examples rich in leu

ISSN:0072-1050    

DOI:10.1002/gj.3350080106

出版商:John Wiley&Sons Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractThe normative mineralogy of the Loch Borralan, Loch Ailsh and Loch Loyal leucosyenites is compared to the System Ab – Or – An ‐ Qz. At Borralan, the upper quartz‐syenites of Cnoc‐na‐Sroine plot within the plagioclase volume, the lower perthosites within the alkali feldspar volume. This mineralogy cannot have been attained byin situcrystal fractionation. The Ailsh rocks plot within the plagioclase volume, the Loyal syenites within the alkali feldspar volume. The three complexes cannot have been derived from a single magma body at depth, and are not preci

ISSN:0072-1050    

DOI:10.1002/gj.3350080107

出版商:John Wiley&Sons Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractVitrinite from the Devonian Gramscatho Beds at Pendower in southwestern Cornwall displays optical properties which indicate an extremely high rank (meta‐anthracite). Despite this high rank, wood structures are clearly evident in polished sections between crossed polars. Some coke is present and this feature, together with the optical properties of the main vitrinite mass, suggests that relatively high temperatures (probably in excess of 350°C), were associated with the metamorphism of the host rocks. Reflectivity measurements on oriented blocks show that the vitrinite is optically biaxial, which conflicts with the widely accepted view that vitrinites are negative uniaxial materia

ISSN:0072-1050    

DOI:10.1002/gj.3350080108

出版商:John Wiley&Sons Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractMultiple siltstone dykes intruded parallel to cleavage in the Ludlovian argillites and graywackes of the Lake District throw new light on the origin of slaty cleavage. Pore pressures equalling lithostatic pressure developed during the Caledonian orogeny and caused tectonic dewatering of the partially lithified sediments. Slaty cleavage was initiated as an essentially planar structure by the intrusion of thin pelitic folia during the escape of the pore water. Cleavage folia and fold axial planes may have a common geometric relationship to the deforming stresses, but are independent of each other in origin. Continued deformation after tectonic dewatering refracted the cleavage by rotation of competent layers. Critical examination of evidence supporting traditional theories of slaty‐cleavage formation shows that all observed relationships are compatible with the tectonic‐dewatering the

ISSN:0072-1050    

DOI:10.1002/gj.3350080109

出版商:John Wiley&Sons Ltd    

年代:1972

数据来源: WILEY

摘要:

AbstractAn old land surface carved out of basement gneisses is extensively preserved beneath Torridon Group sandstones (depositedca.750 m.y. B.P.). Contoured reconstructions show that relief declines westward from 2000 ft (600 m) to almost nothing over a distance of 25 km. North‐northeast trending zones of similar dissection can be traced for 160 km. Weathering up to 2 m deep is locally present in the flat zone. The essentially unweathered land surface forming the mountains probably originated by dissection of a palaeoplain. The flat zone is probably, but not certainly, a relatively young pediplain. All land forms are thought to have developed before, not during, deposition of the overlying sediment

ISSN:0072-1050    

DOI:10.1002/gj.3350080110

出版商:John Wiley&Sons Ltd    

年代:1972

数据来源: WILEY