Hydrogeology, waste disposal, science and politics. Proceedings of the 30th symposium on engineering geology and geotechnical engineering, Idaho, March, 1994

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GENERAL 945001 Hydrogeology, waste disposal, science and politics. Proceedings of the 30th symposium on engineering geology and geotechnical engineering, Idaho, March, 1994 ed P. K. Link, (Idaho State University), ISBN (paperback), 1994, 652 pp. These proceedings contain 49 papers presented at the symposium. Papers have been sorted into the following 8 sections: site characterisation - Pocatello area; site characterisation - Boise area; site assessment; Idaho national engineering laboratory; geophysical methods; remediation; geoteehnical engineering; and hydrogeology, northern and western Idaho. The papers vary from theoretical modelling through to actual case studies. Many are abstracted separately. -R.Gower 945002

Volume 2

Geot~chnics in the African

environment.

ed G. E. Blight, A. B. Fourie, I. Luker, D. J. Mouton & R . J . Scheurenberg, (A.A. Balkema), ISBN (hardback) 90 5410 009 5 (vol. 2) 90 5410 007 9 (set of 2 vols), price D r 295.00 (£92.00), 1994, 152 pp, index. This volume comprises the continued proceedings of the tenth regional conference for Africa on soil mechanics and foundation engineering, and the third international conference on tropical and residual soils, Masem, September 1991. This second volume present 11 papers, (abstracted separately), from the conference, including special lectures, general reports and late papers, and the presidential address. Topics covered in thts volume include: genesis and classification of tropical residual soils for engineers; general report on tropicaland residual soils; the geology of southern Africa; the Lesotho Highlands Water Project; geotechnical aspects of an access road construction; geotextile use; cyclic triaxial testing of road pavements; dam design; and geotechnical education. -R.Gower 945003 The Netherlands without engineering geology: no lands E. F . J . De Mulder, Engineering Geology, 37(I), 1994, pp 5-14. Through the ages, The Netherlands have been struggling with encroaching water, both from the sea, from rivers and from the ground. The western part of the country, where the majority of the population is living, is situated almost entirely below sea l e v e l Because large parts of the country are composed of a thick succession of unconsolidated younger Quaternary (Holocene) deposits, almost all constmctions have to be built on a foundation of piles driven down to firm Pleistocene sands to support them. These exceptional geographical, hydrological and geological conditions have prompted extensive studies in soil-mechanical engineering, and have generated special surveyin.g techtuques and special geological mapping techniques m areas where natural outcrops do not occur. Some projects intended to focus attention on and to promote engineering geology in The Netherlands are described. -from Author

GEOLOGY Tectonic processes and structural geology 945004 Rotational quantities in homogeneous flow and the development of small-scale structure W . D . Means, Journal of Structural Geology, 16(4), 1994, pp 437-445. A summary discussion is given of attempts to quantify the degree of non-coaxiality of rock flow from observations of rock structure, and of some principles governing the semitivity of structure to non-coaxialtty. The kinematic vorticity number has been estimated for naturally deformed rocks from three localities. These yield vorticlty numbers ranging from 0.35 to 0.9, corresponding to flows intermediate in character between pure and simple shearing. -Author

945005 The role of a s y m m e t r y in the formation of structures D. G. De Paor, Journal of Structural Geology, 16(4), 1994, pp 467-475. Asymmetric fabrics elements abound in deformed rocks. They are best understood by revising assumptions regarding the asymmetry, homogeneity and steadiness o f the stress, strain and kinematic regimes operative during tectonism. With the aid of new off-axis Mohr circle constructions, the ramifications of asymmetric tensor phenomena may be evaluated and the link between theory and observation may be strengthened. Stress in rocks is always a symmetric tensor phenomenon under conditions of equilibrium and homogeneity but it may be asymmetric in certain circulstances, resulting in the development of only one of a possible pair of symmetric conjugate structures. -from Author 945006 Determining the slip vector by graphical construction: use of a simplified representation of the stress tensor J.-F. Ritz, Journal of Structural Geology, 16(5), 1994, pp 737-741. A classification of tectonic stress regimes and a simple graphical construction of the slip vector applied on a fault plane are proposed, from a simplified expression of the stress tensor such that its components depend only on the stress ellipsoid shape ratio. -Author 945007 Seismically inferred dilatancy distribution, n o r t h e r n B a r b a d o s Ridge decollement: implications for fluid migration and fault strength T . H . Shipley, G. F. Moore, N. L. Bangs, J. C. Moore & P.L. Stoffa, Geology, 22(5), 1994, pp 411-414. A 5 x 25 km, three-dimensional seismic survey of the lower part of the northern Barbados Ridge accretionary prism creates a three-dimensional image of a major active decollement fault. The fault is usually a compound negative-polarity reflection modeled as a low-velocity, highporosity zone less than - 1 4 m thick. This thickness is significantly less than that defined by drilling of a >40 m zone of deformation at Ocean Drilling Program (ODP) Site 671B, located within the surveyed area. It is inferred that the seismically defined fault is a thin, high-porosity zone and is thus an undercompacted, high-fluid-pressure dilatant section. If these inferences are correct, then map-view variations in seismic-reflection waveform and amplitude illustrate complex patterns of fault-zone fluid content and fluid migration paths. The amplitude map suggests kilometrewide channels of locally high porosity and thus focused fluid flow. These paths are only subparallel to the expected minimum head, as inferred from the shape of the overlying sediment wedge; other factors must modify fluid concentrations and ultimately migration. -from Authors 945008 Characteristics of inland Q u a t e r n a r y basins in northwest China with reference to their hydrological significance Chen Mengxiong, Engineering Geology, 37(1), 1994, pp 61-65. Quaternary island basins are well-developed in northwest China, better known as the typical Gobi Desert area. Most of these Quaternary basins are features inherited from Meso-Cenozoic basins. They are characterized by long sequences of gravel formations and strong neoteetonics. Several patterns of basin structures have been classified on the basis of different intensities of neotectonic movements. This paper gives a detailed analysis of the sedimentary and structural features of these different basin types paying special attention to their hydrological significance. -Author 945009 Strain analysis using deformed vesicles from Mesozoic Pir Panjal volcanics, Kashmir Himalaya, India P . K . Gangopadhyay, S. S. Sarkar & G. K. Basu, Journal of Himalayan Geology, 3(I), 1992, pp 13-19. Present work, based on a sequence of deformed rectabasics, belonging to the Pit Panjal traps at and around Banihal Kashmir Himalaya indicates the presence of a conspicuous stretching lineation defined by the longest axes of