Cavities, surface topography, and inhomogeneities in elastic constants all distort the strains and tilts produced by stresses in the earth. Hence locally observed strains and tilts deviate from those calculated on the basis of simple earth models. We investigate these deviations on the assumption that the scale of these inhomogeneities is small in comparison with that of the stress fields. The results are applicable to observations of free modes, earth tides, and regional tectonic stresses. Analytical results are given for the deformation of an ellipsoidal cavity in a homogeneous medium in which the strain is uniform at large distances from the cavity. One important result is that greatly magnified strains are expected across narrow cavities. Finite element techniques are employed to study two features of importance in actual cavities, the influence of the corner in a tunnel of square cross section and the influence of the end face in a cylindrical tunnel with plane ends. The floor of the perfectly regular square tunnel remains flat, but irregularities produce large local tilts. Longitudinal strain in the cylindrical cavity is magnified near its ends, and most of the anomalous strain is concentrated within one tunnel diameter of the end. Topographic effects are also studied by finite element techniques. These are found to be very large and to result in strain magnifications in valleys, strain diminutions in hills, and strain‐induced tilts which are different for vertical and horizontal surfaces. In one case, regional compression actually results in local tension, and even a 1 in 10 (5.7°) slope produces a 36% perturbation in strain. Geological effects are investigated for a profile near Boulder, Colorado, where there is a very abrupt transition between the sedimentary rocks of the plains and the basement rocks of the Front Range of the Rocky Mountains. The surface strains perpendicular to the boundary fall from 177% to 37% of their regional values on crossing this boundary, and strain‐induced tilts attain values of about 0.5 times the regional strain in its vicinity. Long‐base strain meters and tiltmeters can give good results in underground sites, but short‐base instruments are very susceptible to local effects arising from geometric irregularities or rock inhomogeneities. Corrections for local topography are required for most installations. This topographic effect can be exploited to measure regional strains with tiltmeters, while the geological effects provide the basis of a technique for using earth tide observations to explore geological structure.

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Melville Island extends across the Cambrian through Devonian Arctic Platform and Franklinian Mobile Belt, and unconformable post-Devonian cover of the Sverdrup Basin. A revised geological map and seismic profiles provide insight into bedrock geology to depths exceeding 20 km. Possible Precambrian basement is identified at the deepest levels, as are three Proterozoic(?) seismic successions deformed and eroded prior to the Early(?) Cambrian. Cover includes a Cambrian(?) through Devonian shelf-margin wedge that increases in thickness northward to a maximum exceeding 10 000 m. The overlying Devonian clastic wedge (3000þ4600 m) represents the depositional record of the ancestral Ellesmerian Orogeny, southerly directed deformation that eventually produced the exposed salt-based fold belt and terminated lower Paleozoic sedimentation. The fold belt is continuous downward with a bivergent, thrust-faulted interval with up to 15 per cent shortening, and a basal detachment at 5 km. Long-lived deep-seated thrusts and other faults terminate below the sub-salt décollement and lie within large anticlinoria near the present margin of the Sverdrup Basin. Ellesmerian deformation continues to the west where style is apparently related to slip on a mid(?)-Cambrian detachment. Six additional Devonian and younger phases of deformation are recognized. Commodities of economic interest on Melville Island include natural gas, oil sand deposits, coal, showings of copper, lead and zinc sulphides, native sulphur, phosphorite and extensive subsurface rock salt.

In 1984, Canada and the USSR entered into an Arctic Science Exchange agreement, an important theme of which is the comparison of the geological evolution of the Arctic regions of both countries. Before 1984, progress in understanding the geology of the Arctic was hindered by political and cultural barriers. Soviet and western scientists had not enjoyed easy access to each others' field areas, and this inhibited understanding and exchange of data. The 1984 agreement between Canada and the USSR 1 for scientific and technological exchange in the Arctic represents a major step forward in the pursuit of understanding the geology of the Arctic region. This report, on the geology of a remote and important Russian island, is a direct result of this exchange, and this cooperative effort will be a landmark in providing new constraints to regional plate tectonic models and in providing basic information to aid in exploration and evaluation of the resource potential of the Canada Basin region.

SynopsisThermodynamic studies of the binding of adamantanecarboxylate to cyclodextrins have been made as a function of temperature and added organic cosolvent (methanol) using flow microcalorimetry. The negative heat capacity change associated with the adamantanecarboxylatelp-cyclodextrin interaction and the fact that the interaction is weakened by the addition of methanol implicate the binding process as being a hydrophobically driven one. The negative enthalpy change (AHo = -5.5 kcal/mol) and near-zero entropy change (ASo = 1.5 cal/mol deg) are quite different from the values normally expected for a hydrophobic bond, indicating that other bonding forces are important in addition to the hydrophobic effect. The relative contribution of the hydrophobic effect and other bonding forces (most likely van der Waals forces) to the overall binding was judged from an analysis of the dependence of the thermodynamics of the association process on the surface tension of the water-methanol mixtures following a model for "solvophobic" bonding described by Sinanoglu [Molecular Associations i n Biology (1968) Academic Press, New York, pp. 427-4451. From this analysis, adamantane-carboxylate/cyclodextrin complex formation is found to be driven to the extent of -1.9 kcal/mol by the hydrophobic effect. Furthermore, the hydrophobic driving force is found to be characterized by a positive ASo of 10 cal/mol deg. The remaining free energy of binding (and the AHo of binding of --6 kcal/mol) is then due to the intrinsic (surfacetension-independent) van der Waals interaction between the ligand and cyclodextrin cavity.