A manual about the principles of geophysical well log correlation, together with examples of lithologic interpretation and expressions of stratigraphic and structural features which can sometimes be recognized on well logs.

The purpose of this manual is to compile under one cover the principles of well log correlation, together with examples of lithologic interpretation and expressions of stratigraphic and structural features which can sometimes be recognized on well logs.

Vein arrays are often composed of pull-aparts which are linked by shear fractures, good examples of which occur in the Lower Jurassic limestones of Somerset, southwestern England. Such pull-apart arrays have displacement-distance characteristics which are similar to fault zones, with maximum displacement (indicated by the largest pull-apart widths) near the centre of the array, and with displacement decreasing towards the tips. Pull-apart arrays usually die out into en echelon or pinnate veins. Evidence for pressure solution along the shear fractures which connect pull-aparts include their dark and braided nature, their obliquity to the displacement direction, the high dihedral angles (often > 90°) between conjugate shear fractures, and the dissolution of earlier structures. A range of geometries occurs, with varying relative amounts of veins and pressure solution being related to varying amounts of transtension or transpression. There is a general trend for an increase in the angle between vein segments and the shear fractures as contraction increases. There is therefore a trend for increased pressure solution on the shear fractures in more contractional arrays. The concentration of insoluble material along shear fractures has important implications for the mechanics and sealing of faults.

The Kokchetav microcontinent or the Kokchetav terrain distinguished by E.D. Shlygin [1] is a Precam-brian subplatform structure within the completed and uncompleted Caledonides. The Precambrian Kokchetav microcontinent is well distinguished in the geophysical fields, where the thickness of the Earth’s crust within the Continent ranges from 42 to 45 km [2], and the bounds of the microcontinent are traced by deep tectonic structures. Metamorphic rocks, developed within the microcontinent are divided into two series. The thickest lower (Zerendinskaya) series [3] consists mainly of metamorphic rocks of amphib-olite facies metamorphism. The upper (Sharykskaya) series is composed of Late Precambrian rocks metamorphosed under the green schist metamorphism. Both these series are separated by metamorphic and stratigraphic unconformity [3]. Precambrian rocks of both series were intruded by anomalously large masses of the Caledonian granitoids [4, 8]. The age of the rocks of the Kokchetav microcontinent remains a debatable topic. The analysis of the model age of the metaterrigenous rocks of the Zerendinskaya series (2.1–2.5 Ba) [4] and diamond-bearing gneisses of Kumdy-Kul (2.2–2.3 billion years) [5] allows us to conclude that the sedimentation of terrigenous material occurred as a result of the erosion of the Earth’s crust mainly in the Paleoproterozoic.

Harris Creek is a Au-rich, cobble-gravel bed stream in southern British Columbia, Canada. A preliminary study, based on analysis of < 0.053 mm sediments and heavy mineral concentrates (SG > 3.2) from bulk sediment samples, identified accumulations of Au at breaks-in-slope of the stream gradient. This is consistent with theoretical models of heavy mineral transport by streams (Day and Fletcher, 1991). However, the breaks-in-slope also coincide with active landslides that might, because of the form of the Au anomalies, be interpreted as the source of the Au. To investigate this we have: (1) monitored erosion of the landslides and determined their Au content; and (2) used multi-element geochemistry (with Al, Mg, Na, Ba, Ti, P and Sr) to fingerprint the influence of one of the landslides on the composition of the < 0.053 mm fraction of the stream sediments.

We present a ring-shear apparatus designed to deform soft, ductile rock analogues to arbitrarily high shear strains in simple shear, in experiments attempting to model processes that occur in natural ductile shear zones. The sintered specimen is deformed between two unsupported cylinders by two rotating grips, under a normal and shear stress up to 5 MPa and at temperatures up to 600 K. First results of experiments with octachloropropane (OCP, C3C18) and camphor (C10Hl6O) are presented.

Map measurements of the world’s coastline length have yielded a figure of 500,000 km. However, when all of the very real and intricate coastal crenulations are considered, the actual length is probably closer to 1,000,000 km. Added to this is the fact that 40% of the 6,000,000,000 people presently inhabiting the earth live within 100 km of a coastline. From these observations, it can be seen that coasts are a very major geo-morphic and social feature on the face of the planet. And for this reason, scholars in a multitude of disciplines have long been studying the many facets of the zone where the land meets the sea.

A mineral may be defined as any naturally occurring chemical element or compound formed as a product of inorganic processes. This eliminates all artificial products of the laboratory as well as all natural products formed by organic agencies. The above definition is brief; and, though it embraces most of the substances considered as minerals in this book, it should be considerably expanded to be all-inclusive.

Minerals are the materials of which most of the rocks of the earth's crust consist and are, therefore, among the common objects of daily observation. The great majority of rocks are not made up of single minerals, but are more or less heterogeneous aggregates of several different species. A few rocks, like limestone and quartzite, consist of but one mineral in a more or less pure state. In addition to occurring as essential and integral parts of rocks, minerals are found distributed through them in a scattered way, or in veins and cavities. <...>

The Republic of Georgia encompasses pan of the Alpine Himalayan fold belt; it extends from the northern slope of the Greater Caucasus to the Lesser Caucasus in the south, a geologically complex zone sandwiched between two lithospheric plates, the Afro-Arabian (Gondwana) and the Eurasian plates. More specifically it consists of the Greater Caucasus Range

to the north and the Transcaucasus to the south (Fig.l). The sutured boundary (the Sevan-Акега zone) lying between the Transcaucasus and the Lesser Caucasus to the south is effectively the northern margin of Gondwana. The northern boundary, between the Caucasus Mountains (sensu stricto) and the Scythian Platform, the southerly projection of the Russian Platform, is less clearly defined due to the superposition or panial superposition... <...>

During the ten years since the publication of the second edition of these tables many new minerals have been described. About fifty of these are included in the third edition of Part II,  which was published in 1933, while nearly seventy are of more recent date. The author has attempted to include in supplementary tables in this printing all the new minerals which seem to be well established and adequately described as to their optical properties. Unfortunately it has not been feasible to incorporate them in the main tables, but this is probably not a very serious difficulty since the minerals in question are all very rare.

It is hoped that the use of colored paper for the table (III) classifying minerals on the basis of their color (and pleochroism) in thin section will make it easy to find the various tables quickly and conveniently

In the preparation of this printing the author has benefited by the assistance and encouragement of his wife, Florence S. Winchell.

Folds form by ductile deformation typically involving continuous flow. In the elastico-frictional regime, such deformation may be accomplished by cataclastic flow involving collective movement on a population of fractures and zones. The Canyon Range (CR) syncline, part of the CR thrust sheet in west-central Utah, developed in this regime. The CR syncline is composed of thick-bedded quartzite units with a small material contrast between layers, limiting limb rotation by flexural slip alone. Thus, fracture populations developed to accommodate fold tightening by limb rotation and thinning, and the formation of transverse zones across the fold. Several generations of fracture and deformation zone (DZ) networks are recognized from mesoscopic and microscopic evidence, and can be related to stages of folding. The net result of the large number of distributed fractures and deformation zones is a continuous deformation that is homogeneous at the scale of the outcrop. All these lines of evidence suggest that large-scale cataclastic flow accommodated folding by allowing rigid mesoscopic blocks to slide along bounding DZs.

Along its length, the CR syncline consists of several segments bounded by transverse zones with different mechanisms accommodating fold tightening in adjacent segments. In one segment, fold tightening progressed by limb rotation, and then out-of-the-core thrusting. In contrast, fold tightening in the adjoining segments occurred by rotation and thinning of one limb and possible hinge migration, with the steeply dipping to overturned limb showing progressive thinning of units on a megascopic scale and progressive increase in the thickness and density of deformation zones at all scales