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The ore bodies of the Highland-Surprise Mine are replacements along shear zones in quartzose slate, quartzite, and phyllite of the Prichard Formation of the Belt series (Precambrian). Pyrite, arsenopyrite, pyrrhotite, sphalerite, chalcopyrite, and galena are the chief metallic minerals and were probably deposited in that order. Temperatures of formation were...

Hornblendes in amphibolite interlayers in the paragneiss of the northwest Adirondack Mountains undergo systematic changes in color, composition, and density during progressive metamorphism from almandine-amphibolite to hornblende-granulite facies. In contrast, indices of refraction of the hornblendes remain about constant. In the almandine-amphibolite facies the amphibolite layers have the bulk composition of a saturated basalt and...

Wood cut by Castor canadensis(?) has been found at or near the base of five peat deposits studied in open exposure. Beavers apparently entered the region about 12,000 years ago and rapidly occupied most low-lying places. Many existing bogs may be the result of early dams. The disturbance of pond sediments...

Late Cretaceous Tuscaloosa Formation occurs as discontinuous remnants that cap many of the ridges in the Western Highland Rim. Typically the formation consists of well-rounded, poorly sorted chert gravel which is trimodal in size distribution. The gravel fraction (mode 15 to 40+ mm) consists of Devonian and Mississippian chert and a small percentage of...

During experiments on sediment transport and resistance to flow with a uniform 0.33-mm sand, data were recorded on the movement of individual rocks having intermediate diameters from about 0.1 to 0.5 foot. The experiments were conducted in a flume 2 feet wide by 60 feet long and for most runs, depth was held...

The design and operation of a microscope freezing stage developed for use at magnifications up to 500X are described. It makes possible studies of low-temperature phase changes such as the freezing of a saline water phase, and hence an estimate of the total salt concentration, in fluid inclusions as small as 10 microns (10-6 milligram in...

Massive and disseminated pyrrhotite-chalcopyrite-pyrite ore replaced a fault zone in Precambrian Carolina Gneiss of Keith (1). Closely following sulfide deposition, vein sulfides and silicates in the wall rock were recrystallized under a rising temperature gradient to coarse-grained unoriented aggregates that contain late pyrite porphyroblasts in pyrrhotite. Boudinage, dilation, and flow structures are common....

Gold, silver, copper, and lead-bearing veins, non-radially zoned, occur just beyond the southern and western margins of the Searchlight, Nevada, quartz monzonite stock. Seven samples of the quartz monzonite and purified individual constituent minerals of the rock, representing apophyses and marginal and interior parts of the intrusive mass, were analyzed petrographically...

A pollen diagram from Kirchner Marsh, southeastern Minnesota, records a continuous vegetation sequence from the time of Late Wisconsin ice retreat from the region. The late-glacial and early postglacial portions of the diagram are correlated with a radiocarbon-dated diagram from Madelia, Minnesota. Both diagrams show a series of maxima of...

No abstract available....

No abstract available. ...

In natural scapolites the cell dimension a shows a regular increase from marialite to meionite composition, while c remains constant. Both a and c of synthetic meionite are larger than the corresponding dimensions of synthetic marialite. The cell volume of both natural and synthetic scapolites is a nearly linear function of composition. Variations in cell...

Tetraethyl lead is a normal constituent of vegetation growing along our highways. Washed grass near Denver contained 3000 ppm (in ash) near major intersections and > 50 ppm for 500 feet downwind. Vegetables grown within 25 feet of a road in upstate New York and western Maryland averaged 80 to...

No abstract available....

During early Late Cretaceous the area of the northern Mississippi Embayment was occupied by a structural and topographic dome standing nearly 1000 feet above sea level. Rocks as old as Cambrian were exposed on its crest. Downwarping of the dome, which commenced in Late Cretaceous time, resulted in the development of the Mississippi Embayment syncline, now filled...

An investigation of some aeromagnetic anomalies in north-central Montana shows that remanent magnetization is the dominant factor in anomalies over some rocks and a contributing factor in anomalies over others. In volcanic rocks, remanence is commonly south-seeking down and has an intensity approximately ten times the induced intensity of magnetization. Remanence is shown to be...

A trend toward increasing use of test drilling and subsurface exploration is resulting in a decreasing reliance on human experience in coping with problems in hydrogeology. Application of "observation and inference" and discreet abstraction of readily available data will solve more problems than is now realized. ...

The name jasperoid has been applied to rocks that consist mainly of silica and that have formed by replacement. This paper considers only those jasperoids formed by replacement of limestone. Major problems involved in the origin of such jasperoid include: source of the silica; nature of solutions that dissolve, transport, and precipitate silica; and...

No abstract available....

This article discusses the results of a controlled field testing program, which indicated that definite hydraulic and other advantages may be gained from induced recharging as practiced at Kalamazoo, Michigan. Results include the following: water levels and artesian pressures can be maintained at high stages, the results are lower pumping...

In 1961 a 1000-foot drill hole near Harwich on Cape Cod, Massachusetts, penetrated 435 feet of Pleistocene deposits above 50 to 60 feet of crystalline limestone and phyllitic schist, and more than 500 feet of phyllitic schist with abundant quartz veins. Similar rock is known in the Pennsylvanian and Precambrian...

In the Balmat area in northern New York, tabular deposits of sulfide minerals parallel the layering in folded, siliceous magnesian marbles of a metamorphic complex commonly referred to as the Precambrian Granville Series. Sphalerite, pyrite, and, locally, pyrrhotite and galena have replaced the carbonate minerals in parts of the marble units. The contacts...

No abstract available....

No abstract available....