Basic Information in the Granitic Rocks of the Boulder Batholith

Dark fine grained basic masses of rock are found in nearly every part of the Boulder Batholith, these commonly being referred to as inclusions, segregations, autoliths, and various other names. The origin, distribution, and composition of the dark inclusions form the basis for this report.

An investigation of the mineralogy of uranium-bearing deposits in the Boulder Batholith, Montana : annual report, July 1, 1952 to March 31, 1953 /

"Contract No. AT(30-1)-1390."

Exploration diamond drilling in the Boulder batholith, Jefferson and Silver Bow Counties, Montana /

Radiometric logging of the drill holes was accomplished by means of a Geiger counter-type probe. Samples for chemical assay were selected after checking the core with a Geiger counter and correlation with the radiometric logging record. The exploration project did not disclose significant amounts of ore-grade material although encouraging indications were found at two different properties.

1954 exploration drilling in the Boulder batholith, Jefferson and Silver Bow Counties, Montana /

"DATE."

Age Relationships of Ore Deposits of Southwestern Montana (A Microscopic Study)

Although considerable work has been undertaken by some prominent geologists, the best known of which is that of Paul Billingsley and J. A. Grimes', in investigating the ore deposits of the Boulder Batholith and surrounding area, there has not been any complete microscopic investigation of these deposits, as a whole, published in the literature. With this in mind it was suggested to the writer by Professor Paul A. Schafer, of the Montana School of Mines, that a microscopic study of the ores of this region would be a worthwhile geologic problem. It was thought that the mineral association and the mode of mineral occurrence might afford methods of classify­ing these deposits so that they could be correlated with the age relationships worked out by Billingsley and Grimes.

A Microscopic Study of some Volcanic Rocks in the Vicinity of Butte

The rhyolite rocks in the vicinity of Big Butte present a very interesting, though complicated study. It seems that no extensive or conclusive work has ever been done upon these extrusives. I have found that the rhyolites present a very interesting problem, especially microscopically, and that no doubt an intensive study along these lines will solve the problems concerning age relations of different flows and origin of the magma that produced the material for emanations.

Attempted Proofs of the Differentiation of Magmas by Syntexis

This investigation was an effort to obtain proof of the much disputed principle that most of the observed mag­netic differentiations have been due to the assimilation, or syntexis, of the intruded country rocks.

Contact Metamorphism in the Highlands

On the southern margin of the Boulder Batholith, about twenty miles south of Butte in the Highland Mountains, there are many miles of contact between the igneous and sedi­mentary rocks. As two kinds of igneous rocks and many diff­erent kinds of sedimentary rock are present, it is an excell­ent place for the study of contact metamorphism.

The Acropolitan - v. 7, no. 2

In this issue...Dr. Coolbaugh, Montana Society of Engineers, Leonard Hoist House, Dancing Club, copper, Boulder Batholith, gold, Butte, Montana

Geology of the Tuxedo Mining District

The Tuxedo mining district lies fifteen miles west of Butte on the south east end of Deer Lodge valley. Prospecting and mining has been carried on in this district for about 20 years. As a result many pits have been dug, several adits have been driven, and two or three shallow shafts have been sunk.

Mineralization of the Bonanza Mine

The Bonanza mine of the Emery mining district in Powell County is on the largest veins in the area, and is developed to a depth of 680 feet by an incline shaft following the dip of the structure. Sulfide ores carrying gold and silver values are mined throughout the area which is easily accessible by road from Deerlodge, Montana, ten miles west of the district.

Geology of Smoke Hollow Area 8 Miles Southeast of Deerlodge, Powell County, Montana

This investigation was undertaken primarily as a problem in geologic mapping. The stratigraphy was studied as to the character, age, and sequence of the geologic formations that are exposed. The conclusions were based principally on the field relationships and lithology because no fossils were found.

Physiographic Surfaces and Weathering Near Butte

Three cycles of erosion have modified the Boulder batholith. The earliest cycle produced a peneplaination that has been largely obliterated by a partially completed intermediate cycle, and the recent cycle now in progress.

Boulder deposition during major tsunami events

A remarkable accumulation of marine boulders located above the present spring tide level has occurred in two coastal lowlands of the Algarve (Portugal). The size-interval of the particles studied here is seldom reported in the literature in association with extreme events of coastal inundation, thus making this study of relevance to many other coasts worldwide. The spreads of boulders extend several hundred meters inland and well beyond the present landward limit of storm activity. The marine origin of the boulders is demonstrated by well-developed macro-bioerosion sculpturing and in situ skeletal remains of endolithic shallow marine bivalves. The good state preservation of the fossils within the boulders indicates that abrasion duringtransport and redeposition was not significant. We envisage boulder deposition as having taken place during the Lisbon tsunami of ad 1755 through the simultaneous landward entrainment of coarse particles from nearshore followed by rapid shoreward suspended-dominated transport and non-graded redeposition that excluded significant sorting by weight or boulder dimensions. We use numerical hydrodynamic modeling of tsunami (and storm) waves to test the observational data on boulder dimensions (density, size, distribution) on the most likely processes of sediment deposition. This work demonstrates the effectiveness of the study of boulder deposits in tsunami reconstruction. Copyright (C) 2011 John Wiley & Sons, Ltd.