Contrasting origins of Cenozoic silicic volcanic rocks from the western Cordillera of the United States

2007 ◽  
Vol 70 (3) ◽  
pp. 251-267 ◽  
Author(s):  
Eric H. Christiansen ◽  
Michael McCurry
Keyword(s):  
United States ◽  
Volcanic Rocks ◽  
The United States ◽  
Western Cordillera ◽  
Silicic Volcanic

The Beginnings of Microscopic Petrography in the United States, 1870-1885

1994 ◽  
Vol 13 (1) ◽  
pp. 35-46 ◽  
Author(s):  
Carl-Henry Geschwind
Keyword(s):  
United States ◽  
Lake Superior ◽  
Volcanic Rocks ◽  
The United States ◽  
Substantial Portion ◽  
The West ◽  
The U.S

In the 1860's and 70's, microscopic petrography flourished in Germany, where descriptions and classifications of rocks were highly valued for their own sake. American geologists, however, were more interested in stratigraphical correlations and had relatively little use for petrographical details. Thus, such Americans as George Hawes and Alexis Julien, who attempted to introduce the microscope for purely petrographical work in the early 1870's, had great difficulties in finding an audience. During the late 1870's, however, a number of American geologists-including federal geologists working amongst the volcanic rocks of the West, state geologists mapping in the Lake Superior region, and mining geologists examining the Comstock Lode and the Leadville district-came to appreciate the aid microscopic petrography could provide for stratigraphical correlations. This growing interest led to the hiring of a number of microscopic petrographers around 1880. These petrographers were trained in Germany, where they had imbibed the German passion for petrography for its own sake, but most of them adapted themselves to the American practice of using petrography for stratigraphy. Unlike many of their German counterparts, these American petrographers spent a substantial portion of their time in the field and combined mapping with microscopic examinations to solve stratigraphical problems. Thus, the different scientific cultures of Germany and the U.S. significantly affected the ways in which the petrographic microscope was used.

Distribution of beryllium in unaltered silicic volcanic rocks of the western conterminous United States

1962 ◽  
Vol 57 (6) ◽  
pp. 963-968 ◽  
Author(s):  
R. R. Coats ◽  
P. R. Barnett ◽  
N. M. Conklin
Keyword(s):  
United States ◽  
Volcanic Rocks ◽  
Silicic Volcanic

Peralkaline silicic volcanic rocks of the Western United States

1974 ◽  
Vol 38 (2) ◽  
pp. 803-827 ◽  
Author(s):  
D. C. Noble ◽  
D. F. Parker
Keyword(s):  
United States ◽  
Volcanic Rocks ◽  
Western United States ◽  
Silicic Volcanic

Distribution of fluorine in unaltered silicic volcanic rocks of the western conterminous United States

1963 ◽  
Vol 58 (6) ◽  
pp. 941-951 ◽  
Author(s):  
R. R. Coats ◽  
W. D. Goss ◽  
L. F. Rader
Keyword(s):  
United States ◽  
Volcanic Rocks ◽  
Silicic Volcanic

A late Precambrian rift-related igneous suite in western Newfoundland

1985 ◽  
Vol 22 (11) ◽  
pp. 1727-1735 ◽  
Author(s):  
Harold Williams ◽  
R. T. Gillespie ◽  
Otto Van Breemen
Keyword(s):  
North Atlantic Ocean ◽  
Volcanic Rocks ◽  
The United States ◽  
Granitic Rocks ◽  
Late Precambrian ◽  
The North ◽  
Iapetus Ocean ◽  
Carbonate Sequence ◽  
Silicic Volcanic ◽  
High Level

A granite that yields a U–Pb zircon age of 602 ± 10 Ma is associated with mafic and silicic volcanic rocks and metamorphic equivalents near Deer Lake in western Newfoundland. The granitic rocks are named the Round Pond granite, and the combined granite–volcanic suite is assigned to the Hughes Lake complex. All of the rocks are contained in the Hughes Lake structural slice that occurs above other allochthonous rocks and the autochthonous Cambrian–Ordovician carbonate sequence of western Newfoundland.The Round Pond granite is cut by metadiabase dykes. Mafic volcanic rocks, interpreted as coeval with the dykes, occur along the southeast side of the granite. A thick sequence of arkosic metagreywackes and psammitic to pelitic schists of the Mount Musgrave Group occurs stratigraphically above the mafic volcanic rocks. Regional correlations imply that the Mount Musgrave Group is of late Precambrian – Early Cambrian age, thus setting an upper stratigraphic limit to the age of the Hughes Lake complex.Perthitic and granophyric textures and the chemistry of the Round Pond granite are typical of anorogenic high-level hypersolvus intrusions. Nearby pink silicic volcanic rocks are probably consanguineous with the granite and together with the mafic volcanics form a bimodal suite.Bimodal volcanic suites and related mafic dykes and granitic intrusions imply rift tectonic settings. Occurrences along the west flank of the Appalachian Orogen are equated with the initiation of an ancient continental margin and the opening of an Iapetus Ocean. The 602 ± 10 Ma age of the Round Pond granite dates the rifting in western Newfoundland. Older isotopic ages on similar rocks in the southern Appalachians of the United States suggest a diachronous Precambrian rifting and Iapetus opening that propagated northward, much like the Mesozoic opening of the North Atlantic Ocean.

Party Strength in the United States: Some Corrections

1975 ◽  
Vol 37 (2) ◽  
pp. 641-642 ◽  
Author(s):  
Paul T. David
Keyword(s):  
United States ◽  
The United States ◽  
Party Strength

Correlative microscopy in distrubuted (client/server) computing environments: tools for catalyzing the rapid dissemination of information about the cell biology of the human prostate

1995 ◽  
Vol 53 ◽  
pp. 682-683
Author(s):  
A. Hakam ◽  
J.T. Gau ◽  
M.L. Grove ◽  
B.A. Evans ◽  
M. Shuman ◽  
...  
Keyword(s):  
United States ◽  
Cell Biology ◽  
Tissue Bank ◽  
The United States ◽  
Prostate Adenocarcinoma ◽  
Correlative Microscopy ◽  
Client Server ◽  
Critical Elements ◽  
Transplant Organ

Prostate adenocarcinoma is the most common malignant tumor of men in the United States and is the third leading cause of death in men. Despite attempts at early detection, there will be 244,000 new cases and 44,000 deaths from the disease in the United States in 1995. Therapeutic progress against this disease is hindered by an incomplete understanding of prostate epithelial cell biology, the availability of human tissues for in vitro experimentation, slow dissemination of information between prostate cancer research teams and the increasing pressure to “ stretch” research dollars at the same time staff reductions are occurring.To meet these challenges, we have used the correlative microscopy (CM) and client/server (C/S) computing to increase productivity while decreasing costs. Critical elements of our program are as follows:1) Establishing the Western Pennsylvania Genitourinary (GU) Tissue Bank which includes >100 prostates from patients with prostate adenocarcinoma as well as >20 normal prostates from transplant organ donors.

Digital image acquisition, processing, and analysis in a polymer microscopy laboratory

1994 ◽  
Vol 52 ◽  
pp. 454-455
Author(s):  
Vinod K. Berry ◽  
Xiao Zhang
Keyword(s):  
United States ◽  
Image Analysis ◽  
Digital Image ◽  
Image Acquisition ◽  
Image Transmission ◽  
The United States ◽  
Quantitative Image Analysis ◽  
Quantitative Image

In recent years it became apparent that we needed to improve productivity and efficiency in the Microscopy Laboratories in GE Plastics. It was realized that digital image acquisition, archiving, processing, analysis, and transmission over a network would be the best way to achieve this goal. Also, the capabilities of quantitative image analysis, image transmission etc. available with this approach would help us to increase our efficiency. Although the advantages of digital image acquisition, processing, archiving, etc. have been described and are being practiced in many SEM, laboratories, they have not been generally applied in microscopy laboratories (TEM, Optical, SEM and others) and impact on increased productivity has not been yet exploited as well.In order to attain our objective we have acquired a SEMICAPS imaging workstation for each of the GE Plastic sites in the United States. We have integrated the workstation with the microscopes and their peripherals as shown in Figure 1.

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