24 research outputs found

    Granitoid rocks and associated coper skarn, Whycocomagh Mountain, Cape Breton Island, Nova Scotia

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    Mineralized (Fe-Cu-W-Mo) skarn in the Whycocomagh Mountain area is associated with a small pluton of Devonian (402±20 Ma) age, which intruded predominantly metasedimentary rocks of the Hadrynian George River Group. The pluton consists largely of granite porphyry with a marginal granodiorite to diorite zone, and minor porphyritlc granodiorite to monzodiorite dykes and pegmatite. The suite is calc-alkalic with I-type characteristics. Although weakly mineralized, the Whycocomagh Mountain pluton has features typical of plutons associated with porphyry-type Cu-Mo deposits. Calc-silicate rocks derived from marbles of the George River Group are the chief hosts for magnetlte ± chalcopyrlte ± scheelite ± molybdenite ± pyrite which occur in veinlets along fractures and as disseminated grains In adjacent alteration envelopes. Characteristics of the pluton and the skarn minerals suggest that the deposit is a copper skarn. RÉSUMÉ Un skarn minéralise (Fe-Cu-W-Mo), situe dans la région de la montagne Whycocomagh, est associé à une petite intrusion ignée d'âge Dévonien (402±20 m.a.) qui pénétre des roches, principalement des métasédiments, du groupe George River (Hadrynien). Le pluton consiste surtout en un granite porphyrique accompagne d'une zone marginale (granodiorite à diorite), de dykes mineurs (granodiorite à monzodiorite porphyrique) et de pegmatite. L'ensemble est calco-alcalln et de "type 1". Blen que faiblement minéralise, le pluton Whycocomagh Mountain possède lea caractérlstiques typiques des plutons associés aux dépôts porphyrlques de type Cu-Mo. Les calco-sflicates dérives des marbres du groupe George River sont les notes principaux du cortege for magnétite ± chalcopyrlte ± scheelite ± molybdenite ± pyrite que L’on retrouve dans des veinules le long des fractures et disséminés dans les enveloppes d'alteratlon volsines. Les caractérlstiques du pluton ainsi que la minéralogle du skarn font croire qu'il s'agit d'un dépôt de skarn cuprifère. (Tradult par le Journal

    Coastal Geology and Geomorphology of Cape Cod - An Aerial and Ground View

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    Guidebook for field trips to the Boston area and vicinity : 68th annual meeting, New England Intercollegiate Geological Conference, October 8-10, 1976: Trip A-10; B-1

    Shoaling of nonlinear internal waves in Massachusetts Bay

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    Author Posting. © American Geophysical Union, 2008. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 113 (2008): C08031, doi:10.1029/2008JC004726.The shoaling of the nonlinear internal tide in Massachusetts Bay is studied with a fully nonlinear and nonhydrostatic model. The results are compared with current and temperature observations obtained during the August 1998 Massachusetts Bay Internal Wave Experiment and observations from a shorter experiment which took place in September 2001. The model shows how the approaching nonlinear undular bore interacts strongly with a shoaling bottom, offshore of where KdV theory predicts polarity switching should occur. It is shown that the shoaling process is dominated by nonlinearity, and the model results are interpreted with the aid of a two-layer nonlinear but hydrostatic model. After interacting with the shoaling bottom, the undular bore emerges on the shallow shelf inshore of the 30-m isobath as a nonlinear internal tide with a range of possible shapes, all of which are found in the available observational record.A. Scotti began this project as a Postdoctoral Scholar at the Woods Hole Oceanographic Institution, with support from the Johnson Foundation and the USGS. Further support was provided to Scotti by the Office of Naval Research under grants N00014-01-1-0172, N00014-03-1-0553, and N00014-05-1-0361, and by NSF under grant OCE 07-29636. R. Beardsley was supported by ONR under grants N00014-98-1- 0059, N00014-00-1-0210, and the Smith Chair in Coastal Physical Oceanography. J. Pineda was supported by ONR under grants N00014-01-1-0172, and by a WHOIOcean Life Institute Fellowship

    Flow and nutrient dynamics in a subterranean estuary (Waquoit Bay, MA, USA) : field data and reactive transport modeling

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    Author Posting. © Elsevier B.V., 2008. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Geochimica et Cosmochimica Acta 72 (2008): 3398-3412, doi:10.1016/j.gca.2008.04.027.A two-dimensional (2D) reactive transport model is used to investigate the controls on nutrient (NO3-, NH4+, PO4) dynamics in a coastal aquifer. The model couples density dependent flow to a reaction network which includes oxic degradation of organic matter, denitrification, iron oxide reduction, nitrification, Fe2+ oxidation and sorption of PO4 onto iron oxides. Porewater measurements from a well transect at Waquoit Bay, MA, USA indicate the presence of a reducing plume with high Fe2+, NH4+, DOC (dissolved organic carbon) and PO4 concentrations overlying a more oxidizing NO3--rich plume. These two plumes travel nearly conservatively until they start to overlap in the intertidal coastal sediments prior to discharge into the bay. In this zone, the aeration of the surface beach sediments drives nitrification and allows the precipitation of iron oxide, which leads to the removal of PO4 through sorption. Model simulations suggest that removal of NO3- through denitrification is inhibited by the limited overlap between the two freshwater plumes, as well as by the refractory nature of terrestrial DOC. Submarine groundwater discharge is a significant source of NO3- to the bay.This research was funded by the Netherlands Organisation for Scientific Research (NWO) and WHOI Guest Student Program (C. Spiteri), the Royal Netherlands Academy of Arts and Sciences (KNAW) and the Netherlands Organization for Scientific Research (NWO VIDI-grant) (C.P. Slomp), the US National Science Foundation NSF-OCE0095384 and NSF-OCE0425061 (M.A. Charette) and the Georgia Sea Grant of the National Sea Grant College Program of the U.S. Department of Commerce’s National Oceanic and Atmospheric Administration under NOAA Grant #NA04OAR4170033 (C. Meile)

    Understanding Behavioral Antitrust

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    Branching Bandits: A Sequential Search Process with Correlated Pay-Offs.

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    This paper presents a model of a sequential search process for the best outcome of many multi-stage projects. The branching structure of the search environment is such that the payoffs to various actions are correlated; nevertheless, it is shown that the optimal strategy is given by a simple reservation price rule

    Imaging renal masses and staging renal tumours

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    Local bus deregulation and timetable instability

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