Co-management from the top? The roles of policy entrepreneurs and distributive conflict in developing co-management arrangements     

Betsi Beem 《Marine Policy》2007

This research examines attempts to develop co-management arrangements in the Maine lobster and Chesapeake Bay blue crab fisheries. It finds that the attributes of user groups and resources as well as government support are important in facilitating the development of co-management, but are not sufficient. This study highlights that the process of developing institutions for co-management is lengthy and time consuming and that user groups do not necessarily embrace changes to the status quo. I argue that the nature of distributional conflict and the affiliation of policy entrepreneurs account for variation in the development of co-management regimes in these cases.  相似文献   

Petrochemistry of subvolcanic dike swarms associated with the Golden Revenue Au–Cu and the Stoddart Mo–Cu ± W mineralizations (Dawson Range, Yukon Territory, Canada) and implications for ore genesis     

Thierry Bineli Betsi  David Lentz 《Ore Geology Reviews》2011,39(3):134-163

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Subtidal Eelgrass Declines in the Great Bay Estuary,New Hampshire and Maine,USA     

Nora T. Beem  Frederick T. Short 《Estuaries and Coasts》2009,32(1):202-205

Long-term monitoring of eelgrass (Zostera marina L.) beds in the central subtidal portion of the Great Bay Estuary showed declines at both transplanted sites and reference beds. Eelgrass beds transplanted as mitigation for habitat loss from port development reached comparable functions (e.g., primary production, canopy structure) to natural reference sites by the late 1990s, within 6 years of transplanting. Data from 2001 to the present show significant declines in eelgrass parameters (biomass, shoot density, canopy height, leaf area) at all sites, suggesting that these declines are the result of an estuary-wide factor.  相似文献   

Genesis of the Au–Bi–Cu–As, Cu–Mo ± W, and base–metal Au–Ag mineralization at the Mountain Freegold (Yukon, Canada): constraints from Ar–Ar and Re–Os geochronology and Pb and stable isotope compositions     

Thierry Bineli Betsi  David Lentz  Massimo Chiaradia  Kurt Kyser  Robert A. Creaser 《Mineralium Deposita》2013,48(8):991-1017

The genesis of mineralized systems across the Mountain Freegold area, in the Dawson Range Cu–Au?±?Mo Belt of the Tintina Au province was constrained using Pb and stable isotope compositions and Ar–Ar and Re–Os geochronology. Pb isotope compositions of sulfides span a wide compositional range (²⁰⁶Pb/²⁰⁴Pb, 18.669–19.861; ²⁰⁸Pb/²⁰⁴Pb, 38.400–39.238) that overlaps the compositions of the spatially associated igneous rocks, thus indicating a magmatic origin for Pb and probably the other metals. Sulfur isotopic compositions of sulfide minerals are broadly similar and their δ³⁴S (Vienna-Canyon Diablo Troilite (V-CDT)) values range from ?1.4 to 3.6 ‰ consistent with the magmatic range, with the exception of stibnite from a Au–Sb–quartz vein, which has δ³⁴S values between ?8.1 and ?3.1 ‰. The δ³⁴S values of sulfates coexisting with sulfide are between 11.2 and 14.2 ‰; whereas, those from the weathering zone range from 3.7 to 4.3 ‰, indicating supergene sulfates derived from oxidation of hypogene sulfides. The δ¹³C (Vienna Peedee Belemnite (VPDB)) values of carbonate range from ?4.9 to 1.1 ‰ and are higher than magmatic values. The δ¹⁸O (V-SMOW) values of magmatic quartz phenocrysts and magmatic least-altered rocks vary between 6.2 and 10.1 ‰ and between 5.0 and 10.1 ‰, respectively, whereas altered magmatic rocks and hydrothermal minerals (quartz and magnetite) are relatively ¹⁸O-depleted (4.2 to 7.9 ‰ and ?6.3 to 1.5 ‰, respectively). Hydrogen isotope compositions of both least-altered and altered igneous rock samples are D-depleted (from ?133 to ?161 ‰ Vienna-Standard Mean Ocean Water (V-SMOW)), consistent with differential magma degassing and/or post-crystallization exchange between the rocks and meteoric ground water. Zircon from a chlorite-altered dike has a U–Pb crystallization age of 108.7?±?0.4 Ma; whereas, the same sample yielded a whole-rock Ar–Ar plateau age of 76.25?±?0.53 Ma. Likewise, molybdenite Re–Os model ages range from 75.8 to 78.2 Ma, indicating the mineralizing events are genetically related to Late Cretaceous volcano-plutonic intrusions in the area. The molybdenite Re–Os ages difference between the nearby Nucleus (75.9?±?0.3 to 76.2?±?0.3 Ma) and Revenue (77.9?±?0.3 to 78.2?±?0.3 Ma) mineral occurrences suggests an episodic mineralized system with two pulses of hydrothermal fluids separated by at least 2 Ma. This, in combination with geological features suggest the Nucleus deposit represents the apical and younger portion of the Revenue–Nucleus magmatic-hydrothermal system and may suggest an evolution from the porphyry to the epithermal environments.  相似文献   

Impact of storms and earthquakes on industrial installations – New risk control approaches required?     

H. Beem  R. Fendler  W. B. Krätzig 《Natural Hazards》2008,46(2):243-256

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The Nucleus Deposit: Superposed Au–Ag–Bi–Cu Mineralization Systems at Freegold Mountain,Yukon, Canada          下载免费PDF全文

Thierry Bineli Betsi  David R. Lentz  Chris Mcfarlane 《Resource Geology》2016,66(4):419-454

In this paper we present titanite U–Pb (both single crystal CA ID‐TIMS and in situ LA ICP‐MS) data, coupled with ore and gangue mineralogy and geochemical (both lithogeochemistry and microanalysis) data from the Nucleus Au–Ag–Bi–Cu deposit, in the Yukon (Canada) portion of the Tintina Au province. Arsenic‐bearing Au–Ag–Bi–Cu mineralization at Nucleus consists of two distinct styles of mineralization including: (i) reduced Au skarn and sulfide replacement; and (ii) a relatively shallow‐emplaced (as supported by textures and temperature of formation), vein‐controlled mineralization occurring mainly as veins and veinlets of various shapes (sheeted, single, stockworks, and crustiform), breccias, and disseminations. Whereas Au, Bi, and Cu mineralization from skarn is associated with hydrous retrograde alteration phases (actinolite, ferro‐actinolite, hastingsite, cannilloite, and hornblende), numerous alteration types are associated with the vein‐controlled style of mineralization and these include: biotite, phyllic, argillic, propylitic, carbonate, and quartz (silicification) alterations. The mineralization–alteration processes took place over a wide temperature range that is bracketed between 340 and 568°C, as indicated by chlorite and arsenopyrite geothermometers. The Au‐rich Nucleus deposit is characterized by anomalously high content of As and Bi (as much as 1 %), and whereas Au moderately correlates with Bi (r = 0.40) in the skarn mineralization style (where native Au is spatially associated with native Bi and Bi‐bearing sulfides), the two elements correlate poorly (r = 0.14) in the vein‐controlled type, in which native Bi‐ and Bi‐sulfide‐bearing veins are locally observed. Sphalerite from the vein‐controlled mineralized type is Fe‐rich (9.92–10.54 mol % FeS) indicative of low sulfidation conditions, as well as high temperature, with the latter further supported by arsenopyrite geothermometry (up to 491°C), low Ag content (3–7 wt.%) in Au, and the high gold fineness (926–964). Whereas molybdenite Re–Os ages from quartz‐molybdenite veins range from 75.8 to 76.2 ± 0.3 Ma, titanite from the skarn type mineralization recorded CA ID‐TIMS and LA ICP‐MS U–Pb ages of 182.6 ± 2.4 Ma and 191.0 ± 1.5 Ma, respectively, thus precluding any genetic link between the two spatially associated styles of mineralization from the Nucleus deposit area. The Au–Ag–Bi–Cu Nucleus deposit is therefore regarded as a superposed system in which two mineralization types, without any petrogenetic relationship, overlapped, possibly with remobilization of early‐formed mineralization.  相似文献