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1.
《Geoforum》2017
Reducing Emissions from Deforestation and forest Degradation (REDD+) is envisioned as a performance-based incentive to influence forest use behavior and governance towards the preservation and management of forests. In relatively forest-rich Lao PDR, the policy space that REDD+ planners are attempting to navigate is populated by enduring political and economic interests that affect the country’s forest estate. A further layer to the problem of REDD+ planning is the tension between often expert-driven, externally proposed solutions; national ownership over interventions; and the extent of political will to take action to reform currently unsustainable patterns of forest and forest land exploitation. This paper draws from a series of semi-structured interviews conducted in 2013–2014, to develop a political and institutional analysis of the limitations to the effectiveness of REDD+ in steering towards a lower forest-derived emissions trajectory in Lao PDR. While internationally-driven projects follow long-standing national objectives to varying degrees, it remains unclear how REDD+ can target main drivers of deforestation in the absence of a more politically engaged and nationally-owned planning process, that also challenges the prevailing logic of avoiding these drivers. Despite the importance of improving domestic ownership over REDD+, this would arguably be of limited impact unless oriented towards transformational change that would seek to overcome political and economic barriers to avoided deforestation. Stronger ownership could be developed via more mutually driven REDD+ planning, while tackling main drivers of deforestation necessitates as a starting point the engagement of powerful actors that have so far been absent from REDD+ debate. 相似文献
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Akhlaq Amin Wani P. K. Joshi Ombir Singh Rajesh Kumar V. R. S. Rawat Bilal A. Khaki 《Environmental Earth Sciences》2017,76(16):573
Carbon emissions from forests have decreased in the past decade due to conservation efforts, however majority of carbon losses suffered in the past went unnoticed until the role of forests in mitigating climate change was realized. Forestry sector in developing countries is recognized as one of the largest and low cost mitigation options to address climate change. The present study was conducted to assess the multi-temporal biomass carbon mitigation in the temperate forests of western Himalaya using satellite (Landsat MSS, TM, ETM+) and forest inventory data. Forest type density mapping was done through on-screen visual interpretation of satellite data. After conducting preliminary survey in 2009, 45 quadrats (0.1 ha) were laid in six forest types for collecting field inventory data viz., diameter at breast height, tree height, slope and aspect. Biomass carbon (t ha?1) was estimated for different forest types with different crown densities (open with 10–40% crown density and closed with >40%) using recommended regression equations, ratios and factors. A decreasing trend of carbon (145.13–134.87 mt) was observed over the period of time. Temporal biomass carbon dynamics was analyzed for REDD+ opportunities. The temporal variation of carbon observed was found to be more useful for claiming benefits under negative options (deforestation and forest degradation) of REDD+. The study doesn’t take actual conversions to CO2 into account. However, the findings are useful in establishing baseline emissions through temporal carbon losses. Further, the study helps in identification of location specific socio-economic drivers of losses that can be used for appropriate mitigation interventions. 相似文献
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《Geoforum》2017
In Vietnam, initial programs to Reduce Emissions from Deforestation and Forest Degradation (REDD+) have proliferated through international finance and new governance regimes for climate change mitigation. National capacity and legal frameworks have been adjusted to make the country eligible for REDD+ financing. In some local areas, activities have been implemented to ‘produce’ carbon credits intended for the international voluntary carbon market. Through a case study of a pilot REDD+ project in the Central Highlands of Vietnam, we examine how REDD+ has intersected with property rights institutions and agrarian change to influence changing property relations and commodity markets. Our findings show that REDD+ implemented through state and local institutions has articulated with the local political economy to coproduce conditions that embody local norms, needs, and desires. Specifically, local actors negotiate state-sanctioned tenurial instruments used for REDD+ governance, not for the purposes of carbon sequestration but instead in order to reassert their rights to land and forest for the cultivation of boom crops—the antithesis of REDD+ objectives. In the fine balancing act of adjusting local forestland holdings, REDD+ implementation has effectively facilitated increased opportunities for upland villagers to strategically claim land titles from local political authorities in the form of communal land certificates for forests called ‘Red Books’. In securing communal Red Books, villagers redefine or co-constitute the purpose of REDD+ to secure land for cash crop and commercial timber production. As with other forms of environmental governance, REDD+ is thus co-constituted locally in line with state and local institutions and histories and present day realities. 相似文献
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《Geoforum》2015
A rapidly growing literature interrogates the social and economic impacts of various Reducing Emissions from Deforestation and Forest Degradation (REDD+) schemes in Sub-Saharan Africa. Less often, however, have scholars examined the necessary corollary of such initiatives; that is, both new and enhanced law enforcement initiatives to combat the global trade in illegal forest products and secure property rights to conserved forests. Drawing upon recent consultative experiences for relevant multinational agencies in East Africa, we critically analyze the emergent features of this additional ‘dark side’ of REDD+, highlighting in particular both its potential for ‘leakage’ effects on adjacent jurisdictions and deleterious implications for forest-dependent communities. Specifically, we highlight the ways in which such activities threaten to conflate illegal with informal trade in forest products; the ways in which they are potentially ill-suited for addressing the trade in charcoal as opposed to the trade in timber; and the incentives that they may provide for states to further marginalize indigenous forest-dwelling populations in the region. In doing so, we argue that this nascent synthesis of REDD+ and transnational law enforcement threatens to contribute significantly and regressively to the broader securitization of conservation in Sub-Saharan Africa and elsewhere. 相似文献
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Thin- to medium-bedded, stratiform calc-silicate deposits (banded skarns) are a peculiar, but important, component of the supracrustal successions in the Palaeoproterozoic Bergslagen mining district of central Sweden. They are referred to as ??skarn-banded leptites?? in the literature and are common in areas and at stratigraphic levels that contain iron oxide and base metal sulphide deposits. The stratigraphic hanging wall of the stratabound Ryllshyttan Zn?CPb?CAg + magnetite deposit at Garpenberg, contains approximately 100?C150?m of interbedded aluminous skarn beds and rhyolitic ash-siltstones. The skarn beds are mineralogically variable and dominantly composed of grandite, spessartine, epidote, actinolite, quartz, clinopyroxene, and locally magnetite. Integrated field-mapping, and whole-rock lithogeochemical, microscopic and mineral chemical analyses suggest that the stratiform skarn beds are the products of at least two discrete hydrothermal events and subsequent metamorphism. The first event comprised accumulation in a quiescent subaqueous environment, below wave base, of calcareous and ferruginous sediments rich in Fe, Mn, Ca, and Mg. These chemical sediments were deposited concurrently with rhyolitic ash-silt sedimentation, thus forming a (now metamorphosed) laminated calcareous Fe formation with both a detrital rhyolitic component and rhyolitic siltstone interbeds. Positive Eu-anomalies and negative Ce-anomalies for normalized rare earth element analyses of skarn beds suggest that the iron may have been derived from exhalation of hot and reduced hydrothermal fluids, which upon mixing with more oxidized seawater, precipitated Fe oxides and/or carbonates that settled from suspension to the seafloor. The size of the positive Eu-anomalies of the chemical sediments are modified by the content of rhyolitic volcaniclastic material, which has a negative Eu anomaly, such that positive Eu-anomalies are only observed in skarn beds that possess a minor volcaniclastic component. Subsequently, the calcareous Fe formations were subjected to post-depositional alteration by hydrothermal fluids, locally yielding more manganoan and magnesian assemblages. The Mn-alteration is manifested by lateral gradations from epidote-grandite-clinopyroxene±magnetite rocks into significantly more Mn-rich quartz-spessartine rocks and massive andradite rocks over distances of less than 10?cm within individual skarn beds. Magnesian alteration is manifested by the development of discordant zones of pargasite para-amphibolites and formation of stratiform pargasite rocks texturally similar to the interlaminated grandite-epidote-ferroan diopside rocks. The latter increase in abundance towards the Ryllshyttan deposit and are associated with pre-metamorphic/pre-tectonic K?CMg?CFe±Si alteration (now biotite-phlogopite-garnet-cordierite-pargasite rocks) that is related to base metal mineralization. The zone of Mn- and Mg-altered skarn beds extends beyond the zone of pervasive K?CMg?CFe±Si alteration around Ryllshyttan. This suggests that the skarn bed progenitors, or their sedimentary contacts against rhyolitic ash-siltstones, acted as conduits to outflowing hydrothermal fluids. The chemical and mineralogical imprint, imposed on affected beds by alteration, may serve as indicators of proximity to intense K?CMg?CFe±Si alteration envelopes around other base metal sulphide deposits in Bergslagen. The last recorded event comprised syn-tectonic veining of competent massive andradite skarn beds. The veins contain quartz-albite-epidote-ferroan diopside-actinolite assemblages. 相似文献
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GREW EDWARD S.; PERTSEV NIKOLAY N.; YATES MARTIN G.; CHRISTY ANDREW G.; MARQUEZ NICHOLAS; CHERNOSKY JOSEPH V. 《Journal of Petrology》1994,35(5):1275-1293
Sapphirine occurs with humite-group minerals and forsteritein Precambrian amphibole-facies rocks at Kuhi-lal, SW PamirMountains, Tajikistan, a locality also for talc+kyanite magnesiohornblendewhiteschist. Most of these sapphirine-bearing rocks are graphiticand sulfidic (pyrite and pyrrhotite) and contain enstatite,clinohumite or chondrodite, spinel, rutile, gedrite, and phlogopite.A phlogopite schist has the assemblage with XFe = Fe/(Fe+Mg)increasing as follows: chlorite (0-003)<phlogopite (0.004–0.005)sapphirine (0.004–0.006) enstatite (0-006)forsterite (0-006–0-007)<spinel (0-014). This assemblage includes the incompatiblepair sapphirine+forsterite, but there is no textural evidencefor reaction. In one rock with clinohumite, XFe increases asfollows: clinohumite (0-002) <sapphirine (0-003) <enstatite(0-004–0-006) <spinel (0-010). Ion microprobe and wet-chemicalanalyses give 0-57–0-73 wt.% F in phlogopite and 0-27wt.% F in chlorite in the phlogopite schist; 0-04, 1.5–1.9,and 4.4 wt.% F in forsterite, clinohumite, and chondrodite,respectively; and 0-0-09 wt.% BeO and 0-05–0-21 wt.% B2O3in sapphirine. Stabilization of sapphirine+clinohumite or sapphirine+chondroditeinstead of sapphirine+phlogopite is possible at high F contentsin K-poor rocks, but minor element contents appear to be toolow to stabilize sapphirine as an additional phase with forsterite+enstatite+spinel.Although sapphirine+forsterite is metastable relative to spinel+enstatitein experiments conducted at aH2O=1 in the MgO-Al2O3-SiO2-H2Osystem, it might be stabilized at aH2O0.5, P4 kbar, T650–700C.Textures in the Kuhi-lal whiteschists suggest a polymetamorphicevolution in which the rocks were originally metamorphosed atT650C, P 7 kbar, conditions under which sapphirine+clinohumiteand sapphirine+chondrodite are inferred to have formed, andsubsequently affected by a later event at lower P, similar T,and lower aH2O. The latter conditions were favorable for sapphirine+forsteriteto form in a rock originally containing chlorite+forsterite+spinel+enstatite. 相似文献
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Henrik Friis Adrian A. Finch C. Terry Williams John M. Hanchar 《Physics and Chemistry of Minerals》2010,37(6):333-342
The photoluminescence properties of synthetic zircon, ZrSiO4, doped with REE3+ (REE = Pr, Sm, Eu, Gd, Dy, Ho, Er) were investigated using combined excitation and emission spectroscopy. All samples showed
luminescence characteristics of intra-ion energy transitions, similar to other lanthanide-doped materials. However, the relative
intensities were dependent on the energy of excitation and the presence of charge-transfer bands were inferred from excitation
spectra. From the data, we conclude that the lanthanides in zircon occur in more than one type of coordination. Energy transfer
between different lanthanides was observed in some co-doped samples and emissions that were unassigned in previous studies
have been assigned to specific lanthanides based on excitation spectroscopy. 相似文献
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Haitaite-(La), (La, Ce)(U4+, U6+, Fe2+)(Fe3+, Al)2(Ti, Fe2+, Fe3+)18O38, is a new member of the crichtonite group. It is named after the Haita Village in the Miyi County of Sichuan Province, China, where the mineral was discovered. The mineral occurs as black opaque centimeter-sized aggregates in the external contact zone between the Neoproterozoic (~800 Ma) alkali feldspar granite and the Mesoproterozoic (~1700 Ma) micaschist. In the studied sample, haitaite-(La) is associated with other minerals, including ilmenite, magnetite, rutile, zircon, brannerite and uraninite. The new mineral is a black, metallic phase and has a Mohs hardness of 6, with a density of 4.99 g/cm3 (calculated) and 5.03 g/cm3 (measured). Haitaite-(La) is opaque in transmitted light and grayish-white under reflected light, with a reflectivity between 22.5% and 16.42% in the 400–700 nm band (SiC, in the air). The compositions of the mineral were measured by EPMA, the U4+/U6+ ratio was determined by X-ray photoelectron spectroscopy and the Fe2+/Fe3+ ratio was determined by M?ssbauer spectroscopy. Haitaite-(La) is trigonal, belongs to R3ˉ and has unit-cell parameters a = 10.3678(5) ?, c = 20.8390(11) ?, V = 1939.9(2) ?3, Z = 3. The crystalline structure is composed of octahedra with 9 layers of close-packed octahedra (M1, M3, M4, M5), tetrahedra (M2) and contains large 12-coordinated M0 sites. 相似文献
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富含Na+ 、Ca2+、Al3+、Cr3+蒙脱石对垃圾渗滤液中有机物的吸附 总被引：5，自引：2，他引：5
由于层间含有高价态金属阳离子的蒙脱石对特定有机物的吸附能力可大大增强,故分别用层间含有Na+、Ca2+、Al3+和Cr3+的蒙脱石对垃圾渗滤液中的有机物进行吸附实验,研究它们吸附苯酚、二甲苯和COD的能力及离子形态对吸附效果的影响.结果表明,含高价金属阳离子的蒙脱石对苯酚和COD的吸附能力较高,吸附能力由小到大的顺序为Na+<Ca2+<Al3+<Cr3+蒙脱石;各种类型蒙脱石对二甲苯的吸附能力相对较低,并且没有一定的规律可循.并对氢键吸附机制进行了探讨. 相似文献
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Paolo Orlandi Cristian Biagioni Marco Pasero Marcello Mellini 《Physics and Chemistry of Minerals》2013,40(3):239-249
The new mineral species lavoisierite, ideally Mn2+ 8[Al10(Mn3+Mg)][Si11P]O44(OH)12, has been discovered in piemontite-bearing micaschists belonging to the Piedmontese Nappe from Punta Gensane, Viù Valley, Western Alps, Italy. It occurs as yellow-orange acicular to prismatic-tabular crystals up to a few millimeters in length, with white streak and vitreous luster, elongated along [010] and flattened on {001}. Lavoisierite is associated with quartz, “mica,” sursassite, piemontite, spessartine, braunite, and “tourmaline.” Calculated density is 3.576 g cm?3. In plane-polarized light, it is transparent, pleochroic, with pale yellow parallel to [010] and yellow-orange normal to this direction; extinction is parallel and elongation is positive. Birefringence is moderate; the calculated average refraction index n is 1.750. Lavoisierite is orthorhombic, space group Pnmm, with a 8.6891(10), b 5.7755(3), c 36.9504(20) Å, V 1854.3(2) Å3, Z = 2. Calculated main diffraction lines of the X-ray powder diffraction pattern are [d in Å, (I), (hkl); relative intensities are visually estimated]: 4.62 (m) (112), 2.931 (vs) (1110), 2.765 (s) (1111), 2.598 (s) (310), 2.448 (ms) (028). Chemical analyses by electron microprobe give (in wt%) P2O5 2.08, V2O5 0.37, SiO2 34.81, TiO2 0.13, Al2O3 22.92, Cr2O3 0.32, Fe2O3 0.86, Mn2O3 6.92, MnO 19.09, MgO 5.73, CaO 1.94, Na2O 0.01, H2O 5.44, sum 100.62 wt%. H2O content was calculated from structure refinement. The empirical formula, based on 56 anions, is (Mn 5.340 2+ Mg1.810Ca0.686Na0.006)Σ=7.852(Al8.921Mn 1.739 3+ Mg1.010Fe 0.214 3+ Cr0.084Ti0.032)Σ=12.000(Si11.496P0.582V0.081)Σ=12.159O43.995(OH)12.005. The crystal structure of lavoisierite was solved by direct methods and refined on the basis of 1743 observed reflections to R 1 = 4.6 %. The structure is characterized by columns of edge-sharing octahedra running along [010] and linked to each other by means of [SiO4], [Si2O7], and [Si3O10] groups. Lavoisierite, named after the French chemist and biologist Antoine-Laurent de Lavoisier (1743–1794), displays an unprecedented kind of structure, related to those of “ardennite” and sursassite. 相似文献
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雪玉洞岩溶地下水、地表水Ca2+、Mg2+、Sr2+变化特征研究 总被引：2，自引：1，他引：1
通过2011年对重庆丰都雪玉洞洞内滴水和地下河河水,上覆岩层中出露的表层岩溶泉水和雪玉洞附近龙河河水等不同类型水中Ca2+、Mg2+、Sr2+浓度及Mg/Ca、Sr/Ca值的研究,发现不同水的Ca2+、Mg2+、Sr2+随外界降水条件的改变而出现明显变化。表层岩溶泉水Ca2+变化能够敏感反应外界降水条件改变,滴水对外界降雨的反应滞后接近1个月,地下河Ca2+可以反应雨季和旱季的变化,地表河水Ca2+全年比较稳定,但是对特殊干旱天气有显著响应。2011年不同类型水的Mg2+、Sr2+全年变化趋势基本一致,在降水较多的3、5、10月呈低值,在其他降水较少的月份浓度相对较高。各离子的这种变化特征主要是受到稀释效应、CO2效应以及所在地层的岩性的影响。雪玉洞不同类型水的Mg/Ca、Sr/Ca值呈现出滴水>地表河>地下河>表层岩溶泉的特点,反映出不同类型水在含水介质中滞留时间的长短,并且Mg/Ca、Sr/Ca值在降水较多的月份降低,在降水较少的月份升高;受碳酸钙的前期沉淀和运移路径差异的影响,不同类型水的Mg/Ca、Sr/Ca值变化稍有不同。因此,不同类型水的离子变化及其比值对外界降水条件变化的响应特征和时间的不同,决定了在利用元素及其比值反映外界环境变化时也要区别对待。 相似文献
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"互联网+"代表一种新的经济形态,即充分发挥互联网在生产要素配置中的优化和集成作用,将互联网的创新成果深度融合于经济社会各领域之中,提升创新力和生产力。在化石保护工作不断推进的形势下,将"互联网+"的理念引入到化石工作领域,建设数字化石,让信息网络技术服务于化石科研、科普和保护管理工作是大势所趋。本文从实施"互联网+化石保护行动计划"所涉及的技术和管理问题入手,探讨建设国家重点保护化石产地和重要标本数字化平台的基本条件,并对数字化石未来在服务科研、科普教育和保护管理等领域的前景进行展望。 相似文献
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在软水区用人造金刚石钻进硅酸盐、铝硅酸盐地层,常见润滑冲洗液中岩粉不沉淀现象,致使冲洗液润滑性大幅度降低。根据室内测定,冲洗液的润滑性与岩粉浓度有如表1所示的关系。 相似文献