Contrasting PT paths within the Barchi-Kol UHP terrain (Kokchetav Complex): Implications for subduction and exhumation of continental crust

The Barchi-Kol terrain is a classic locality of ultrahigh-pressure (UHP) metamorphism within the Kokchetav metamorphic belt. We provide a detailed and systematic characterization of four metasedimentary samples using dominant mineral assemblages, mineral inclusions in zircon and monazite, garnet zonation with respect to major and trace elements, and Zr-in-rutile and Ti-in-zircon temperatures. A typical diamond-bearing gneiss records peak conditions of 49 ± 4 kbar and 950–1000 °C. Near isothermal decompression of this rock resulted in the breakdown of phengite associated with a pervasive recrystallization of the rock. The same terrain also contains mica schists that experienced peak conditions close to those of the diamond-bearing rocks, but they were exhumed along a cooler path where phengite remained stable. In these rocks, major and trace element zoning in garnet has been completely equilibrated. A layered gneiss was metamorphosed at UHP conditions in the coesite field, but did not reach diamond-facies conditions (peak conditions: 30 kbar and 800–900 °C). In this sample, garnet records retrograde zonation in major elements and also retains prograde zoning in trace elements. A garnet-kyanite-micaschist that reached significantly lower pressures (24 ± 2 kbar, 710 ± 20 °C) contains garnet with major and trace element zoning. The diverse garnet zoning in samples that experienced different metamorphic conditions allows to establish that diffusional equilibration of rare earth element in garnet likely occurs at ~900–950 °C. Different metamorphic conditions in the four investigated samples are also documented in zircon trace element zonation and mineral inclusions in zircon and monazite. U-Pb geochronology of metamorphic zircon and monazite domains demonstrates that prograde (528–521 Ma), peak (528–522 Ma), and peak to retrograde metamorphism (503–532 Ma) occurred over a relatively short time interval that is indistinguishable from metamorphism of other UHP rocks within the Kokchetav metamorphic belt. Therefore, the assembly of rocks with contrasting P-T trajectories must have occurred in a single subduction-exhumation cycle, providing a snapshot of the thermal structure of a subducted continental margin prior to collision. The rocks were initially buried along a low geothermal gradient. At 20–25 kbar they underwent near isobaric heating of 200 °C, which was followed by continued burial along a low geothermal gradient. Such a step-wise geotherm is in good agreement with predictions from subduction zone thermal models.

Marine Spatial Planning is coming to an ocean near you

There are too many conflicting uses of the ocean in a time where resources are rapidly dwindling. Marine Spatial Planning is catching on globally, and may soon come to Long Island Sound, but it may be difficult to decide who gets to do what, where.

Sustaining the Economic Rent of Oceanic Resources: The Case of Marine Protected Areas

This paper investigates economic aspects of marine protected areas (MPAs) that are closely related to the underlying marine biota. Many marine scientists recognize that enough is now known about the marine biology for the scientific siting of MPAs to protect marine environments that create associated economic values. Marine scientists have identified several objectives of MPAs. These include protection of genetic and biodiversity, increase in population levels and structures (e.g., age, size, fecundity), enrichment of ecosystems by promoting species interactions, and the protection of continental shelf landscapes from invasive human actions. Indeed, some marine scientists and fisheries economists view MPAs as an 'insurance policy' against over-fishing and other human uses of oceanic resources that have damaged so many of the world's fisheries. The economic analysis presented here pays attention to optimal zoning, policies to maintain sustainable economic rents, and the optimal policing of MPAs.

(Table 3) Chemical analyses from DSDP Holes 22-214, 22-215 and 22-216 in the Indian Ocean

The basalts and oceanic andesites from the aseismic Ninetyeast Ridge display trachytic, vesicular and amygdaloidal textures suggesting a subaerial volcanic environment. The normative composition of the Ninetyeast Ridge ranges from olivine picriteto nepheline-normative alkaline basalt, suggesting a wide range of differentiation. This is further supported by the fractionation-differentiation trends displayed by transition metal trace elements (Ni, Cr, V and Cu). The Ninetyeast Ridge rocks are enriched in rare earth (RE) and large ion lithophile (LIL) elements and Sr isotopes (0.7043-0.7049), similar to alkali basalts and tholeiites from seamounts and islands, but different from LIL-element-depleted tholeiitic volcanic rocks of the recent seismic mid-Indian oceanic ridge. The constancy of 87Sr/86Sr ratios for basalts and andesites is compatible with a model involving fractional crystallization of mafic magma. The variation of 87Sr/86Sr ratios between 0.97 and 2.79 may possibly be explained in terms of a primordial hot mantle and/or chemically contrasting heterogeneous mantle source layers relatively undepleted in LIL elements at different periods in the geologic past. In general, the Sr isotopic data for rocks from different tectonic environments are consistent with a "zoning-depletion model" with systematically arranged alternate alkali-poor and alkali-rich layers in the mantle beneath the Indian Ocean.

(Table 1) Heavy-mineral analyses for DSDP Leg 67 Holes from electron microprobe

Heavy and light minerals were examined in 29 samples from Sites 494, 498, 499, 500, and 495 on the Deep Sea Drilling Project Leg 67 Middle America Trench transect; these sites represent lower slope, trench, and oceanic crust environments off Guatemala. All samples are Quaternary except those from Hole 494A (Pliocene) and Hole 498A (Miocene). Heavy-mineral assemblages of the Quaternary sediments are characterized by an immature pyroxene-amphibole suite with small quantities of olivine and epidote. The Miocene sediments yielded an assemblage dominated by epidote and pyroxene but lacking olivine; the absence of olivine is attributed to selective removal of the most unstable components by intrastratal solution. Light-mineral assemblages of all samples are predominantly characterized by volcanic glass and plagioclase feldspar. The feldspar compositions are compatible with andesitic source rocks and frequently exhibit oscillatory zoning. The heavy- and light-mineral associations of these sediments suggest a proximal volcanic source, most probably the Neogene highland volcanic province of Guatemala. Sand-sized components from Site 495 are mainly biogenic skeletons and volcanic glass and, in one instance (Section 495-5-3), euhedral crystals of gypsum.

Geochemistry of minerals from lavas of ODP Leg 135 holes

We use Nomarski differential interference contrast imaging to reveal the wealth of complex detail in plagioclase zoning for selected samples from Sites 834, 839, and 841. All sites contain some plagioclase with the very complex internal core zoning, convolute zoning, or very fine-scale euhedral oscillatory zoning of the sort generally considered typical of island-arc volcanic rocks. Plagioclase with contrasted zoning styles may coexist within a single lithologic unit or even within a single thin section. Especially notable is the presence of scattered plagioclase phenocrysts with complex zoning throughout Unit 7 in Hole 834B, which in other respects is relatively uniform in composition and appears to have had little or no differential sorting of crystals and liquid. Although our study is by no means comprehensive, it is sufficient to indicate that magmatic conditions have been variable during crystallization of these rocks, and mixing or at least minor contamination may be required to explain some of the relations observed. By analogy with experimental studies, it is possible that variations in water content, either over time or within different parts of a chamber or conduit system, have contributed to the observed contrasts in zoning.

Modelos determinístico y probabilístico para la estimación de la carga de nitratos en una cuenca rural

En este trabajo se desarrolló un modelo probabilístico que utiliza la teoría de la función de densidad de probabilidades derivada para estimar la carga media anual de nitratos transportada por el escurrimiento superficial, utilizando una relación funcional entre el escurrimiento y la carga de nitratos. El modelo determinístico hidrológico y de calidad de agua denominado Simulator for Water Resources in Rural Basins - Water Quality (SWRRB-WQ) fue utilizado para estimar la carga de nitratos en el escurrimiento superficial. Este modelo emplea como variable de entrada la precipitación diaria observada en la Estación del Aeropuerto de Olavarría durante el período 1988 a 2002. Para la calibración del modelo se aplicó una nueva metodología que estima la incertidumbre en los valores observados. Ambos modelos probabilístico y determinístico se aplican en una subcuenca rural del arroyo Tapalqué (provincia de Buenos Aires, Argentina) y finalmente se comparan los valores de la carga de nitratos estimados con los dos modelos con las observaciones realizadas en la sección del arroyo motivo de este estudio. Los resultados muestran que la carga media de nitratos obtenida con el modelo probabilístico es del mismo orden de magnitud que los valores medios observados y estimados con el modelo hidrológico y de calidad de agua SWRRB-WQ.

Chemical and isotopic compositions of rocks and minerals from the Palenyi Island, Por'ya Guba (Bay), White Sea

Hypersthene-garnet-sillimanite-quartz enclaves were studied in orthopyroxene-plagioclase and orthopyroxene-clinopyroxene crystalline schists and gneisses from shear zones exposed in the Palenyi Island within the Early Proterozoic Belomorian Mobile Belt. Qualitative analysis of mineral assemblages indicates that these rocks were metamorphosed to the granulite facies (approximately 900°C and 10-11 kbar). Oxygen isotopic composition was determined in rock-forming minerals composing zones of the enclaves of various mineral and chemical composition. Closure temperatures of the isotopic systems obtained by methods of oxygen isotopic thermometry are close to values obtained with mineralogical geothermometers (garnet-orthopyroxene and garnet-biotite) and correspond to the high-temperature granulite facies (860-900°C). Identified systematic variations in d18O values were determined in the same minerals from zones of different mineral composition. Inasmuch as these zones are practically in contact with one another, these variations in d18O cannot be explained by primary isotopic heterogeneity of the protolith. Model calculations of the extent and trend of d18O variations in minerals suggest that fluid-rock interaction at various integral fluid/rock ratios in discrete zones was the only mechanism that could generate the zoning. This demonstrates that focused fluid flux could occur in lower crustal shear zones. Preservation of high-temperature isotopic equilibria of minerals testifies that the episode of fluid activity at the peak of metamorphism was very brief.

La planificación estática-la planificación dinámica : Ausencia de planes de ordenamiento territorial municipal

Mucho ofthe towns of Mendoza have been working for years with a methodology built with traditional zoningand code of permitted uses,not permitted or conditional. With these instrument sexpectthe presentation of private enter prisesto assess whether it complies with these regulationsto authorize the works.These agencies have a plan with zoning and code application shave already considered planning. This form of work, shows clearly the lack of actions to drive urban developmentsin the department, initiatives on the issue only limited to astatic situation, waiting for proposal sand external actions,not being able to see the advantagesand /or contribution saccom panying the Land Use Plan. Une of the important elements to considerin the Plan process, is the incorporation of participatory stage allows, consensus and guidanceto policy makers, community in territorial actions. For this way are designed and constructed public works, to address concerns of the population and in some cases,works that will produce community supportat election time. A look at the performance of Cities hall suchas Granada City Council, Churriana de la Vega and Jun, you can observe that the planning can be done other wise, as articulated action from the same organism. In principle determining zoning and uses of spaceis integral to the Land Use Planand that it further comprises the development proposals,the lines of action and prioritization of programs and projects. These local governants, which manage a municipality, working withdy namic planning councilasit implements the proposed urban development, agricultural, commercial and industrialin its territory and build public work saccording to plan. Since 2009,the province has a Law of Zoningand Land Use demanded Municipal Land Management Plans, but three years after the enactmentof the 18 only has aplan.Thisis due to two reasons:the policy makersdo not understand the multiplicity of elements and facets of a plan covering the other,the plans are perceived as a limitation on their actions , a fact not willing to accept. The dissemination of know ledge and the, new ways toaddress the Land Use Planning and management of conflicts generated by the unprecedented growthwith incompatible usesin these cities that the component swhich will requirel and manager stoimplement aplanning Plans. Tusa dinámica risión Fromm te municipalitos in thais contexto de can tal abur innovación and a newway of governing

Disputa de Proyectos en Ecuador : El Hecho Social del 30 de Septiembre de 2010

El hecho social estudiado en este trabajo es lo ocurrido el 30 de Septiembre del año 2010 en Ecuador, cuando un sector de las fuerzas armadas y de la policía realizan una protesta en contra de la Ley de Servicio Público. Esta protesta fue acompañada, entre otras, por un conjunto de acciones que incluyeron la retención del presidente Rafael Correa por más de 10 horas en el hospital policial, distintos hechos delictivos en varios puntos del país, la toma del Aeropuerto de Quito, el intento de tomar los medios de comunicación públicos. Ante esto, se produjo una importante y rápida repercusión a nivel internacional y especialmente desde Latinoamérica. A lo largo del trabajo, se analizará cómo intervienen y se posicionan ante el hecho distintos actores nacionales e internacionales, políticos, sociales, culturales y económicos, lo cual permitirá reconstruir los intereses en juego, la disputa de proyectos y los conflictos de intereses latentes no sólo en Ecuador, sino en toda la región Latinoamérica. El análisis que se realiza en este trabajo se hace a partir de la construcción de una base de datos de medios gráficos argentinos (Clarín, La Nación, Página 12, Perfil), ecuatorianos (Diario Hoy, Diario Popular, El Universo, El Telégrafo) y latinoamericanos como Telesur y con un marco teórico desarrollado a partir de la bibliografía. Desde los Medios Masivos de Comunicación, así como distintos actores, fueron considerando lo ocurrido como una sublevación policial, un intento de golpe de estado o un autogolpe. Esto es lo que se reconstruirá a lo largo del trabajo

Disputa de Proyectos en Ecuador : El Hecho Social del 30 de Septiembre de 2010

El hecho social estudiado en este trabajo es lo ocurrido el 30 de Septiembre del año 2010 en Ecuador, cuando un sector de las fuerzas armadas y de la policía realizan una protesta en contra de la Ley de Servicio Público. Esta protesta fue acompañada, entre otras, por un conjunto de acciones que incluyeron la retención del presidente Rafael Correa por más de 10 horas en el hospital policial, distintos hechos delictivos en varios puntos del país, la toma del Aeropuerto de Quito, el intento de tomar los medios de comunicación públicos. Ante esto, se produjo una importante y rápida repercusión a nivel internacional y especialmente desde Latinoamérica. A lo largo del trabajo, se analizará cómo intervienen y se posicionan ante el hecho distintos actores nacionales e internacionales, políticos, sociales, culturales y económicos, lo cual permitirá reconstruir los intereses en juego, la disputa de proyectos y los conflictos de intereses latentes no sólo en Ecuador, sino en toda la región Latinoamérica. El análisis que se realiza en este trabajo se hace a partir de la construcción de una base de datos de medios gráficos argentinos (Clarín, La Nación, Página 12, Perfil), ecuatorianos (Diario Hoy, Diario Popular, El Universo, El Telégrafo) y latinoamericanos como Telesur y con un marco teórico desarrollado a partir de la bibliografía. Desde los Medios Masivos de Comunicación, así como distintos actores, fueron considerando lo ocurrido como una sublevación policial, un intento de golpe de estado o un autogolpe. Esto es lo que se reconstruirá a lo largo del trabajo

Mineral composition and major element oxides of gabbros from ODP Hole 179-1105A, southwest Indian Ridge

Hole 1105A penetrated 158 m of gabbros at a site offset 1.3 km east-northeast from Hole 735B on the Atlantis Bank near the Atlantis II Fracture Zone. A total of 118 m of dominantly medium- to coarse-grained intercalated Fe-Ti oxide gabbro and olivine gabbro was recovered from Hole 1105A that shows many petrographic features similar to those recovered from the upper part of Hole 735B. The main rock types are distinguished based on the constituent cumulus phases, with the most primitive gabbros consisting of olivine, plagioclase, and clinopyroxene. The inferred crystallization order is subsequently Fe-Ti oxides (ilmenite and titanomagnetite), followed by orthopyroxene, then apatite, and finally biotite. Orthopyroxene appears to replace olivine in a narrow middle interval. The magmatic evolution is likewise reflected in the mineral compositions. Plagioclase varies from An66 to An28. Olivine varies from Fo78 to Fo35. The gap in olivine crystallization occurs between Fo46 and Fo40 and coincides approximately with the appearance of orthopyroxene (~En50). The clinopyroxenes show large compositional variation in Mg/(Mg + Fe total) from 0.84 to 0.51. The nonquadrilateral cations of clinopyroxene similarly show large variations with Ti increasing for the olivine gabbros and decreasing for the Fe-Ti oxide gabbros with the decrease in Mg/(Mg + Fe total). The apatites are mainly flourapatites. The compositional variation in the gabbros is interpreted as a comagmatic suite resulting from fractional crystallization. Pyroxene geothermometry suggests equilibration temperatures from 1100°C and below. The coexisting Fe-Ti oxide minerals indicate subsolidus equilibration temperatures from 900°C for olivine gabbros to 700°C for the most evolved apatite-bearing gabbros. The cryptic variation in the olivine gabbros defines two or three lenses, 40 to 60 m thick, each characterized by a distinct convex zoning with a lower segment indicating upward reverse fractionation, a central maximum, and an upper segment showing normal fractionation. The Fe-Ti oxide gabbros show cryptic variations independent of the host olivine gabbros and reveal a systematic upward normal fractionation trend transgressing host olivine gabbro boundaries. Forward fractional crystallization modeling, using a likely parental magma composition from the Atlantis II Fracture Zone (MgO = 7.2 wt%; Mg/[Mg + Fe2+] = 0.62), closely matches the compositions of coexisting olivine, plagioclase, and clinopyroxene. This modeling suggests cosaturation of olivine, plagioclase, and clinopyroxene from 1155°C and the addition of Fe-Ti oxides from 1100°C. The liquid line of descent initially shows increasing FeO with moderately increasing SiO2. After saturation of Fe-Ti oxides, the liquid strongly decreases in FeO and TiO2 and increases in SiO2, reaching dacitic compositions at ~10% liquid remaining. The calculations indicate that formation of olivine gabbros can be accounted for by <65% fractionation and that only the residual 35% liquid was saturated in Fe-Ti oxides. The modeling of the solid fractionation products shows that both the olivine gabbro and the Fe-Ti oxide gabbros contain very small amounts of trapped liquid (<5%). The implications are that the gabbros represent crystal mush that originated in a recharging and tapping subaxial chamber. Compaction and upward melt migration in the crystal mush appear to have been terminated with relatively large amounts of interstitial liquid remaining in the upper parts of the cumulate mush. This termination may have been caused by tectonic disturbances, uplift, and associated withdrawal of magma into the subaxial dike and sill system. Prolonged compaction and cooling of the trapped melt in the mush formed small differentiated bodies and lenses by pressure release migration and crystallization along syntectonic channels. This resulted in differentiation products along lateral and vertical channelways in the host gabbro that vary from olivine gabbro, to Fe-Ti oxide gabbro, gabbronorite, and apatite gabbros and show large compositional variations independent of the host olivine gabbros.

La planificación estática-la planificación dinámica : Ausencia de planes de ordenamiento territorial municipal

Mucho ofthe towns of Mendoza have been working for years with a methodology built with traditional zoningand code of permitted uses,not permitted or conditional. With these instrument sexpectthe presentation of private enter prisesto assess whether it complies with these regulationsto authorize the works.These agencies have a plan with zoning and code application shave already considered planning. This form of work, shows clearly the lack of actions to drive urban developmentsin the department, initiatives on the issue only limited to astatic situation, waiting for proposal sand external actions,not being able to see the advantagesand /or contribution saccom panying the Land Use Plan. Une of the important elements to considerin the Plan process, is the incorporation of participatory stage allows, consensus and guidanceto policy makers, community in territorial actions. For this way are designed and constructed public works, to address concerns of the population and in some cases,works that will produce community supportat election time. A look at the performance of Cities hall suchas Granada City Council, Churriana de la Vega and Jun, you can observe that the planning can be done other wise, as articulated action from the same organism. In principle determining zoning and uses of spaceis integral to the Land Use Planand that it further comprises the development proposals,the lines of action and prioritization of programs and projects. These local governants, which manage a municipality, working withdy namic planning councilasit implements the proposed urban development, agricultural, commercial and industrialin its territory and build public work saccording to plan. Since 2009,the province has a Law of Zoningand Land Use demanded Municipal Land Management Plans, but three years after the enactmentof the 18 only has aplan.Thisis due to two reasons:the policy makersdo not understand the multiplicity of elements and facets of a plan covering the other,the plans are perceived as a limitation on their actions , a fact not willing to accept. The dissemination of know ledge and the, new ways toaddress the Land Use Planning and management of conflicts generated by the unprecedented growthwith incompatible usesin these cities that the component swhich will requirel and manager stoimplement aplanning Plans. Tusa dinámica risión Fromm te municipalitos in thais contexto de can tal abur innovación and a newway of governing

La planificación estática-la planificación dinámica : Ausencia de planes de ordenamiento territorial municipal

Mucho ofthe towns of Mendoza have been working for years with a methodology built with traditional zoningand code of permitted uses,not permitted or conditional. With these instrument sexpectthe presentation of private enter prisesto assess whether it complies with these regulationsto authorize the works.These agencies have a plan with zoning and code application shave already considered planning. This form of work, shows clearly the lack of actions to drive urban developmentsin the department, initiatives on the issue only limited to astatic situation, waiting for proposal sand external actions,not being able to see the advantagesand /or contribution saccom panying the Land Use Plan. Une of the important elements to considerin the Plan process, is the incorporation of participatory stage allows, consensus and guidanceto policy makers, community in territorial actions. For this way are designed and constructed public works, to address concerns of the population and in some cases,works that will produce community supportat election time. A look at the performance of Cities hall suchas Granada City Council, Churriana de la Vega and Jun, you can observe that the planning can be done other wise, as articulated action from the same organism. In principle determining zoning and uses of spaceis integral to the Land Use Planand that it further comprises the development proposals,the lines of action and prioritization of programs and projects. These local governants, which manage a municipality, working withdy namic planning councilasit implements the proposed urban development, agricultural, commercial and industrialin its territory and build public work saccording to plan. Since 2009,the province has a Law of Zoningand Land Use demanded Municipal Land Management Plans, but three years after the enactmentof the 18 only has aplan.Thisis due to two reasons:the policy makersdo not understand the multiplicity of elements and facets of a plan covering the other,the plans are perceived as a limitation on their actions , a fact not willing to accept. The dissemination of know ledge and the, new ways toaddress the Land Use Planning and management of conflicts generated by the unprecedented growthwith incompatible usesin these cities that the component swhich will requirel and manager stoimplement aplanning Plans. Tusa dinámica risión Fromm te municipalitos in thais contexto de can tal abur innovación and a newway of governing

Disputa de Proyectos en Ecuador : El Hecho Social del 30 de Septiembre de 2010

El hecho social estudiado en este trabajo es lo ocurrido el 30 de Septiembre del año 2010 en Ecuador, cuando un sector de las fuerzas armadas y de la policía realizan una protesta en contra de la Ley de Servicio Público. Esta protesta fue acompañada, entre otras, por un conjunto de acciones que incluyeron la retención del presidente Rafael Correa por más de 10 horas en el hospital policial, distintos hechos delictivos en varios puntos del país, la toma del Aeropuerto de Quito, el intento de tomar los medios de comunicación públicos. Ante esto, se produjo una importante y rápida repercusión a nivel internacional y especialmente desde Latinoamérica. A lo largo del trabajo, se analizará cómo intervienen y se posicionan ante el hecho distintos actores nacionales e internacionales, políticos, sociales, culturales y económicos, lo cual permitirá reconstruir los intereses en juego, la disputa de proyectos y los conflictos de intereses latentes no sólo en Ecuador, sino en toda la región Latinoamérica. El análisis que se realiza en este trabajo se hace a partir de la construcción de una base de datos de medios gráficos argentinos (Clarín, La Nación, Página 12, Perfil), ecuatorianos (Diario Hoy, Diario Popular, El Universo, El Telégrafo) y latinoamericanos como Telesur y con un marco teórico desarrollado a partir de la bibliografía. Desde los Medios Masivos de Comunicación, así como distintos actores, fueron considerando lo ocurrido como una sublevación policial, un intento de golpe de estado o un autogolpe. Esto es lo que se reconstruirá a lo largo del trabajo