Main Conduit Research Articles

Geological and geophysical methods relevant to decipher the structure and emplacement of granites: Insights from the Calmayo pluton (Eastern Sierras Pampeanas, Argentina)

In this paper, the evolution of the fabric and 3D geometry of the Calmayo trondhjemitic pluton (512.1 ± 3.4 Ma; Sierra Chica, Córdoba, Argentina) is analyzed using Anisotropy of Magnetic Susceptibility (AMS) measurements combined with structural and microstructural data. Gravity data reveal that the pluton is a funnel-shaped body resting on one main root zone detected below the central portion of the pluton. The microstructural observations in the trondhjemite rocks show a progressive textural overprint from magmatic, through high-T to low-T solid-state deformation textures. This overprint is interpreted to be a consequence of the dynamic emplacement and local deformation, particularly close to the adjacent Soconcho shear zone. Late oxidation of the magnetic mineral assemblage (martitization of magnetite) is more intense in the central and southern sectors close to the root zone, explaining the flat magnetic response of this area, and contrasting with a noisy domain to the northeast where magnetite is preserved. We propose that the Calmayo pluton was constructed by several pulses that ascended through a root zone or main conduit. This root zone represents feeder dykes that exploited tension fractures linked to the Soconcho shear zone. Fluids responsible for the late oxidation would have followed similar paths through this protracted shear zone.

Initiation and evolution of knickpoints and their role in cut-and-fill processes in active submarine channels

Abstract Submarine channels are the main conduits and intermediate stores for sediment transport into the deep sea, including organics, pollutants, and microplastics. Key drivers of morphological change in channels are upstream-migrating knickpoints whose initiation has typically been linked to episodic processes such as avulsion, bend cutoff, and tectonics. The initiation of knickpoints in submarine channels has never been described, and questions remain about their evolution. Sedimentary and flow processes enabling the maintenance of such features in non-lithified substrates are also poorly documented. Repeated high-resolution multibeam bathymetry between 2012 and 2018 in the Capbreton submarine canyon (southeastern Bay of Biscay, offshore France) demonstrates that knickpoints can initiate autogenically at meander bends over annual to multi-annual time scales. Partial channel clogging at tight bends is shown to predate the development of new knickpoints. We describe this initiation process and show a detailed morphological evolution of knickpoints over time. The gradients of knickpoint headwalls are sustained and can grow over time as they migrate through headward erosion. This morphology, associated plunge pools, and/or development of enhanced downstream erosion are linked herein to the formation and maintenance of hydraulic jumps. These insights of autogenically driven, temporally high-frequency knickpoints reveal that cut-and-fill cycles with depths of multiple meters can be the norm in submarine systems.

An integrated hydrogeological approach to evaluate the leakage potential from a complex and fractured karst aquifer, example of Abolabbas Dam (Iran)

The design and construction of dams are risky in karst regions with active tectonic settings and strong heterogeneity due to their leakage potential. Hydrogeological characterization by karst-specific methods can be used to reduce the risk of improper dam construction. Numerous karstic dams have been constructed in the world in simple tectonic settings. In this study, a combination of geological and hydrogeological investigations is used with extensive data collection to evaluate the leakage potential of the Abolabbas Dam construction project at the Malagha karst aquifer, a tectonized highland karst region in the southwest of Iran. Two thrust faults which bounded the Malagha karst aquifer (overthrusting) caused extensive crushed zones, continuous lengths with high permeabilities in most of the boreholes, extensive open joints, and small-size solution cavities. The results of artificial tracer tests imply that the flow regime is diffuse. The flat water table, diffuse flow regime, extensive crushed zones, and continuous high-permeabilities most probably imply that the groundwater flows through an extensive network of joints without main conduits to drain the system. Despite a diffuse flow regime, an extensive grout curtain both in length and depth is required to prevent leakage because the loose materials of the crushed zones will be washed out without it under high hydraulic gradients after dam impoundment. The impermeable formation is too deep due to overthrusting. Therefore, a huge leakage may occur under the hanging grout curtain. The results allow a clearer understanding of the location and properties of fracture zones, erodible materials, high permeability zones, groundwater flow regime, and zones of preferential flow which are essential for reducing the failure of dam construction in such environments. Overall, it is demonstrated that integrating different complementary methods can help to minimize the uncertainties inherent in engineering problems in similar karst scarce-data regions.

Observed Variability of the North Atlantic Current in the Rockall Trough From 4 Years of Mooring Measurements

AbstractThe Rockall Trough is one of the main conduits for warm Atlantic Water to the Nordic Seas. Ocean heat anomalies, originating from the eastern subpolar gyre, are known to influence Arctic sea ice extent, marine ecosystems, and continental climate. Knowledge of the transport through this basin has previously been limited to estimates from hydrographic sections which cannot characterize the intra‐annual and multiannual variability. As part of the Overturning in the Subpolar North Atlantic Programme (OSNAP), a mooring array was deployed in the Rockall Trough in order to obtain the first continuous measurements of transport. Here, we define the methodology and the errors associated with estimating these transports. Results show a 4‐year mean northward transport of 6.6 Sv (1 Sv = 106 m3/s) by the North Atlantic Current (NAC) in the east and interior of the Rockall Trough (2014–2018). A mean transport of −2.0 Sv (southward) is observed in the west of the basin, which could be part of a recirculation around the Rockall Plateau. The 90‐day low‐pass‐filtered transport shows large subannual and interannual variability (−1.6 to 9.1 Sv), mostly resulting from changes in the midbasin geostrophic transport. Satellite altimetry reveals the periods of low and high transport are associated with significant changes in the Rockall Trough circulation. There is a detectable seasonal signal, with the greatest transport in spring and autumn.

Lateral variations in the Unit 7\u20138 boundary zone of the Rum Eastern Layered Intrusion, NW Scotland: implications for the origin and timing of Cr-spinel seam formation

The Rum Layered Suite, NW Scotland, hosts Cr-spinel seams at the bases of peridotite–troctolite macro-rhythmic units in the eastern portion of the intrusion. Here, we present detailed field observations together with microstructural and mineral chemical analyses for the Unit 7–8 Cr-spinel seam and associated cumulates in the Eastern Layered Intrusion. Detailed mapping and sampling reveal significant lateral variations in the structural characteristics and mineral compositions of the Unit 7–8 boundary zone rocks. Although the Cr-spinel seam is laterally continuous over ~ 3 km, it is absent towards the centre and the margins of the intrusion. The compositional characteristics of Cr-spinel and plagioclase vary systematically along strike, exhibiting a chemical evolution towards more differentiated compositions with increasing distance from the main feeder conduit of the Rum intrusion; the Long Loch Fault. On the basis of our combined datasets, we propose that the upper part of the troctolite, the anorthosite layer underlying the Cr-spinel seam and the seam itself formed during a multi-stage magma replenishment event. The stages can be summarised as follows: (1) peridotite schlieren and anorthosite autoliths formed following melt infiltration and cumulate assimilation in the crystal mush of the Unit 7 troctolite. (2) The anorthosite layer then formed from the Unit 7 troctolite crystal mush by thermal erosion and dissolution due to infiltrating magma. (3) Subsequent dissolution of the anorthosite layer by new replenishing magma led to peritectic in situ crystallisation of the Unit 7–8 Cr-spinel seam, with (4) continued magma input eventually producing the overlying Unit 8 peridotite. In the central part of the Rum Layered Suite, the aforementioned assimilation of the troctolitic footwall formed the anorthosite layer. However, the absence of anorthosite in close proximity to the Long Loch Fault can be explained by enhanced thermochemical erosion close to the feeder zone, and its absence close to the margins of the intrusion, at maximum distance from the Long Loch Fault, may be due to cooling of the magma and loss of erosion potential. In line with other recent studies on PGE-bearing chromitites in layered intrusions, we highlight the importance of multi-stage intrusive magma replenishment to the formation of spatially coupled anorthosite and Cr-spinel seams, as well as the lateral mineral chemical variations observed in the Unit 7–8 boundary zone cumulates.

The remarkable volcanism of Shastina, a stratocone segment of Mount Shasta, California

Abstract Mount Shasta, a 400 km3 volcano in northern California (United States), is the most voluminous stratocone of the Cascade arc. Most Mount Shasta lavas vented at or near the present summit; relatively smaller volumes erupted from scattered vents on the volcano’s flanks. An apron of pyroclastic and debris flows surrounds it. Shastina, a large and distinct cone on the west side of Mount Shasta, represents a brief but exceptionally vigorous period of eruptive activity. Its volume of ∼13.5 km3 would make Shastina itself one of the larger Holocene Cascade stratovolcanoes. Its andesite-dacite lavas average 63 wt% SiO2 and have little compositional or petrographic variation; they erupted almost entirely from one central vent, although a single vent below Shastina’s north side erupted a flow of the same composition. Eruptions ended with explosive enlargement and breaching of the central crater and successive emplacement of four, more-silicic dacite domes within the crater and pyroclastic flows down its flank. Black Butte, a large volcanic dome and pyroclastic complex below the west flank of Shastina, is petrographically and chemically distinct but only slightly younger than Shastina itself, part of a nearly continuous Shastina–Black Butte eruptive episode. Shastina overlies the widespread pumice of Red Banks, erupted from the Mount Shasta summit area and 14C dated at ca. 10,900 yr B.P. (calibrated). Shastina and Black Butte pyroclastic deposits have calibrated 14C ages indistinguishable from one another at ca. 10,700 cal. yr B.P. A cognate granitic-textured inclusion in a late Shastina lava flow yields a 238U-230Th date on zircons within error of those ages. Our conclusion that the entire, voluminous Shastina–Black Butte episode lasted no more than a few hundred years is confirmed by almost identical remanent magnetic directions of all of the lavas and pyroclastic deposits. Although extremely similar, the remanent magnetic directions do reveal a short path of secular variation through the eruptive sequence. We conclude that the entire Shastina–Black Butte eruptive episode lasted no more than ∼200 yr. The magmas that produced the Shastina and Black Butte eruptions were separate individual bodies at different crustal levels. Each of these eruptive sequences probably represents magma approximating a liquid composition that experienced only minimal differentiation or crustal contamination and remained separated from the main central conduit for most eruptions of Mount Shasta. The probability of another rapidly developing, brief but voluminous eruptive episode at Mount Shasta is low but should not be ignored in evaluating future possible eruptive hazards.

Imaging the Salinelle Mud Volcanoes (Sicily, Italy) using integrated geophysical and geochemical surveys

Geochemical and geophysical prospecting methods (including measurements of soil heat flux and soil CO2 flux, gravimetry, self-potential and geomagnetism) are used to produce an integrated data set aimed at imaging the migration of fluids in the sub-surface at the Salinelle mud volcanoes, located on the lower southwestern flank of Mt Etna (Sicily, Italy). This area was affected by magmatic eruptions from local volcanic centers between about 48 and 27 ka. Today, only pseudo-volcanic phenomena due to over-pressured multiphase pore fluids there occur. Carbon dioxide of magmatic origin, mixed with biogenic hydrocarbons, warm hypersaline waters and mud, are constantly released at the surface through the main conduits of mud volcanoes, whose activity is characterized by alternation of mild gas bubbling periods and strong paroxysmal phases. The latter produce violent gas eruptions that eject warm water (T ≈ 50° C) to a height up to about 1 m. Surface distribution of the geophysical and geochemical parameters have been investigated to detect the main pathways through which fluids move toward the shallow crust. Integration of geochemical, geophysical and geological maps allowed for the tracing of the fluid flow in the shallowest (a few tens of meters below the surface) part of the local hydrothermal system. Our results showed that the rising of fluids from a deep reservoir is controlled by the main structural and geological features of the area and their temporal and spatial evolution depends on pressure conditions inside the hydrothermal system.

Permeability evolution of grout infilled fractures subjected to triaxial compression with low confining pressure

Fractures in rock masses not only are main flow conduit for groundwater, but also provide planes of weakness on which further displacement can more readily occur. Grouting has been widely used to reduce the permeability of fractured rocks, as well as to improve the stability of fractured rocks. Therefore, fractures infilled with grout appear extensively in practice, and may be subjected to different in-situ stress conditions during the construction and operation life of tunnels and underground spaces in fractured rock masses. To examine the stress induced changes in permeability of grout infilled fractures, we performed triaxial compression tests on fractured granite samples infilled with grout, during which continuous permeability measurements were also conducted. Both planar and rough fractures with different apertures were tested. The permeability of infilled fractures slightly decreased with increasing deviatoric stress from 0 to the crack damage stress, followed by drastic enhancement in permeability with further increasing deviatoric stress. The fracture permeability increased by about 5–10 times at the peak deviatoric stress compared with that at the deviatoric stress of 5 MPa. Both CT techniques and particle discrete element models were used to investigate the changes in the microstructures of grouts and granites, as well as the interface between them. The results show that compression induced cracks in grouts and grout-granite interfaces are the main sources for the enhancements in permeability of grout infilled fractures under triaxial compression with low confining pressures.

Past ice sheet–seabed interactions in the northeastern Weddell Sea embayment, Antarctica

Abstract. The Antarctic ice sheet extent in the Weddell Sea embayment (WSE) during the Last Glacial Maximum (LGM; ca. 19–25 calibrated kiloyears before present, ka cal BP) and its subsequent retreat from the shelf are poorly constrained, with two conflicting scenarios being discussed. Today, the modern Brunt Ice Shelf, the last remaining ice shelf in the northeastern WSE, is only pinned at a single location and recent crevasse development may lead to its rapid disintegration in the near future. We investigated the seafloor morphology on the northeastern WSE shelf and discuss its implications, in combination with marine geological records, to create reconstructions of the past behaviour of this sector of the East Antarctic Ice Sheet (EAIS), including ice–seafloor interactions. Our data show that an ice stream flowed through Stancomb-Wills Trough and acted as the main conduit for EAIS drainage during the LGM in this sector. Post-LGM ice stream retreat occurred stepwise, with at least three documented grounding-line still-stands, and the trough had become free of grounded ice by ∼10.5 ka cal BP. In contrast, slow-flowing ice once covered the shelf in Brunt Basin and extended westwards toward McDonald Bank. During a later time period, only floating ice was present within Brunt Basin, but large “ice slabs” enclosed within the ice shelf occasionally ran aground at the eastern side of McDonald Bank, forming 10 unusual ramp-shaped seabed features. These ramps are the result of temporary ice shelf grounding events buttressing the ice further upstream. To the west of this area, Halley Trough very likely was free of grounded ice during the LGM, representing a potential refuge for benthic shelf fauna at this time.

Thermal Fluid Changes after Operating a Geothermal System: A Case Study of the Chingshui Geothermal Field, Taiwan

The operation of Taiwan’s first geothermal power plant from 1981 to 1993 affected the chemistry of hot fluids in the Chingshui geothermal field. Long-term chemical and isotope data from the production wells have been analyzed since 1973, and the rising steam ratio and enthalpy indicate that shortages of recharging fluids lead to a serious boiling and scaling of carbonates within the first few years of production. Furthermore, the progressively depleted hydrogen and oxygen isotope ratios and the high chloride concentrations in the southern part of the reservoir after discharge indicate that the hot fluids may have been derived from high altitudes and circulated through a deep layer during the discharge period. Decreasing chloride concentrations, lowered silica temperatures, and enriched hydrogen isotope values in the northern part of the reservoir indicate that there is a shallower meteoric fluid circulation from another fractured system that has seeped into and discharged the reservoir when the pressure of the main conduit dropped. After a long non-discharging period, the isotope values are enriched, the concentration of chloride is halved, and silica temperatures are lower than initially state. These observations indicate that the reservoir after the pressure drop was recharged by a shallower meteoric fluid, but the residence time is too short for heating to the initial condition.

Application of Geophysical and Hydrogeochemical Methods to the Protection of Drinking Groundwater in Karst Regions.

To provide theoretical support for the protection of centralized drinking groundwater sources in karst areas, it is necessary to accurately identify the development of karst conduits and analyze the differences in hydrogeochemical characteristics of different karst systems. This provides a scientific basis for the accurate designation of risk zones that may cause drinking groundwater pollution. In this study, a geophysical survey, hydrogeological chemical process analysis and optimized fuzzy cluster analysis were used to gradually improve the understanding of karst water systems. AMT and HDR methods were used to calibrate the resistivity around the water-filling karst conduits, which ranged from 39 to 100 Ω·m. A total of seven karst systems were identified, including four karst systems in the north of the study area, one karst system in the west and two karst systems in the south. Analysis of the hydrochemical data showed that HCO3-Ca and HCO3-Mg-Ca types accounted for 90% of all samples. The δD and δ18O values of their main conduits were −51.70‰ to −38.30‰ and −7.99‰ to −5.96‰, respectively. The optimized fuzzy clustering analysis method based on the weight of variables assigned by AHP more accurately verified karst water systems. Based on these findings, the drinking groundwater source risk zone was designated with an area of 33.90 km2, accounting for 34.5% of the study area. This study effectively improved the rationality and accuracy of the designation of drinking groundwater source risk zones in karst areas, and provided a scientific basis for the identification of karst water systems and decision-making of drinking groundwater source protection in karst areas.

Karstic conduits and watershed identification based on the morphological characteristics of depressions in the Yunnan–Guizhou Plateau of China

In the investigation of karstic form and underground karst water, determination of the location and geometric properties of karstic conduits and underground watersheds is one of the greatest problems not yet adequately resolved. In the karst terrain of the Yunnan–Guizhou Plateau of China, karst depressions are a product of the formation and evolution of the groundwater system, and the distribution of these depressions is a direct result of crustal uplift and the development of karstic conduits. This terrain is characterized by differences in morphological characteristics of depressions between the region of recharge and the region of outflow/discharge: the region of recharge is marked extensively by circular and random depressions, and is characterized by depressions with higher bottom elevations (referred to here as ‘higher depressions’). Conversely, the region of outflow and discharge is marked extensively by depressions that form long strips or irregular alignments that are distributed along with the karstic conduits, and is characterized by depressions with lower bottom elevations (referred to here as ‘lower depressions’). Here, a methodology has been put forward to determine the possible location and principal directions of karstic conduits and underground hydrogeological watersheds based on surface morphological features of depressions in the region of the Yunnan–Guizhou Plateau, China. The methodology assumes that the contour map that results from determining the bottom elevations of karstic depressions is sufficient to determine the positions of underground hydrogeological divisions and karstic channels. Taking the two main conduits systems in Guizhou Province as an example, a digital elevation model (DEM) was derived from 1:10,000 scale topographic maps with ArcGIS 10.2 and the bottom elevations of depressions were marked. Then a contour map of the bottom elevations of the depressions was produced. The directions of conduits and underground watersheds in the research area were identified from the valleys and ridges of the contour lines. The methodology introduced in this paper offers a new means of determining the location and geometric properties of karstic conduits and extracting the spatial distribution of water systems in the region of the Yunnan–Guizhou Plateau, China. This methodology will be appropriate for investigating karstic areas with continuous crustal uplift and significant variation in the bottom elevation of depressions between the region of recharge and region of discharge.

Colloid transport through soil and other porous media under transient flow conditions—A review

AbstractUnderstanding colloid transport in porous media under transient‐flow conditions is crucial in understanding contaminant transport in soil or the vadose zone where flow conditions vary constantly. In this article, we provide a review of experimental studies, numerical approaches, and new technologies available to determine the transport of colloids in transient flow. Experiments indicate that soil structure and preferential flow are primary factors. In undisturbed soils with preferential flow pathways, macropores serve as main conduits for colloid transport. In homogeneously packed soil, the soil matrix often serves as filter. At the macroscale, transient flow facilitates colloid transport by frequently disturbing the force balance that retains colloids in the soil as indicated by the offset between colloid breakthrough peaks and discharge peaks. At the pore‐scale and under saturated condition, straining, and attachment at solid–water interfaces are the main mechanisms for colloid retention. Variably saturated conditions add more complexity, such as immobile water zones, film straining, attachment to air–water interfaces, and air–water–solid contact lines. Filter ripening, size exclusion, ionic strength, and hydrophobicity are identified as the most influential factors. Our review indicates that microscale and continuum‐scale models for colloid transport under transient‐flow conditions are rare, compared to the numerous steady‐state models. The few transient flow models that do exist are highly parameterized and suffer from a lack of a priori information of required pore‐scale parameters. However, new techniques are becoming available to measure colloid transport in real‐time and in a nondestructive way that might help to better understand transient flow colloid transport.This article is categorized under: Science of Water > Hydrological Processes Science of Water > Water Quality

Fragmentation and Cooperation in the Jihadi International (Sub)System: ‘Islamic State’ vs. Al-Qaeda and Beyond

The article explores the implications the rise of the ‘Islamic State’ (IS) had on the international order and the salafi-jihadi movement. The main argument is that at the height of its activity (2014–2016) IS was a de facto revolutionary state. In this capacity, IS challenged the international order because contrary to revolutionary states in the past it negated the foundations of the Westphalian system. At the same time, the rise of IS had a tremendous impact on the jihadi (sub)system, as it initiated a period of fragmentation and alliance-building. The competition between IS and al-Qaeda for the hegemony of the movement did not revolve around direct fighting as much as efforts to outbid the rival group. One of the main conduits of this competition was the ‘war of bay’as (pledges of allegiance)’, which consisted of competitive oaths of allegiance from local jihadi forces to one of the two groups. In local contexts, the ‘war of bay’as’ increased tensions and factionalism within jihadi groups, as splinter groups decided to side with the new revolutionary foco. The fragmentation of local jihadi groups unfolded along pre-existing cleavages, grievances and resource-related motivations, increasing the levels of violence and complexity in these local conflicts.

Can Karst Conduit Models Be Calibrated? A Dual Approach Using Dye Tracing and Temperature.

Modeling flow and transport using both temperature and dye tracing provides constraints that can improve understanding of karst networks. A laminar flow and transport model using the finite element subsurface flow model simulated the conduit connection between a sinking stream and spring in central Pennsylvania to evaluate how conduit morphology might affect dye transport. Single and overly tortuous conduit models resulted in high concentrations as dye flowed back into the conduit from the matrix after dye injections ceased. A forked conduit model diverted flow from the main conduit, reducing falling limb dye concentration. Latin hypercube sampling was performed to evaluate the sensitivity of 52 parameter combinations (conduit hydraulic conductivity, conduit cross-sectional area, matrix transmissivity, matrix porosity, and dispersivity) for four conduit geometry scenarios. Sensitivity of arrival time for 50% of the dye indicated no parameter combinations which simulate falling limb dye concentrations for tortuous geometries, confirming the importance of the forked geometry regardless of other parameters. Temperature data from high-resolution loggers were then incorporated into the forked conduit model to reproduce seasonal spring temperature using variable sink inflow. Unlike the dye trace models, the thermal models were sensitive to other model parameters, such as conduit cross-sectional area and matrix transmissivity. These results showed this dual approach (dye and temperature) to karst network modeling is useful for (1) exploring the role of conduit and matrix interaction for contaminant storage, (2) constraining karst conduit geometries, which are often poorly understood, and (3) quantifying the effect of seasonal trends on karst aquifers.

Chieftaincy in Malawi: Reinvention, Re-emergence or Resilience? A Kasungu Case Study

As African states emerged from colonial rule and adopted the trappings of western parliamentary government, many nationalist politicians regarded chieftaincy as an archaic institution, either to be abandoned or reduced to ceremonial. Nevertheless, it has become clear that chiefs endure and not merely as cultural ornaments; indeed, in Malawi and elsewhere, they are still the main conduits for communication between the central state and the grassroots, and they continue to play an important role in development initiatives, local dispute resolution and, since the 1990s, as players in the ‘new democracy’, locally and at the national level. This article contributes to investigations into the nature of chieftaincy from precolonial times to the present, using a Malawian example, to ask how far the tenacity of this institution can be attributed to its reinvention, re-emergence or resilience. It examines chieftaincy in one area of Kasungu district in central Malawi from its establishment in the 18th century through the colonial and post-colonial periods up to the present to explore its nature over time. It concludes that the institution endures through a combination of reinvention, resilience and re-emergence. Chieftaincy survives through invoking tradition and adapting to specific historical circumstances but also by virtue of the personal qualities of officeholders. This case study illustrates the dynamism of chiefly governance.

Composition of Magma and Characteristics of the Hydrothermal System of Newberry Volcano, Oregon, From Magnetotellurics

AbstractWe use 3‐D magnetotellurics to improve our understanding of the structure and magma composition of Newberry Volcano in Oregon, USA. Newberry is a broad shield volcano with a summit caldera and strongly bimodal magmatism. Newberry has long been the subject of geothermal exploration research, but that work has focused on the volcano's west flank, leaving the caldera largely unstudied with geophysical methods until recently. Our modeling shows a relatively resistive magma reservoir of approximately 50 Ωm. Our work builds upon recent seismic models and petrological analysis to interpret Newberry's magma reservoir as a dry rhyolite with 8–11% partial melt, which matches the seismically determined melt fraction. Finding the conditions within the magma reservoir that allow the resistivity and seismic analysis to come to the same melt fraction helps us narrow down the magma temperature and composition. From this we infer a dry rhyolitic magma at 850 °C. We also image a prominent vertical conductive anomaly along the south rim below the vent that produced the most recent eruption. The anomaly extends from magma reservoir depths of 3 km to 1 km below the surface where it disperses into the caldera fill. We interpret this as the main conduit for magmatic fluids to reach Newberry's hydrothermal system. Other features that our model shows include higher conductivity along the caldera rim and a resistive older pluton on the west flank.

Plant Development: How Phloem Patterning Occurs.

The phloem tissue is the main conduit for sugars in plants, and its anatomy has to be tightly controled to ensure its functionality. A new study indicates the involvement of receptor-based intercellular signaling in the coordination of cell fate determination within the phloem tissue.

A thermo-hydromechanical displacement discontinuity method to model fractures in high-pressure, high-temperature environments

Geothermal reservoirs, oil wells, radioactive waste disposals, and deep underground mines deal with high-temperature and high-pressure problems. The thermo-hydromechanical coupling may significantly affect the behavior of the rock mass in these applications. Fractures and joints are the main conduits of thermal and hydraulic transition. The displacement discontinuity method (DDM) is ideally suited to model problems containing fractures. However, the DDM in its original formulation is restricted to elasticity problems. It is formulated in this study to take into account the thermo-hydromechanical effects. A numerical formulation and implementation for the thermo-hydromechanical DDM is derived. The proposed numerical model is validated in three parts. The poroelastic, thermoelastic, and thermo-hydromechanical couplings are each validated by analytical or experimental results. The results showed good agreement between the proposed numerical model and analytical or experimental results over various periods. The validations proved the accuracy and applicability of the proposed thermo-hydromechanical numerical model in a wide range of problems. Furthermore, the thermo-hydromechanical effect on crack opening displacement (COD) is modeled. Numerical simulation showed that the maximum COD due to only thermal effects may be reached after almost a year.

Psychotherapeutic Praxis in India: Incorporation and Application of Indigenous Worldviews


 
 
 This research aims to gain insight into the incorporation of indigenous worldviews on mental health. Unstructured interviews were used on 16 counsellors who practised in Bangalore following the phenomenological paradigm. The interviews were audio- recorded and transcribed following which it underwent the 4 stages in Giorgi’s method. The revelatory themes obtained from this study were that clients viewed counsellors as authority figures, they experienced shame and guilt, lack of social support, ostracism, isolation, faced language barriers, feared diagnosis and medication and so on. The main conduit of religion and culture, the family, is influenced by class, education, rural or urban origin, joint or nuclear setup and so on. Counsellors developed the skills and sensitivity to respond to these demands.