The Experts below are selected from a list of 204 Experts worldwide ranked by ideXlab platform
Jonathan S Price - One of the best experts on this subject based on the ideXlab platform.
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effect of mine dewatering on the peatlands of the james bay lowland the role of marine sediments on mitigating peatland drainage
Hydrological Processes, 2013Co-Authors: Peter Whittington, Jonathan S PriceAbstract:The wetlands of the James Bay Lowland comprise one of largest wetland complexes in the world, in part due to the properties (thickness and hydraulic conductivity) of the marine sediment (MS) that underlay them. Dewatering of an open-pit diamond mine is depressurizing the surrounding Silurian bedrock below the MS. Prior to mining, it was assumed that these MS would largely isolate the overlying peatlands from the depressurized regional bedrock aquifer. To assess this isolation, we instrumented a 1.5 km long transect of wells and piezometers located within the zone of the mine's influence that crossed a sequence of bogs, fens, and bedrock outcrops (Bioherms). Results were differentiated between those areas with no MS (near Bioherms) and those underlain by MS (non-Bioherm) along the transect. Between 2007 and 2010 at near-Bioherm and non-Bioherm locations, average peat water tables declined 71 and 31 cm, and hydraulic head declined 66 and 32 cm, in Bioherm and non-Bioherm locations, respectively. Gradients varied from near zero (−0.001) at the start of dewatering to −0.03 (after 5 years) in non-Bioherm areas and from −0.20 to −0.45 in near-Bioherm areas. These gradients corresponded to fluxes (groundwater recharge) of approximately −0.26 mm/day and −2.1 mm/day, in non- and near-Bioherm areas, respectively. Specific discharge (recharge) determined using the known mine dewatering rate and drawdown cone heads and areas corresponded well with measured recharge determined in the non-Bioherm transect locations. A simple rearrangement of Darcy's Law used to calculate the specific discharge highlighted how the ratio of hydraulic conductivity to the thickness of the MS can be used to assess vulnerable areas. Therefore, given the increasing development in Ontario's Far North, considerable attention must be given to both the thickness and hydraulic conductivity of MS. Copyright © 2013 John Wiley & Sons, Ltd.
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Effect of mine dewatering on peatlands of the James Bay Lowland: the role of Bioherms
Hydrological Processes, 2012Co-Authors: Peter Whittington, Jonathan S PriceAbstract:The James Bay Lowland host one of the largest wetland complexes in the world in part due to the low permeability of marine sediments that suppress groundwater seepage losses. Dewatering of an open-pit diamond mine in the area has depressurized the regional bedrock aquifer. Bioherms, fractured limestone outcroppings formed from ancient coral reefs that protrude to the peatland surface, lack this mantle of low-permeability sediments and provide a direct connection between the peatland (surficial) and the regional (bedrock) aquifers. Well transects and piezometer nests were installed around seven Bioherms in the depressurized zone and one in a non-affected zone (control) to monitor the water table drawdown and change in hydraulic gradients around the Bioherms. Water tables in the affected Bioherms decreased between 2 and 4 m in the first 4 years of dewatering. The drawdown in the Bioherms caused a localized water table drawdown in the peat surrounding the Bioherms that extended to approximately 30 m from the edge of the Bioherm during a dry period. Under wet conditions, drawdown was similar to that at the control site. Hydraulic gradients in the peat (which typically are very small) increased over the field seasons and in a few locations exceeded 1. These gradients represented significant losses to the local, near Bioherm, system as at many of the locations surrounding the Bioherms vertical seepage losses ranged between 1 and 4 mm/day, which are similar to the seasonal average evaporative water loss of ~ 3 mm/day. The Bioherms are acting as efficient drainage nodes; however, their influence is localized to the peat immediately (~
Vincent Rommevaux - One of the best experts on this subject based on the ideXlab platform.
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The role of topography and erosion in the development and architecture of shallow-water coral Bioherms (Tortonian–Messinian, Cabo de Gata, SE Spain)
Palaeogeography Palaeoclimatology Palaeoecology, 2020Co-Authors: Raphaël Bourillot, Emmanuelle Vennin, Christophe Kolodka, Jean-marie Rouchy, Antonio Caruso, Christophe Durlet, Christian Chaix, Vincent RommevauxAbstract:23 pagesInternational audienceDuring the Miocene, Mediterranean shallow-water carbonates were rich in scleractinian corals, which thrive in various depositional settings. A Tortonian–Messinian Bioherm belt developing in a heterozoan-dominated ramp was investigated along a 1.2 km continuous transect located in the Cabo de Gata region. The interval studied displays four depositional environments from mid-to-inner ramp, dominated by swell waves and storm energy, deposited as a single, large-scale depositional sequence during a 3rd to 4th order transgressive–regressive cycle. The Bioherms grew in three phases, and were essentially composed of inplace primary frameworks. Three coral genera were the main framebuilders (Porites, Tarbellastrea and rare Siderastrea), associated with melobesioid and mastophoroid red algae and bryozoans as secondary framebuilders. The corals display five morphotypes, from a fast-growing branched type to slow-growing domal to plate morphologies, with an uncommon form of mesh Porites as the dominant morphotype. Changes in coral morphotype and composition of micro-encrusters communities reveal changes in hydrodynamics, detrital influx and perhaps nutrient levels. Bioherms architecture was driven by sea level, palaeotopography and erosion. The coral framework was affected during its development by erosion surfaces metres to tens of metres deep and hundreds of metres wide. Unexpectedly, these surfaces are better developed on the inner edges of the Bioherms. This could indicate the circulation of strong bottom currents between the volcanic palaeohighs and the synoptic relief created by the buildups. Finally, a major sub-aerial erosional episode associated with increasing detrital influxes, ended Bioherm development, thus allowing the colonization of the dead coral substratum by red algae
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The role of topography and erosion in the development and architecture of shallow-water coral Bioherms (Tortonian–Messinian, Cabo de Gata, SE Spain)
Palaeogeography Palaeoclimatology Palaeoecology, 2009Co-Authors: Raphaël Bourillot, Emmanuelle Vennin, Christophe Kolodka, Jean-marie Rouchy, Antonio Caruso, Christophe Durlet, Christian Chaix, Vincent RommevauxAbstract:Abstract During the Miocene, Mediterranean shallow-water carbonates were rich in scleractinian corals, which thrive in various depositional settings. A Tortonian–Messinian Bioherm belt developing in a heterozoan-dominated ramp was investigated along a 1.2 km continuous transect located in the Cabo de Gata region. The interval studied displays four depositional environments from mid-to-inner ramp, dominated by swell waves and storm energy, deposited as a single, large-scale depositional sequence during a 3rd to 4th order transgressive–regressive cycle. The Bioherms grew in three phases, and were essentially composed of in-place primary frameworks. Three coral genera were the main framebuilders (Porites, Tarbellastrea and rare Siderastrea), associated with melobesioid and mastophoroid red algae and bryozoans as secondary framebuilders. The corals display five morphotypes, from a fast-growing branched type to slow-growing domal to plate morphologies, with an uncommon form of mesh Porites as the dominant morphotype. Changes in coral morphotype and composition of micro-encrusters communities reveal changes in hydrodynamics, detrital influx and perhaps nutrient levels. Bioherms architecture was driven by sea level, palaeotopography and erosion. The coral framework was affected during its development by erosion surfaces metres to tens of metres deep and hundreds of metres wide. Unexpectedly, these surfaces are better developed on the inner edges of the Bioherms. This could indicate the circulation of strong bottom currents between the volcanic palaeohighs and the synoptic relief created by the buildups. Finally, a major sub-aerial erosional episode associated with increasing detrital influxes, ended Bioherm development, thus allowing the colonization of the dead coral substratum by red algae.
Peter Whittington - One of the best experts on this subject based on the ideXlab platform.
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effect of mine dewatering on the peatlands of the james bay lowland the role of marine sediments on mitigating peatland drainage
Hydrological Processes, 2013Co-Authors: Peter Whittington, Jonathan S PriceAbstract:The wetlands of the James Bay Lowland comprise one of largest wetland complexes in the world, in part due to the properties (thickness and hydraulic conductivity) of the marine sediment (MS) that underlay them. Dewatering of an open-pit diamond mine is depressurizing the surrounding Silurian bedrock below the MS. Prior to mining, it was assumed that these MS would largely isolate the overlying peatlands from the depressurized regional bedrock aquifer. To assess this isolation, we instrumented a 1.5 km long transect of wells and piezometers located within the zone of the mine's influence that crossed a sequence of bogs, fens, and bedrock outcrops (Bioherms). Results were differentiated between those areas with no MS (near Bioherms) and those underlain by MS (non-Bioherm) along the transect. Between 2007 and 2010 at near-Bioherm and non-Bioherm locations, average peat water tables declined 71 and 31 cm, and hydraulic head declined 66 and 32 cm, in Bioherm and non-Bioherm locations, respectively. Gradients varied from near zero (−0.001) at the start of dewatering to −0.03 (after 5 years) in non-Bioherm areas and from −0.20 to −0.45 in near-Bioherm areas. These gradients corresponded to fluxes (groundwater recharge) of approximately −0.26 mm/day and −2.1 mm/day, in non- and near-Bioherm areas, respectively. Specific discharge (recharge) determined using the known mine dewatering rate and drawdown cone heads and areas corresponded well with measured recharge determined in the non-Bioherm transect locations. A simple rearrangement of Darcy's Law used to calculate the specific discharge highlighted how the ratio of hydraulic conductivity to the thickness of the MS can be used to assess vulnerable areas. Therefore, given the increasing development in Ontario's Far North, considerable attention must be given to both the thickness and hydraulic conductivity of MS. Copyright © 2013 John Wiley & Sons, Ltd.
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Effect of mine dewatering on peatlands of the James Bay Lowland: the role of Bioherms
Hydrological Processes, 2012Co-Authors: Peter Whittington, Jonathan S PriceAbstract:The James Bay Lowland host one of the largest wetland complexes in the world in part due to the low permeability of marine sediments that suppress groundwater seepage losses. Dewatering of an open-pit diamond mine in the area has depressurized the regional bedrock aquifer. Bioherms, fractured limestone outcroppings formed from ancient coral reefs that protrude to the peatland surface, lack this mantle of low-permeability sediments and provide a direct connection between the peatland (surficial) and the regional (bedrock) aquifers. Well transects and piezometer nests were installed around seven Bioherms in the depressurized zone and one in a non-affected zone (control) to monitor the water table drawdown and change in hydraulic gradients around the Bioherms. Water tables in the affected Bioherms decreased between 2 and 4 m in the first 4 years of dewatering. The drawdown in the Bioherms caused a localized water table drawdown in the peat surrounding the Bioherms that extended to approximately 30 m from the edge of the Bioherm during a dry period. Under wet conditions, drawdown was similar to that at the control site. Hydraulic gradients in the peat (which typically are very small) increased over the field seasons and in a few locations exceeded 1. These gradients represented significant losses to the local, near Bioherm, system as at many of the locations surrounding the Bioherms vertical seepage losses ranged between 1 and 4 mm/day, which are similar to the seasonal average evaporative water loss of ~ 3 mm/day. The Bioherms are acting as efficient drainage nodes; however, their influence is localized to the peat immediately (~
Jean-marie Rouchy - One of the best experts on this subject based on the ideXlab platform.
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The role of topography and erosion in the development and architecture of shallow-water coral Bioherms (Tortonian–Messinian, Cabo de Gata, SE Spain)
Palaeogeography Palaeoclimatology Palaeoecology, 2020Co-Authors: Raphaël Bourillot, Emmanuelle Vennin, Christophe Kolodka, Jean-marie Rouchy, Antonio Caruso, Christophe Durlet, Christian Chaix, Vincent RommevauxAbstract:23 pagesInternational audienceDuring the Miocene, Mediterranean shallow-water carbonates were rich in scleractinian corals, which thrive in various depositional settings. A Tortonian–Messinian Bioherm belt developing in a heterozoan-dominated ramp was investigated along a 1.2 km continuous transect located in the Cabo de Gata region. The interval studied displays four depositional environments from mid-to-inner ramp, dominated by swell waves and storm energy, deposited as a single, large-scale depositional sequence during a 3rd to 4th order transgressive–regressive cycle. The Bioherms grew in three phases, and were essentially composed of inplace primary frameworks. Three coral genera were the main framebuilders (Porites, Tarbellastrea and rare Siderastrea), associated with melobesioid and mastophoroid red algae and bryozoans as secondary framebuilders. The corals display five morphotypes, from a fast-growing branched type to slow-growing domal to plate morphologies, with an uncommon form of mesh Porites as the dominant morphotype. Changes in coral morphotype and composition of micro-encrusters communities reveal changes in hydrodynamics, detrital influx and perhaps nutrient levels. Bioherms architecture was driven by sea level, palaeotopography and erosion. The coral framework was affected during its development by erosion surfaces metres to tens of metres deep and hundreds of metres wide. Unexpectedly, these surfaces are better developed on the inner edges of the Bioherms. This could indicate the circulation of strong bottom currents between the volcanic palaeohighs and the synoptic relief created by the buildups. Finally, a major sub-aerial erosional episode associated with increasing detrital influxes, ended Bioherm development, thus allowing the colonization of the dead coral substratum by red algae
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The role of topography and erosion in the development and architecture of shallow-water coral Bioherms (Tortonian–Messinian, Cabo de Gata, SE Spain)
Palaeogeography Palaeoclimatology Palaeoecology, 2009Co-Authors: Raphaël Bourillot, Emmanuelle Vennin, Christophe Kolodka, Jean-marie Rouchy, Antonio Caruso, Christophe Durlet, Christian Chaix, Vincent RommevauxAbstract:Abstract During the Miocene, Mediterranean shallow-water carbonates were rich in scleractinian corals, which thrive in various depositional settings. A Tortonian–Messinian Bioherm belt developing in a heterozoan-dominated ramp was investigated along a 1.2 km continuous transect located in the Cabo de Gata region. The interval studied displays four depositional environments from mid-to-inner ramp, dominated by swell waves and storm energy, deposited as a single, large-scale depositional sequence during a 3rd to 4th order transgressive–regressive cycle. The Bioherms grew in three phases, and were essentially composed of in-place primary frameworks. Three coral genera were the main framebuilders (Porites, Tarbellastrea and rare Siderastrea), associated with melobesioid and mastophoroid red algae and bryozoans as secondary framebuilders. The corals display five morphotypes, from a fast-growing branched type to slow-growing domal to plate morphologies, with an uncommon form of mesh Porites as the dominant morphotype. Changes in coral morphotype and composition of micro-encrusters communities reveal changes in hydrodynamics, detrital influx and perhaps nutrient levels. Bioherms architecture was driven by sea level, palaeotopography and erosion. The coral framework was affected during its development by erosion surfaces metres to tens of metres deep and hundreds of metres wide. Unexpectedly, these surfaces are better developed on the inner edges of the Bioherms. This could indicate the circulation of strong bottom currents between the volcanic palaeohighs and the synoptic relief created by the buildups. Finally, a major sub-aerial erosional episode associated with increasing detrital influxes, ended Bioherm development, thus allowing the colonization of the dead coral substratum by red algae.
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Extensive carbonate algal Bioherms in upper Pleistocene saline lakes of the central Altiplano of Bolivia
Sedimentology, 1996Co-Authors: Jean-marie Rouchy, Michel Servant, Marc Fournier, Christiane CausseAbstract:During the upper Pleistocene the Central Altiplano of Bolivia was repeatedly flooded by deep and extensive saline lakes in response to climatic fluctuations. Development of carbonate algal Bioherms took place during at least three major periods of lacustrine highstands, discontinuously covering the 300-km-long and 100-km-wide lacustrine slopes and terraces up to an elevation of 100 m above the surface of the modern halite crust of Uyuni. Distribution, size and shape of the Bioherms are diverse due to various factors, e.g. the nature and morphology of the substrate and the hydrodynamic conditions that prevailed during growth. On larger palaeoterraces, the build-ups coalesced to form platform-like carbonate accumulations. Although the morphologies closely resemble those induced by cyanobacteria, they were predominantly constructed by other plant communities, probably dominated by filamentous green algae. Cyanobacterial communities flourished in association with these plants, but they did not contribute significantly to the architecture of the Bioherms; they participated to encrust the plant stems and algal bushes or to form thin laminated layers covering the build-ups. A prominent feature of some Bioherms is their composite structure due to repeated algal growth during successive lacustrine episodes that were separated by subaerial exposures with moderate erosional effects. The build-ups located between 3660 and 3680 m elevation display up to three major parts: (1) a massive inner core formed during an early Minchin highstand, before 40 ka; (2) a large peripheral envelope deposited at about 40 ka (late Minchin) and (3) a thinner outermost crust formed during a late glacial event. Lake level dropped during interlacustrine stages, sometimes leading to desiccation and deposition of salt layers in the deepest parts of the system, i.e. the present-day salar of Uyuni.
Raphaël Bourillot - One of the best experts on this subject based on the ideXlab platform.
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The role of topography and erosion in the development and architecture of shallow-water coral Bioherms (Tortonian–Messinian, Cabo de Gata, SE Spain)
Palaeogeography Palaeoclimatology Palaeoecology, 2020Co-Authors: Raphaël Bourillot, Emmanuelle Vennin, Christophe Kolodka, Jean-marie Rouchy, Antonio Caruso, Christophe Durlet, Christian Chaix, Vincent RommevauxAbstract:23 pagesInternational audienceDuring the Miocene, Mediterranean shallow-water carbonates were rich in scleractinian corals, which thrive in various depositional settings. A Tortonian–Messinian Bioherm belt developing in a heterozoan-dominated ramp was investigated along a 1.2 km continuous transect located in the Cabo de Gata region. The interval studied displays four depositional environments from mid-to-inner ramp, dominated by swell waves and storm energy, deposited as a single, large-scale depositional sequence during a 3rd to 4th order transgressive–regressive cycle. The Bioherms grew in three phases, and were essentially composed of inplace primary frameworks. Three coral genera were the main framebuilders (Porites, Tarbellastrea and rare Siderastrea), associated with melobesioid and mastophoroid red algae and bryozoans as secondary framebuilders. The corals display five morphotypes, from a fast-growing branched type to slow-growing domal to plate morphologies, with an uncommon form of mesh Porites as the dominant morphotype. Changes in coral morphotype and composition of micro-encrusters communities reveal changes in hydrodynamics, detrital influx and perhaps nutrient levels. Bioherms architecture was driven by sea level, palaeotopography and erosion. The coral framework was affected during its development by erosion surfaces metres to tens of metres deep and hundreds of metres wide. Unexpectedly, these surfaces are better developed on the inner edges of the Bioherms. This could indicate the circulation of strong bottom currents between the volcanic palaeohighs and the synoptic relief created by the buildups. Finally, a major sub-aerial erosional episode associated with increasing detrital influxes, ended Bioherm development, thus allowing the colonization of the dead coral substratum by red algae
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The role of topography and erosion in the development and architecture of shallow-water coral Bioherms (Tortonian–Messinian, Cabo de Gata, SE Spain)
Palaeogeography Palaeoclimatology Palaeoecology, 2009Co-Authors: Raphaël Bourillot, Emmanuelle Vennin, Christophe Kolodka, Jean-marie Rouchy, Antonio Caruso, Christophe Durlet, Christian Chaix, Vincent RommevauxAbstract:Abstract During the Miocene, Mediterranean shallow-water carbonates were rich in scleractinian corals, which thrive in various depositional settings. A Tortonian–Messinian Bioherm belt developing in a heterozoan-dominated ramp was investigated along a 1.2 km continuous transect located in the Cabo de Gata region. The interval studied displays four depositional environments from mid-to-inner ramp, dominated by swell waves and storm energy, deposited as a single, large-scale depositional sequence during a 3rd to 4th order transgressive–regressive cycle. The Bioherms grew in three phases, and were essentially composed of in-place primary frameworks. Three coral genera were the main framebuilders (Porites, Tarbellastrea and rare Siderastrea), associated with melobesioid and mastophoroid red algae and bryozoans as secondary framebuilders. The corals display five morphotypes, from a fast-growing branched type to slow-growing domal to plate morphologies, with an uncommon form of mesh Porites as the dominant morphotype. Changes in coral morphotype and composition of micro-encrusters communities reveal changes in hydrodynamics, detrital influx and perhaps nutrient levels. Bioherms architecture was driven by sea level, palaeotopography and erosion. The coral framework was affected during its development by erosion surfaces metres to tens of metres deep and hundreds of metres wide. Unexpectedly, these surfaces are better developed on the inner edges of the Bioherms. This could indicate the circulation of strong bottom currents between the volcanic palaeohighs and the synoptic relief created by the buildups. Finally, a major sub-aerial erosional episode associated with increasing detrital influxes, ended Bioherm development, thus allowing the colonization of the dead coral substratum by red algae.