Richard Esser - Profile on Academia.edu (original) (raw)
Papers by Richard Esser
A Meteoritic Event Layer in Antarctic Ice
Meteoritics, Aug 30, 1995
Where the East Antarctic ice sheet meets the Transantarctic Mountains, old, deep glacial ice is t... more Where the East Antarctic ice sheet meets the Transantarctic Mountains, old, deep glacial ice is tilted upward and exposed.Within this visible cross-section of the ice sheet, layers of dark volcanic tephra serve as stratigraphic markers and datable age horizons [1,2]. Systematic sampling of these layers at a well-known meteorite collection site (the Allan Hills Main icefield) has revealed a band consisting of unusually dark and rounded particles, many of which are spheroidal. This debris layer (BIT- 58) extends parallel to the stratigraphy of the ice established from the tephra bands, and thus apparently marks a single depositional event. Several kg of ice from two sites along this band were subsequently collected and melted, yielding a few grams of sediment for further study. Microscopic examination of sieved samples reveals that roughly 95% of the particles consist of a singular olivine-rich hyaloclastic litholo gy; more that 40% of these are spheroidal. The remaining 5% of the sediment consists of grains derived from local bedrock exposures. Particles range in size from sub-micrometer to over 100 micrometers in diameter, with a strong mode around 85 micrometers suggesting sorting by aeolian processes. However, preservation of delicate particle morphologies such as small parasitic spheres suggests that saltation and/or abrasion was limited. A representative group of particles was mounted in epoxy and sectioned for subsequent electron microprobe analysis. All particles show a mixture of three dominant phases; euhedral and/or skeletal olivine, an Fe-rich glass mesostasis, and abundant Fe-Ni opaques (mostly metals and sulfides). There is a strong correlation between particle shape and the size of olivine grains: angular particles contain larger, more distinct (presumably relict) grains, while the most spheroidal particles are so fine-grained they appear homogenous at this scale. Defocused beam major-element analyses of spheroidal particles show good agreement with bulk H chondrite composition (Table 1). Euhedral olivine grains also correspond to typical H-chondrite composition with Mg-rich cores around 17% Fa zoned to rims of 24% Fa near contact with Fe-rich glass. Opaques include some relatively exotic Ni-rich phases, such as a Ni3S2 / gamma Ni,Fe assemblage. Although direct evidence of an extraterrestrial origin for this debris layer (such as the presence of cosmogenic 10Be and 26Al ) has not yet been obtained, the available data strongly suggest that this sediment originated as meteoritic spallation debris. This debris is distinct from other Antarctic "cosmic dust" collections by virtue of its uniform, recognizable ordinary chondrite composition and the consistent relation shown between grain- size and texture. The BIT-58 layer probably originated from a single transient event, the passage and/or impact of a single large meteorite over the East Antarctic ice sheet. Ar-Ar dating of the tephra layers that bracket the BIT-58 layer should yield a well-constrained age for this event. References: [1] Dunbar N. W. et al. (1995) Abstracts for IUGG XXI General Assembly, in press. [2] Dunbar N. W. et al. (1995) Intl. Symp. Antarc. Earth Sciences VII, in press. [3] Jarosewich E. (1990) Meteoritics, 25, 323-338. Table 1 shows a comparison between average bulk major element composition of debris layer spherules and H chondrite falls. +/- values represent sample standard deviation.
Excess argon in melt inclusions in zero-age anorthoclase feldspar from Mt. Erebus, Antarctica, as revealed by the 40 Ar/ 39 Ar method *1
Geochim Cosmochim Acta, 1997
Historically erupted (1984) anorthoclase phenocrysts from Mt. Erebus yield K/Ar and 40Ar/40Ar app... more Historically erupted (1984) anorthoclase phenocrysts from Mt. Erebus yield K/Ar and 40Ar/40Ar apparent ages as old as 700 ka indicating the presence of excess argon. 40Ar/39Ar furnace step heating results from anorthoclase reveal a positive correlation between the Cl/K ratio and apparent age. Because chlorine (up to 1700 ppm) is present in melt inclusions but not in the anorthoclase crystal lattice, this correlation suggests that the excess argon is associated with melt inclusions trapped within the anorthoclase during rapid crystal growth. Confirmation of the source of excess argon comes from step-heating experiments on multiple anorthoclase aliquots separated from two phenocrysts and one glass aliquot prepared from the matrix of a volcanic bomb. The anorthoclase phenocrysts were crushed and HF etched to yield aliquots containing 30%, 10%, and 1 % melt inclusions. The step-heated anorthoclase with 30% and 10% melt inclusions yielded the highest Cl/K ratios and apparent integrated ages of 640 ± 30 ka and 179 ± 16 ka, respectively. The anorthoclase with I% melt inclusions yielded significantly lower Cl/K ratios and apparent integrated ages of 48 ± 8 ka and 50 ± 30 ka. The step-heated volcanic glass yielded the least variable Cl/K ratios and a total gas age of 101 ± 16 ka. Argon released from the anorthoclase and the trapped melt inclusions can be distinguished by differences in their degassing behavior, allowing geologically more reasonable ages to be obtained. Melt inclusions exposed on the exterior of anorthoclase grains principally degas during furnace extraction at temperatures less than 1200°C. Inclusions entirely within anorthoclase grains principally degas at temperatures greater than 1200°C when incongruent melting of the anorthoclase allows melt inclusion hosted excess argon to escape. Anorthoclase aliquots prepared with less than 1% inclusions can be fitted with a plateau for heating steps below 1200°C to yield ages as young as 8 ± 2 ka, whereas steps above 1200°C yield ages in excess of 100 ka. However, anorthoclase aliquots containing 10-30% melt inclusions yield ages in excess of 200 ka for heating steps below 1200°C. Minimizing the effects of the excess argon from melt inclusions relies on sample preparation and step-heating. Fine crushing and treatment with hydrofluoric acid removes many of the larger melt inclusions. Small melt inclusions which remain within the anorthoclase degas primarily at temperatures above 1200°C. Temperatures below 1200°C yield the most accurate ages. Attempts at post-analytically correcting for the chlorine-correlated excess argon are hindered by the variations in 40Ar E/Cl within and between samples. Elevated 40Ar E/Cl ratios in bubbles within the melt inclusions, as deduced from in vacuo crushing experiments, are the most likely cause for some or all of a sample's total 40Ar E/Cl variation. In addition, relative solubilities of argon and chlorine within phonolitic melts may be partly responsible for variations in 40Ar E/Cl.
Eos, Transactions American Geophysical Union, 2004
Palaeogeography Palaeoclimatology Palaeoecology, 2006
Terrestrial volcanism occurred extensively on Brabant Island, northern Antarctic Peninsula, durin... more Terrestrial volcanism occurred extensively on Brabant Island, northern Antarctic Peninsula, during the Late Quaternary (<200 ka; probably entirely Late Pleistocene). Two compositionally distinct volcanic sequences formed three large shield volcanoes. The volcanoes were constructed in association with a <150 m-thick, non-ice stream glacial cover, although it was likely to be thicker (few hundred metres) where it extended onto the continental
40Ar/39Ar and U-Pb geochronology, geochemistry, and tectonic setting of three episodes of Cretaceous-Eocene calc-alkaline magmatism in the Lake Clark Region, southwestern Alaska
Special Paper 431: Tectonic Growth of a Collisional Continental Margin: Crustal Evolution of Southern Alaska, 2007
... Matthew Heizler Richard Esser New Mexico Bureau of Geology and Mineral Resources, Socorro, Ne... more ... Matthew Heizler Richard Esser New Mexico Bureau of Geology and Mineral Resources, Socorro, New Mexico 87801, USA ... igneous rocks in southwestern Alaska generally are postulated to be related to arc magmatism (Hudson, 1979, 1983; Miller, 1994; Moll-Stalcup, 1994). ...
Mitigation planning for large-scale storage projects: multiple injection zones and reservoir pressure reduction engineering design
Energy Procedia, 2009
Effective mitigation plans are an absolutely critical component of mitigation plans for commercia... more Effective mitigation plans are an absolutely critical component of mitigation plans for commercial-scale geologic carbon sequestration. One fundamental component of mitigation engineering design is immediate reduction of reservoir pressure. The Southwest Regional Partnership on Carbon Sequestration (SWP) is employing immediate reservoir pressure reduction as a primary mitigation tool in our geologic sequestration field projects. We are also employing multiple injection
Role of correlation structures of permeability field on residual trapping mechanisms and buoyancy-driven CO2 migration
Energy Procedia, 2009
Previous research suggests that for many geological CO2 sequestration reservoirs, up to 60% of th... more Previous research suggests that for many geological CO2 sequestration reservoirs, up to 60% of the injected CO2 will be trapped by capillary forces (irreducible saturation), a mechanism termed residual CO2 trapping. More specifically, our recent models of ongoing field tests of geological sequestration suggest that residual CO2 trapping can be maximized if the CO2 plume rises a greater distance due to buoyancy
CO{sub 2} Sequestration Capacity and Associated Aspects of the Most Promising Geologic Formations in the Rocky Mountain Region: Local-Scale Analyses
Rocky Mountain Regional CO{sub 2} Storage Capacity and Significance
Transport in Porous Media, 2011
The primary purpose of this study is to understand quantitative characteristics of mobile, residu... more The primary purpose of this study is to understand quantitative characteristics of mobile, residual, and dissolved CO 2 trapping mechanisms within ranges of systematic variations in different geologic and hydrologic parameters. For this purpose, we conducted an extensive suite of numerical simulations to evaluate the sensitivities included in these parameters. We generated two-dimensional numerical models representing subsurface porous media with various permutations of vertical and horizontal permeability (k v and k h ), porosity (φ), maximum residual CO 2 saturation (S max gr ), and brine density (ρ br ). Simulation results indicate that residual CO 2 trapping increases proportionally to k v , k h , S max gr and ρ br but is inversely proportional to φ. In addition, the amount of dissolution-trapped CO 2 increases with k v and k h , but does not vary with φ, and decreases with S max gr and ρ br . Additionally, the distance of buoyancy-driven CO 2 migration increases proportionally to k v and ρ br only and is inversely proportional to k h , φ, and S max gr . These complex behaviors occur because the chosen sensitivity parameters perturb the distances of vertical and horizontal CO 2 plume migration, pore volume size, and fraction of trapped CO 2 in both pores and formation fluids. Finally, in an effort to characterize complex relationships among residual CO 2 trapping and buoyancy-driven CO 2 migration, we quantified three characteristic zones. Zone I, expressing gr and k h , represents the optimized conditions for geologic CO 2 sequestration. Zone II, showing the variation of φ, would be preferred for secure CO 2 sequestration since CO 2 has less potential to escape from the target formation. In zone III, both residual CO 2 trapping and buoyancy-driven migration distance increase with k v and ρ br .
Six million years of glacial history recorded in volcanic lithofacies of the James Ross Island Volcanic Group, Antarctic Peninsula
Palaeogeography, Palaeoclimatology, Palaeoecology, 2008
... less well appreciated that palaeoenvironmental information is also commonly retained by volca... more ... less well appreciated that palaeoenvironmental information is also commonly retained by volcanoes (especially mafic volcanoes: Smellie, in press) that interacted with a glacial cover (eg [Smellie et al., 1993] , [Smellie, 2000] , [Smellie, 2006] , [Wilch and McIntosh, 2000] , [Wilch ...
Palaeogeography, Palaeoclimatology, Palaeoecology, 2006
New outcrops of Late Neogene sedimentary deposits discovered on James Ross and Vega islands, nort... more New outcrops of Late Neogene sedimentary deposits discovered on James Ross and Vega islands, northern Antarctic Peninsula, are fossiliferous and contain mainly fragmented pectinids amongst other as yet unstudied biota. The sedimentary deposits are interbedded with fresh volcanic units, thus providing the unusual opportunity to investigate the ages of the sedimentary rocks using two independent isotopic systems ( 40 Ar/ 39 Ar and 87 Sr/ 86 Sr). The fossils record past periods of warmer conditions (interglacials) like today. However, our results demonstrate unequivocally that some of the macrofossils present in the sedimentary rocks are reworked and the host sediments are, in these cases, much younger than the ages of their included fossils would suggest. Nevertheless, the Sr ages date these records of interglacial events in the region independently of the age of the strata in which they occur. Conversely, the volcanic rocks show abundant field evidences that they are coeval with the underlying sedimentary deposits, and hence their Ar ages reliably date the timing of their deposition. Our results indicate that at least three generally warmer periods are represented in the James Ross Island region: at 6.5-5.9, 5.03-4.22 and< 0.88 Ma, although our data do not have the resolution for identifying Milankovitch-scale cyclicity. However, the Early Pliocene warm period is particularly well represented and the James Ross Island data may well be capturing a higher proportion of the longer-lasting interglacials that characterised that period. We also present evidence for an interglacial in the Late Pliocene (at 2.54 + 0.86/− 0.36 Ma). Our data suggest that both Antarctic Peninsula and the East Antarctic ice sheets responded in a similar way to long-term regional shifts in climate, but the Antarctic Peninsula is more sensitive to short-term warming, as occurs today.
Journal of Petrology, 2006
Meteoritic event recorded in Antarctic ice
Geology, 1998
Page 1. Geology doi: 10.1130/0091-7613(1998)026<0607:MERIAI>2.3.CO;2 1998;26;607-61... more Page 1. Geology doi: 10.1130/0091-7613(1998)026<0607:MERIAI>2.3.CO;2 1998;26;607-610 Geology Taylor and Marc W. Caffee Ralph P. Harvey, Nelia W. Dunbar, William C. McIntosh, Richard P. Esser, Kuni Nishiizumi, Susan Meteoritic event recorded in Antarctic ice ...
Physical setting and tephrochronology of the summit caldera ice record at Mount Moulton, West Antarctica
Geological Society of America Bulletin, 2008
Skip to main page content. ...
Excess argon in melt inclusions in zero-age anorthoclase feldspar from Mt. Erebus, Antarctica, as revealed by the method
Geochimica et Cosmochimica Acta, 1997
... Kyle PR, Moore JA, and Thirlwall MF (1992) Petrologic Evo lution of Anorthoclase Phonolite La... more ... Kyle PR, Moore JA, and Thirlwall MF (1992) Petrologic Evo lution of Anorthoclase Phonolite Lavas at Mount Erebus, Ross Island, Antarctica. J. Petrol. 33, 849875. McDougall I. (1981) 4)Ar 39Ar age spectra from the KBS Tuff, Koobi Fora, Lake Turkana, northern Kenya. ...
40Ar/39Ar dating of the eruptive history of Mount Erebus, Antarctica: summit flows, tephra, and caldera collapse
Bulletin of Volcanology, 2004
Abstract Eruptive activity has occurred in the summit region of Mount Erebus over the last 95 ky,... more Abstract Eruptive activity has occurred in the summit region of Mount Erebus over the last 95 ky, and has in- cluded numerous lava flows and small explosive erup- tions, at least one plinian eruption, and at least one and probably ...
Antarctic Science, 2005
A revised stratigraphy of Cenozoic volcanic outcrops in the Brandy Bay area on James Ross Island ... more A revised stratigraphy of Cenozoic volcanic outcrops in the Brandy Bay area on James Ross Island is obtained by combining palaeomagnetic and stratigraphical anlysis with 40 Ar/ 39 Ar dating. The fieldwork was carried out between January and March 2002. Oriented palaeomagnetic samples were obtained from 17 volcanic units, the majority of samples being from lava-fed deltas. Individually the deltas are a few to several hundred metres thick and were formed during voluminous basaltic eruptions within an ice sheet or in a marine setting. Out of the sampled units, 15 carry a stable primary magnetization; six were of normal polarity and nine were reversely magnetized. Our 40 Ar/ 39 Ar dating constrains the emplacement of most of the Brandy Bay basalts to the Gilbert chron, with the youngest dated unit having an age of 3.95 Ma and the oldest 6.16 Ma. The mean palaeomagnetic field direction from 14 units has an inclination I = -76°a nd declination D = 352°, α 95 = 7°. The results further suggest that the lava caps on some of the deltas have high remanent intensity and should generate recognizable aeromagnetic anomalies. The combination of palaeomagnetic and isotopic analysis with field mapping methods in a single field area is unique in Antarctica so far and demonstrates that the combination can yield rigorous local stratigraphy in a geographically remote volcanic terrain having discontinuous outcrops.
A Meteoritic Event Layer in Antarctic Ice
Meteoritics, Aug 30, 1995
Where the East Antarctic ice sheet meets the Transantarctic Mountains, old, deep glacial ice is t... more Where the East Antarctic ice sheet meets the Transantarctic Mountains, old, deep glacial ice is tilted upward and exposed.Within this visible cross-section of the ice sheet, layers of dark volcanic tephra serve as stratigraphic markers and datable age horizons [1,2]. Systematic sampling of these layers at a well-known meteorite collection site (the Allan Hills Main icefield) has revealed a band consisting of unusually dark and rounded particles, many of which are spheroidal. This debris layer (BIT- 58) extends parallel to the stratigraphy of the ice established from the tephra bands, and thus apparently marks a single depositional event. Several kg of ice from two sites along this band were subsequently collected and melted, yielding a few grams of sediment for further study. Microscopic examination of sieved samples reveals that roughly 95% of the particles consist of a singular olivine-rich hyaloclastic litholo gy; more that 40% of these are spheroidal. The remaining 5% of the sediment consists of grains derived from local bedrock exposures. Particles range in size from sub-micrometer to over 100 micrometers in diameter, with a strong mode around 85 micrometers suggesting sorting by aeolian processes. However, preservation of delicate particle morphologies such as small parasitic spheres suggests that saltation and/or abrasion was limited. A representative group of particles was mounted in epoxy and sectioned for subsequent electron microprobe analysis. All particles show a mixture of three dominant phases; euhedral and/or skeletal olivine, an Fe-rich glass mesostasis, and abundant Fe-Ni opaques (mostly metals and sulfides). There is a strong correlation between particle shape and the size of olivine grains: angular particles contain larger, more distinct (presumably relict) grains, while the most spheroidal particles are so fine-grained they appear homogenous at this scale. Defocused beam major-element analyses of spheroidal particles show good agreement with bulk H chondrite composition (Table 1). Euhedral olivine grains also correspond to typical H-chondrite composition with Mg-rich cores around 17% Fa zoned to rims of 24% Fa near contact with Fe-rich glass. Opaques include some relatively exotic Ni-rich phases, such as a Ni3S2 / gamma Ni,Fe assemblage. Although direct evidence of an extraterrestrial origin for this debris layer (such as the presence of cosmogenic 10Be and 26Al ) has not yet been obtained, the available data strongly suggest that this sediment originated as meteoritic spallation debris. This debris is distinct from other Antarctic "cosmic dust" collections by virtue of its uniform, recognizable ordinary chondrite composition and the consistent relation shown between grain- size and texture. The BIT-58 layer probably originated from a single transient event, the passage and/or impact of a single large meteorite over the East Antarctic ice sheet. Ar-Ar dating of the tephra layers that bracket the BIT-58 layer should yield a well-constrained age for this event. References: [1] Dunbar N. W. et al. (1995) Abstracts for IUGG XXI General Assembly, in press. [2] Dunbar N. W. et al. (1995) Intl. Symp. Antarc. Earth Sciences VII, in press. [3] Jarosewich E. (1990) Meteoritics, 25, 323-338. Table 1 shows a comparison between average bulk major element composition of debris layer spherules and H chondrite falls. +/- values represent sample standard deviation.
Excess argon in melt inclusions in zero-age anorthoclase feldspar from Mt. Erebus, Antarctica, as revealed by the 40 Ar/ 39 Ar method *1
Geochim Cosmochim Acta, 1997
Historically erupted (1984) anorthoclase phenocrysts from Mt. Erebus yield K/Ar and 40Ar/40Ar app... more Historically erupted (1984) anorthoclase phenocrysts from Mt. Erebus yield K/Ar and 40Ar/40Ar apparent ages as old as 700 ka indicating the presence of excess argon. 40Ar/39Ar furnace step heating results from anorthoclase reveal a positive correlation between the Cl/K ratio and apparent age. Because chlorine (up to 1700 ppm) is present in melt inclusions but not in the anorthoclase crystal lattice, this correlation suggests that the excess argon is associated with melt inclusions trapped within the anorthoclase during rapid crystal growth. Confirmation of the source of excess argon comes from step-heating experiments on multiple anorthoclase aliquots separated from two phenocrysts and one glass aliquot prepared from the matrix of a volcanic bomb. The anorthoclase phenocrysts were crushed and HF etched to yield aliquots containing 30%, 10%, and 1 % melt inclusions. The step-heated anorthoclase with 30% and 10% melt inclusions yielded the highest Cl/K ratios and apparent integrated ages of 640 ± 30 ka and 179 ± 16 ka, respectively. The anorthoclase with I% melt inclusions yielded significantly lower Cl/K ratios and apparent integrated ages of 48 ± 8 ka and 50 ± 30 ka. The step-heated volcanic glass yielded the least variable Cl/K ratios and a total gas age of 101 ± 16 ka. Argon released from the anorthoclase and the trapped melt inclusions can be distinguished by differences in their degassing behavior, allowing geologically more reasonable ages to be obtained. Melt inclusions exposed on the exterior of anorthoclase grains principally degas during furnace extraction at temperatures less than 1200°C. Inclusions entirely within anorthoclase grains principally degas at temperatures greater than 1200°C when incongruent melting of the anorthoclase allows melt inclusion hosted excess argon to escape. Anorthoclase aliquots prepared with less than 1% inclusions can be fitted with a plateau for heating steps below 1200°C to yield ages as young as 8 ± 2 ka, whereas steps above 1200°C yield ages in excess of 100 ka. However, anorthoclase aliquots containing 10-30% melt inclusions yield ages in excess of 200 ka for heating steps below 1200°C. Minimizing the effects of the excess argon from melt inclusions relies on sample preparation and step-heating. Fine crushing and treatment with hydrofluoric acid removes many of the larger melt inclusions. Small melt inclusions which remain within the anorthoclase degas primarily at temperatures above 1200°C. Temperatures below 1200°C yield the most accurate ages. Attempts at post-analytically correcting for the chlorine-correlated excess argon are hindered by the variations in 40Ar E/Cl within and between samples. Elevated 40Ar E/Cl ratios in bubbles within the melt inclusions, as deduced from in vacuo crushing experiments, are the most likely cause for some or all of a sample's total 40Ar E/Cl variation. In addition, relative solubilities of argon and chlorine within phonolitic melts may be partly responsible for variations in 40Ar E/Cl.
Eos, Transactions American Geophysical Union, 2004
Palaeogeography Palaeoclimatology Palaeoecology, 2006
Terrestrial volcanism occurred extensively on Brabant Island, northern Antarctic Peninsula, durin... more Terrestrial volcanism occurred extensively on Brabant Island, northern Antarctic Peninsula, during the Late Quaternary (<200 ka; probably entirely Late Pleistocene). Two compositionally distinct volcanic sequences formed three large shield volcanoes. The volcanoes were constructed in association with a <150 m-thick, non-ice stream glacial cover, although it was likely to be thicker (few hundred metres) where it extended onto the continental
40Ar/39Ar and U-Pb geochronology, geochemistry, and tectonic setting of three episodes of Cretaceous-Eocene calc-alkaline magmatism in the Lake Clark Region, southwestern Alaska
Special Paper 431: Tectonic Growth of a Collisional Continental Margin: Crustal Evolution of Southern Alaska, 2007
... Matthew Heizler Richard Esser New Mexico Bureau of Geology and Mineral Resources, Socorro, Ne... more ... Matthew Heizler Richard Esser New Mexico Bureau of Geology and Mineral Resources, Socorro, New Mexico 87801, USA ... igneous rocks in southwestern Alaska generally are postulated to be related to arc magmatism (Hudson, 1979, 1983; Miller, 1994; Moll-Stalcup, 1994). ...
Mitigation planning for large-scale storage projects: multiple injection zones and reservoir pressure reduction engineering design
Energy Procedia, 2009
Effective mitigation plans are an absolutely critical component of mitigation plans for commercia... more Effective mitigation plans are an absolutely critical component of mitigation plans for commercial-scale geologic carbon sequestration. One fundamental component of mitigation engineering design is immediate reduction of reservoir pressure. The Southwest Regional Partnership on Carbon Sequestration (SWP) is employing immediate reservoir pressure reduction as a primary mitigation tool in our geologic sequestration field projects. We are also employing multiple injection
Role of correlation structures of permeability field on residual trapping mechanisms and buoyancy-driven CO2 migration
Energy Procedia, 2009
Previous research suggests that for many geological CO2 sequestration reservoirs, up to 60% of th... more Previous research suggests that for many geological CO2 sequestration reservoirs, up to 60% of the injected CO2 will be trapped by capillary forces (irreducible saturation), a mechanism termed residual CO2 trapping. More specifically, our recent models of ongoing field tests of geological sequestration suggest that residual CO2 trapping can be maximized if the CO2 plume rises a greater distance due to buoyancy
CO{sub 2} Sequestration Capacity and Associated Aspects of the Most Promising Geologic Formations in the Rocky Mountain Region: Local-Scale Analyses
Rocky Mountain Regional CO{sub 2} Storage Capacity and Significance
Transport in Porous Media, 2011
The primary purpose of this study is to understand quantitative characteristics of mobile, residu... more The primary purpose of this study is to understand quantitative characteristics of mobile, residual, and dissolved CO 2 trapping mechanisms within ranges of systematic variations in different geologic and hydrologic parameters. For this purpose, we conducted an extensive suite of numerical simulations to evaluate the sensitivities included in these parameters. We generated two-dimensional numerical models representing subsurface porous media with various permutations of vertical and horizontal permeability (k v and k h ), porosity (φ), maximum residual CO 2 saturation (S max gr ), and brine density (ρ br ). Simulation results indicate that residual CO 2 trapping increases proportionally to k v , k h , S max gr and ρ br but is inversely proportional to φ. In addition, the amount of dissolution-trapped CO 2 increases with k v and k h , but does not vary with φ, and decreases with S max gr and ρ br . Additionally, the distance of buoyancy-driven CO 2 migration increases proportionally to k v and ρ br only and is inversely proportional to k h , φ, and S max gr . These complex behaviors occur because the chosen sensitivity parameters perturb the distances of vertical and horizontal CO 2 plume migration, pore volume size, and fraction of trapped CO 2 in both pores and formation fluids. Finally, in an effort to characterize complex relationships among residual CO 2 trapping and buoyancy-driven CO 2 migration, we quantified three characteristic zones. Zone I, expressing gr and k h , represents the optimized conditions for geologic CO 2 sequestration. Zone II, showing the variation of φ, would be preferred for secure CO 2 sequestration since CO 2 has less potential to escape from the target formation. In zone III, both residual CO 2 trapping and buoyancy-driven migration distance increase with k v and ρ br .
Six million years of glacial history recorded in volcanic lithofacies of the James Ross Island Volcanic Group, Antarctic Peninsula
Palaeogeography, Palaeoclimatology, Palaeoecology, 2008
... less well appreciated that palaeoenvironmental information is also commonly retained by volca... more ... less well appreciated that palaeoenvironmental information is also commonly retained by volcanoes (especially mafic volcanoes: Smellie, in press) that interacted with a glacial cover (eg [Smellie et al., 1993] , [Smellie, 2000] , [Smellie, 2006] , [Wilch and McIntosh, 2000] , [Wilch ...
Palaeogeography, Palaeoclimatology, Palaeoecology, 2006
New outcrops of Late Neogene sedimentary deposits discovered on James Ross and Vega islands, nort... more New outcrops of Late Neogene sedimentary deposits discovered on James Ross and Vega islands, northern Antarctic Peninsula, are fossiliferous and contain mainly fragmented pectinids amongst other as yet unstudied biota. The sedimentary deposits are interbedded with fresh volcanic units, thus providing the unusual opportunity to investigate the ages of the sedimentary rocks using two independent isotopic systems ( 40 Ar/ 39 Ar and 87 Sr/ 86 Sr). The fossils record past periods of warmer conditions (interglacials) like today. However, our results demonstrate unequivocally that some of the macrofossils present in the sedimentary rocks are reworked and the host sediments are, in these cases, much younger than the ages of their included fossils would suggest. Nevertheless, the Sr ages date these records of interglacial events in the region independently of the age of the strata in which they occur. Conversely, the volcanic rocks show abundant field evidences that they are coeval with the underlying sedimentary deposits, and hence their Ar ages reliably date the timing of their deposition. Our results indicate that at least three generally warmer periods are represented in the James Ross Island region: at 6.5-5.9, 5.03-4.22 and< 0.88 Ma, although our data do not have the resolution for identifying Milankovitch-scale cyclicity. However, the Early Pliocene warm period is particularly well represented and the James Ross Island data may well be capturing a higher proportion of the longer-lasting interglacials that characterised that period. We also present evidence for an interglacial in the Late Pliocene (at 2.54 + 0.86/− 0.36 Ma). Our data suggest that both Antarctic Peninsula and the East Antarctic ice sheets responded in a similar way to long-term regional shifts in climate, but the Antarctic Peninsula is more sensitive to short-term warming, as occurs today.
Journal of Petrology, 2006
Meteoritic event recorded in Antarctic ice
Geology, 1998
Page 1. Geology doi: 10.1130/0091-7613(1998)026<0607:MERIAI>2.3.CO;2 1998;26;607-61... more Page 1. Geology doi: 10.1130/0091-7613(1998)026<0607:MERIAI>2.3.CO;2 1998;26;607-610 Geology Taylor and Marc W. Caffee Ralph P. Harvey, Nelia W. Dunbar, William C. McIntosh, Richard P. Esser, Kuni Nishiizumi, Susan Meteoritic event recorded in Antarctic ice ...
Physical setting and tephrochronology of the summit caldera ice record at Mount Moulton, West Antarctica
Geological Society of America Bulletin, 2008
Skip to main page content. ...
Excess argon in melt inclusions in zero-age anorthoclase feldspar from Mt. Erebus, Antarctica, as revealed by the method
Geochimica et Cosmochimica Acta, 1997
... Kyle PR, Moore JA, and Thirlwall MF (1992) Petrologic Evo lution of Anorthoclase Phonolite La... more ... Kyle PR, Moore JA, and Thirlwall MF (1992) Petrologic Evo lution of Anorthoclase Phonolite Lavas at Mount Erebus, Ross Island, Antarctica. J. Petrol. 33, 849875. McDougall I. (1981) 4)Ar 39Ar age spectra from the KBS Tuff, Koobi Fora, Lake Turkana, northern Kenya. ...
40Ar/39Ar dating of the eruptive history of Mount Erebus, Antarctica: summit flows, tephra, and caldera collapse
Bulletin of Volcanology, 2004
Abstract Eruptive activity has occurred in the summit region of Mount Erebus over the last 95 ky,... more Abstract Eruptive activity has occurred in the summit region of Mount Erebus over the last 95 ky, and has in- cluded numerous lava flows and small explosive erup- tions, at least one plinian eruption, and at least one and probably ...
Antarctic Science, 2005
A revised stratigraphy of Cenozoic volcanic outcrops in the Brandy Bay area on James Ross Island ... more A revised stratigraphy of Cenozoic volcanic outcrops in the Brandy Bay area on James Ross Island is obtained by combining palaeomagnetic and stratigraphical anlysis with 40 Ar/ 39 Ar dating. The fieldwork was carried out between January and March 2002. Oriented palaeomagnetic samples were obtained from 17 volcanic units, the majority of samples being from lava-fed deltas. Individually the deltas are a few to several hundred metres thick and were formed during voluminous basaltic eruptions within an ice sheet or in a marine setting. Out of the sampled units, 15 carry a stable primary magnetization; six were of normal polarity and nine were reversely magnetized. Our 40 Ar/ 39 Ar dating constrains the emplacement of most of the Brandy Bay basalts to the Gilbert chron, with the youngest dated unit having an age of 3.95 Ma and the oldest 6.16 Ma. The mean palaeomagnetic field direction from 14 units has an inclination I = -76°a nd declination D = 352°, α 95 = 7°. The results further suggest that the lava caps on some of the deltas have high remanent intensity and should generate recognizable aeromagnetic anomalies. The combination of palaeomagnetic and isotopic analysis with field mapping methods in a single field area is unique in Antarctica so far and demonstrates that the combination can yield rigorous local stratigraphy in a geographically remote volcanic terrain having discontinuous outcrops.