Explosive lava-water interactions on Earth and Mars
122
Christopher W. Hamilton [email protected] Hawai‘i Institute of Geophysics and Planetology, University of Hawai‘i Explosive Lava–Water Interactions on Earth and Mars Ph.D. Co-Advisor: Thor Thordarson Co-Authors: Lionel Wilson Ciarán Beggan Ph.D. Advisor: Sarah Fagents Acknowledgements National Aeronautics and Space Administration Icelandic Centre for Research National Science Foundation Geological Society of America Hawai‘i Geographic Information Coordinating Council University of
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Volcanic rootless constructs (VRCs) are products of explosive lava–water interactions. VRCs are significant because they imply the presence of active lava flows and an underlying aqueous phase (e.g., groundwater or ice) at the time of their formation. This information is valuable for locating fossil hydrothermal systems and exploring the relationships between climate, water stability and abundance, weathering environments, and the development of habitable niches in extraterrestrial environments.The architecture, structure, and emplacement chronology of VRCs in the 1783–1784 Laki lava flow in Iceland were investigated using tephrostratigraphy, Differential Global Positioning System (DGPS) measurements, remote sensing, and Geographic Information Systems (GIS). The geospatial distribution of rootless eruption sites were also analyzed using statistical methods to quantify their patterns of spatial organization and infer the geologic processes of their formation. Employing terrestrially validated morphological and geospatial criteria, analogs to Icelandic VRCs were identified in the Tartarus Colles region of Mars. The VRC groups and associated geologic units were mapped using remote sensing and GIS. Impact cratering statistics were used to constrain the age of the VRC groups and thermodynamic models of lava–permafrost interactions were used to estimate paleo-ground ice table depth, calculate mobilized (i.e., melted and/or vaporized) water volumes, and infer obliquity-driven climate conditions.
Transcript of Explosive lava-water interactions on Earth and Mars
Christopher W. [email protected]
Hawai‘i Institute of Geophysics and Planetology, University of Hawai‘i
Explosive Lava–Water Interactions
on Earth and Mars
Ph.D. Co-Advisor: Thor Thordarson
Co-Authors: Lionel Wilson Ciarán Beggan
Ph.D. Advisor: Sarah Fagents
Acknowledgements National Aeronautics and Space Administration Icelandic Centre for Research National Science FoundationGeological Society of AmericaHawai‘i Geographic Information Coordinating Council University of Hawai‘i Graduate Student Organization
Introduction Methods Results Discussion ConclusionsIntroduction Earth Mars Discussion Conclusions
3. Thermodynamic modeling
1. Geological mapping and geomorphology
2. Statistical nearest neighbor (NN) analysis
Explosive Lava–Water Interactions
Introduction Methods Results Discussion ConclusionsIntroduction Earth Mars Discussion Conclusions
Explosive Lava–Water InteractionsEarth:
Hamilton CW, T Thordarson, and SA Fagents (2010a) Explosive lava-water interactions I: architecture and emplacement chronology of volcanic rootless cone groups in the 1783- 1784 Laki lava flow. Bulletin of Volcanology, 10.1007/s00445-009-0330-6.
Hamilton CW, SA Fagents, and T Thordarson (2010b) Explosive lava-water interaction II: Self-organization processes among volcanic rootless eruption sites in the 1783-1784 Laki lava flow, Iceland. Bulletin of Volcanology, 10.1007/s00445-009-0331-5.
Mars:Hamilton CW, SA Fagents, and L Wilson (2010c) Explosive lava-water interactions in Elysium
Planitia, Mars: constraints on the formation of the Tartarus Colles cone groups. Journal of Geophysical Research, (in press).
Hamilton CW, SA Fagents, and T Thordarson (2010d) Lava-ground ice interactions in Elysium Planitia, Mars: geomorphological and geospatial analysis of the western Tartarus Colles cone groups. Journal of Geophysical Research, (in review).
Introduction Methods Results Discussion ConclusionsIntroduction Earth Mars Discussion Conclusions
Introduction
Lake Mývatn, Iceland
Volcano–H2O Interactions
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Volcanic Rootless Cones (VRCs)
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Skaftá River, Iceland
Volcanic Rootless Cones (VRCs)
VRC group in the Laki lava flow, Iceland
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Volcanic Rootless Cones (VRCs)
Introduction Earth Mars Discussion Conclusions
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100 m
VRC group in the Laki lava flow, Iceland
Volcanic Rootless Cones (VRCs)
Conceptual Model
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Conceptual Model
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Conceptual Model
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Conceptual Model
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Conceptual Model
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Conceptual Model
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Conceptual Model
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Conceptual Model
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Conceptual Model
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Conceptual Model
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Conceptual Model
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Conceptual Model
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Conceptual Model
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Conceptual Model
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Conceptual Model
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Conceptual Model
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Conceptual Model
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Conceptual Model
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Conceptual Model
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Conceptual Model
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Neural Networks
VRC cross-section within Rauðhólar, Iceland
Introduction Methods Results Discussion ConclusionsIntroduction Earth Mars Discussion Conclusions
Volcanic Rootless Cones (VRCs)
Neural Networks
VRC cross-section within Rauðhólar, Iceland
Introduction Methods Results Discussion ConclusionsIntroduction Earth Mars Discussion Conclusions
Volcanic Rootless Cones (VRCs)
Neural Networks
VRC cross-section within Rauðhólar, Iceland
Introduction Methods Results Discussion ConclusionsIntroduction Earth Mars Discussion Conclusions
Volcanic Rootless Cones (VRCs)
Neural Networks
VRC cross-section within Rauðhólar, Iceland
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Volcanic Rootless Cones (VRCs)
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Volcanic Rootless Cones (VRCs)
1 km
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VRC analogs among the western Tartarus Colles cone groups, Mars
Volcanic Rootless Cones (VRCs)
1 km
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Volcanic Rootless Cones (VRCs)
VRC analogs among the eastern Tartarus Colles cone groups, Mars
Mars Exploration Rover Spirit images of volcanic rocks in Gusev Crater, Mars
Volcano–H2O Interactions on Mars
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Mars Exploration Rover Spirit images of volcanic rocks in Gusev Crater, Mars
Volcano–H2O Interactions on Mars
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Mars Exploration Rover Spirit images of volcanic rocks in Gusev Crater, Mars
Volcano–H2O Interactions on Mars
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Volcanic Rootless Cones (VRCs)
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Mars Exploration Program Goals:1. Determine if life ever arose on Mars
2. Climate processes and history
3. Evolution of the surface and interior
4. Prepare for human exploration
Fossil hydrothermal systems
Obliquity-driven ground ice stability
Volcanic and magmatic processes
Identification of water resources
Introduction Methods Results Discussion ConclusionsIntroduction Earth Mars Discussion Conclusions
Earth
Terrestrial Analog: Laki, Iceland
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N
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N
Terrestrial Analog: Laki, Iceland
1070ºC
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Rootless Cone Archetypes Brittle Crust
Viscous Layer
Molten Core Saturated
Unsaturated
Lava Flow Sediments
800ºC
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Rootless Cone Archetypes
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Rootless Cone Archetypes
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Rootless Cone Archetypes
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Rootless Cone Archetypes
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Rootless Cone Archetypes
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Geospatial Analysis
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Hekla 1104 pumice layer
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Geospatial Analysis
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Kipuka Mantled Terrain
Lava Rootless Cone Crater Crater Floor
1000 m
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Geospatial Analysis
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Geospatial Analysis
○
e
a
R
RR
Ra: mean actual distance between Nearest Neighbor (NN) pairs
Re: mean expected distance between NNs
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Geospatial Analysis
if R < 1 then clustered if R ≈ 1 then random if R > 1 then repelled
R: 1.00
|c|: 0.05
R: 1.91
|c|: 6.64
R: 0.47
|c|: 7.13
Clustered Poisson (Random) Evenly Spacedx
R < 1 R = 1 R > 1
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Geospatial Analysis
Figure adapted from Bruno et al. (2006)
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Geospatial Analysis
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Geospatial Analysis
Population size (N)
Repelled
Clustered
Discharge from extraction wellMaximum radius of influenceDistance from extraction wellAquifer thicknessWater saturated depth at rWater table draw down at r
QRrHhS
Introduction Methods Results Discussion ConclusionsIntroduction Earth Mars Discussion Conclusions
Geospatial Analysis
Discharge from extraction wellMaximum radius of influenceDistance from extraction wellAquifer thicknessWater saturated depth at rWater table draw down at r
QRrHhS
Introduction Methods Results Discussion ConclusionsIntroduction Earth Mars Discussion Conclusions
Geospatial Analysis
Discharge from extraction wellMaximum radius of influenceDistance from extraction wellAquifer thicknessWater saturated depth at rWater table draw down at r
QRrHhS
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Geospatial Analysis
3. Sample-size-dependent organization
1. Lava pathways effect VRC morphology
2. VRC groups are diachronous constructs
Introduction Methods Results Discussion ConclusionsIntroduction Earth Mars Discussion Conclusions
Summary
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Mars
Tartarus Colles Cone Groups, Mars
MOLA Digital Terrain Model of Elysium Planitia, Mars
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Tartarus Colles Cone Groups, Mars
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Tartarus Colles Cone Groups, Mars Cerberus Fossae 3 unit
Late AmazonianCerberus Fossae 2 unitLate to Middle Amazonian
Elysium Rise unitEarly Amazonian to Early Hesperian
Crater unitLate Amazonian to Early Hesperian
Arcadia Planitia unitLate to Early Hesperian
Nepenthes Mensae unitEarly Hesperian to Early Noachian
Noachian Hesperian Amazonian
3.5 1.8 0 Billions of years before present
Introduction Methods Results Discussion ConclusionsIntroduction Earth Mars Discussion Conclusions
Tartarus Colles Cone Groups, Mars
Elysium Rise unitEarly Amazonian to Early Hesperian
Nepenthes Mensae unitEarly Hesperian to Early Noachian
VRC-hosting Tartarus Colles lava
Shield-like Tartarus Colles lava
Elevation (m)
Noachian Hesperian Amazonian
3.5 1.8 0 Billions of years before present
Introduction Methods Results Discussion ConclusionsIntroduction Earth Mars Discussion Conclusions
Tartarus Colles Cone Groups, Mars
Elysium Rise unitEarly Amazonian to Early Hesperian
Nepenthes Mensae unitEarly Hesperian to Early Noachian
VRC-hosting Tartarus Colles lava
Shield-like Tartarus Colles lava
VRCs
Elevation (m)
Noachian Hesperian Amazonian
3.5 1.8 0 Billions of years before present
Introduction Methods Results Discussion ConclusionsIntroduction Earth Mars Discussion Conclusions
Tartarus Colles Cone Groups, Mars
Elysium Rise unitEarly Amazonian to Early Hesperian
Nepenthes Mensae unitEarly Hesperian to Early Noachian
VRC-hosting Tartarus Colles lava
Shield-like Tartarus Colles lava
VRCs
Elevation (m)
Noachian Hesperian Amazonian
3.5 1.8 0 Billions of years before present
Introduction Methods Results Discussion ConclusionsIntroduction Earth Mars Discussion Conclusions
Tartarus Colles Cone Groups, Mars
Elysium Rise unitEarly Amazonian to Early Hesperian
Nepenthes Mensae unitEarly Hesperian to Early Noachian
VRC-hosting Tartarus Colles lava
Shield-like Tartarus Colles lava
VRCs
Elevation (m)
Pitted terrain
Noachian Hesperian Amazonian
3.5 1.8 0 Billions of years before present
Introduction Methods Results Discussion ConclusionsIntroduction Earth Mars Discussion Conclusions
Tartarus Colles Cone Groups, Mars
Elysium Rise unitEarly Amazonian to Early Hesperian
VRC-hosting Tartarus Colles lavaLate to Middle Amazonian (75–250 Ma)
(log Ni)
Nearest Neighbor (NN) Results
Introduction Methods Results Discussion ConclusionsIntroduction Earth Mars Discussion Conclusions
Repelled
Clustered
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Nearest Neighbor (NN) Results
Repelled
Clustered
Nearest Neighbor (NN) Results
Introduction Methods Results Discussion ConclusionsIntroduction Earth Mars Discussion Conclusions
Repelled
Clustered
(log Ni)
Nearest Neighbor (NN) Results
Introduction Methods Results Discussion ConclusionsIntroduction Earth Mars Discussion Conclusions
Repelled
Clustered
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Nearest Neighbor (NN) Results
Lava Thickness
N
10 km
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Nearest Neighbor (NN) Results
Lava Thickness
N
10 km
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Nearest Neighbor (NN) Results
Lava Thickness
N
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Nearest Neighbor (NN) Results
3 km
Lava Thickness
N
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3 km
3 km
Lava Thickness
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N
10 km
Nearest Neighbor (NN) Results
Thermodynamic Model
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Thermodynamic Model
Differences in isotherm depths on Mars and the Earth
Mars (TA = 210 K) Earth (TA = 270 K)
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Thermodynamic Model
Hydrothermal system longevity (substrate temperature >273 K)
Mars (TA = 210 K) Earth (TA = 270 K)
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Thermodynamic Model
X Y
X Y
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X
Y
Thermodynamic Model
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X Y
X Y X Y
X
Y
Thermodynamic Model
273 K at TL = 1273 K
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X Y
X Y X Y
X
Y
Thermodynamic Model
273 K at TL = 1273 K
Maximum 273 K
Introduction Methods Results Discussion ConclusionsIntroduction Earth Mars Discussion Conclusions
X Y
X Y X Y
X
Y
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Discussion
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Summary
Introduction Methods Results Discussion ConclusionsIntroduction Earth Mars Discussion Conclusions
Summary
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Summary
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Summary
Summary
Introduction Methods Results Discussion ConclusionsIntroduction Earth Mars Discussion Conclusions
Introduction Methods Results Discussion ConclusionsIntroduction Earth Mars Discussion Conclusions
SummaryMinimum H2O volume = (VRC domain area) × (Isotherm depth at TL = 1273 K) × (Substrate porosity)
Minimum H2O volume = (2014 km2) x (21 to 42 m for 30 to 60 m-thick lava) × (0.1 to 0.3) Minimum H2O volume = ~3.7 to 22.5 km3
SummaryMinimum H2O volume = (VRC domain area) × (Isotherm depth at TL = 1273 K) × (Substrate porosity)
Minimum H2O volume = (2014 km2) x (21 to 42 m for 30 to 60 m-thick lava) × (0.1 to 0.3) Minimum H2O volume = ~3.7 to 22.5 km3
Paleo-climate = intermediate obliquity (~35°) 75–250 Ma ago, with excursions to ~25–32°
Introduction Methods Results Discussion ConclusionsIntroduction Earth Mars Discussion Conclusions
SummaryMinimum H2O volume = (VRC domain area) × (Isotherm depth at TL = 1273 K) × (Substrate porosity)
Minimum H2O volume = (2014 km2) x (21 to 42 m for 30 to 60 m-thick lava) × (0.1 to 0.3) Minimum H2O volume = ~3.7 to 22.5 km3
Paleo-climate = intermediate obliquity (~35°) 75–250 Ma ago, with excursions to ~25–32°
Hydrothermal system longevity = up to ~1300 years for 75 m-thick lava and TA = 210 K
Introduction Methods Results Discussion ConclusionsIntroduction Earth Mars Discussion Conclusions
Conclusions
Introduction Methods Results Discussion ConclusionsIntroduction Earth Mars Discussion Conclusions
Conclusions
Introduction Methods Results Discussion ConclusionsIntroduction Earth Mars Discussion Conclusions
Lo
cal
Glo
bal
1. How do volcanic rootless constructs (VRCs) form?
VRCs form due to explosive lava–water interactions that indicate at random in favorable environments
VRC groups are diachronous structures with VRCmorphologies recording stages of lava emplacement
Thermokarst can form in association with VRCs ifextended ground ice melting causes lava foundering
Conclusions
Introduction Methods Results Discussion ConclusionsIntroduction Earth Mars Discussion Conclusions
Lo
cal
Glo
bal
1. How do volcanic rootless constructs (VRCs) form?
2. Can rootless cones be identified using geospatial analysis?
VRCs form due to explosive lava–water interactions that indicate at random in favorable environments
VRC groups are diachronous structures with VRCmorphologies recording stages of lava emplacement
Thermokarst can form in association with VRCs ifextended ground ice melting causes lava foundering Rootless eruption sites exhibit scale-dependent variations in nearest neighbor statistics, but cannotbe distinguished using one geospatial parameter
VRCs form due to explosive lava–water interactions that indicate at random in favorable environments
VRC groups are diachronous structures with VRCmorphologies recording stages of lava emplacement
Thermokarst can form in association with VRCs ifextended ground ice melting causes lava foundering Rootless eruption sites exhibit scale-dependent variations in nearest neighbor statistics, but cannotbe distinguished using one geospatial parameter
During VRC formation, the western Tartaus Colles region contained >4–22 km3 H2O, and could have had active hydrothermal systems for up to ~1300 years
This major volcanic event occurred on Mars ~125 Maago, under intermediate (~35°) obliquity conditionssupporting a mid-latitude ice table at <21–42 m depth
Conclusions1. How do volcanic
rootless constructs (VRCs) form?
Lo
cal
Glo
bal
2. Can rootless cones be identified using geospatial analysis?
3. What information do rootless cones provide about the geological evolution of Mars?
Introduction Methods Results Discussion ConclusionsIntroduction Earth Mars Discussion Conclusions
DGPS Mapping
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Terrestrial Analogue: Laki, Iceland
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N
Terrestrial Analogue: Laki, Iceland
Introduction Methods Results Discussion Conclusions
Kipuka Mantled Terrain
Lava Rootless Cone Crater Crater Floor
1000 m
Facies Mapping
Introduction Methods Results Discussion Conclusions
Introduction Methods Results Discussion Conclusions
Facies Mapping
Differential GPS tracks define facies boundaries
15 m
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Facies Mapping
DGPS boundaries were digitized in ArcGIS
15 m
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Facies Mapping
15 m
DGPS boundaries were digitized in ArcGIS
2216 rootless eruptions sites defined using Differential GPS
86 stratigraphic sections used to constrain kipuka locations and emplacement chronology
On Wednesday, August 20, 2008this geological map was usedto prevent renewed quarrying of the Laki rootless cones
Introduction Methods Results Discussion Conclusions
Facies Mapping
0.5 m
1.0 m
Katla 1918
Laki (S2)
Emplacement ChronologyLaki S1a Layer (Fissures 1)June 8, 1783
Laki S1b Layer (Fissures 2)June 10-11, 1783
Laki S2 Layer (Fissure 3)June 14, 1783
Introduction Methods Results Discussion Conclusions
0.5 m
Katla 1918
Laki (S2)
Emplacement Chronology
1.0 m
Laki S1a Layer (Fissures 1)June 8, 1783
Laki S1b Layer (Fissures 2)June 10-11, 1783
Laki S2 Layer (Fissure 3)June 14, 1783
Introduction Methods Results Discussion Conclusions
0.5 m
Katla 1918
Laki (S1 + S2)
Katla 1755
Katla 1625
Emplacement Chronology
1.0 m
Laki S1a Layer (Fissures 1)June 8, 1783
Laki S1b Layer (Fissures 2)June 10-11, 1783
Laki S2 Layer (Fissure 3)June 14, 1783
Introduction Methods Results Discussion Conclusions
Emplacement Chronology
Introduction Methods Results Discussion Conclusions
Nearest Neighbor (NN) Analysis
Introduction Methods Results Discussion Conclusions
○
e
a
R
RR
Ra: mean actual distance between Nearest Neighbor (NN) pairs
Re: mean expected distance between NNs
c: test statistic for measuring the significance of R
σ : standard error of the mean expected NN distance
eR
ea RRc
Re
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Geospatial Analysis
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Geospatial Analysis
Population size (N)
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Geospatial Analysis
Population size (N)
Thermodynamic Modeling
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Thermodynamic Model
t
dx
t
dxerf
t
xerfTTTT BLB 2222
2
1
T = temperature at time t in secondsTL = temperature of the lava (initially equal to TM)TB = temperature at the base of the flow (initially equal to TM)TM = temperature of basaltic magma (1450 or 1617 K)d = depth beneath the top of the flow in metersk = thermal diffusivity (7 × 10-7 m2 s-1)
Other boundary conditions and considerations: 1. Upper flow surface of the lava is kept at ambient temperature (TA) 2. Substrate temperature is initially set to TA
3. k adjusted to account for the heat absorbed in melting and vaporizing H2O
Analytical model:
Introduction Methods Results Discussion Conclusions
Thermodynamic Model
Introduction Methods Results Discussion Conclusions
Effects of ambient temperature (TA) on isotherm depth
Mars (TA = 210 K) Earth (TA = 270 K)
Thermodynamic Model
Introduction Methods Results Discussion Conclusions
Obliquity-Driven Climate Change
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Obliquity-Driven Climate Change
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Probabilistic obliquity scenarios for Mars during the past 250 Ma (Laskar et al., 2004)
Obliquity (Axial Tilt)
Plane of the ecliptic
If ice then obliquity >25°If desiccation then obliquity <32°
