Papers by Francis Karmanocky
Quaternary Science Reviews, Apr 1, 2015
The morphology of beach ridge plains along active margins can be used to reconstruct coastal subs... more The morphology of beach ridge plains along active margins can be used to reconstruct coastal subsidence during large megathrust earthquakes. Here we use satellite imagery and automatic level surveys to reconstruct the build-up of a new beach ridge along a 10 km long stretch of the western Acehnese coast after the complete destruction of the beach during the great Sumatra -Andaman earthquake and successive tsunami in December 2004. The western Acehnese coast is characterized by ridge and swale topography reflecting the long-term progradation of the coastline. Radiocarbon dates obtained from marshy deposits in between ridges indicate an average progradation rate of 1.3e1.8 m per year over the last 1000 years. As a result of coseismic subsidence of 0.5e1 m and tsunami inundation in 2004, the most seaward beach ridge was destroyed and the coastline receded on average 110 m landward representing 65e85 years of average progradation. However, by 2006 a new 22 m wide ridge had formed. In the following years the coast prograded by an additional 30 m, but has not yet recovered to its pre-December 2004 position. In addition to the spatial data, topographic surveys conducted in 2009, 2012 and 2013 indicate that the crest of the newly formed beach ridge is 0.8e1.3 m higher than the crests of older beach ridges further inland. The source material for the new ridge is most likely sand transported seaward by the back flow of the 2004 tsunami and stored on the upper shoreface. In the months and years after the tsunami, this sediment is reworked by regular coastal processes and transported back to shore, leading to the reconstruction of a higher beach ridge in equilibrium with the vertical displacement of the coast and the resulting higher relative sea level. The preservation potential of the newly formed ridge depends on sediment availability within the coastal system to balance coastal profile adjustments due to rapid postseismic uplift. In Aceh, the preservation of seismically modified beach ridge morphology seems likely and another prominent ridge can be found in 640 m distance to the shoreline. It most likely formed in the aftermath of a previous megathrust earthquake and tsunami about 600 years ago matching sediment and coral records for this region.
is situated at high elevation in the Andes Mountains of northern Chile in an extremely arid, smal... more is situated at high elevation in the Andes Mountains of northern Chile in an extremely arid, small, intervolcanic basin and contains pools of acid (pH 3.3 -4.1) saline (5 -30 ppth) water that are precipitating gypsum crystals. Gypsum crystals trap acid saline water from the pools as fluid inclusions. Little research has been conducted on fluid inclusions in gypsum. At Salar Ignorado two types of bottom-growth gypsum form from the surface pools: large bladed and tiny needle-like crystals. Salar Ignorado gypsum contains primary fluid inclusions of three distinct morphologies, oriented parallel to crystal face. Petrography and microthermometry were performed on 27 gypsum crystals from Salar Ignorado. Most primary fluid inclusions are all liquid, however some primary inclusions are composed of liquid and a gas phase. One large gypsum crystal, hosting primary fluid inclusions along 28 successive growth bands, was the focus for fluid inclusion studies. Microthermometric results in geochemical trends. This crystal shows a change in parent fluids, during growth, from low salinity to high salinity to low salinity. At the bottom of the crystal, the lowest six fluid inclusion assemblages have salinities of 1.7 to 5.1 eq. wt. % NaCl. The next nine fluid inclusion assemblages have significantly higher salinity (18.6 and 25.5 eq. wt. % NaCl) inclusions. The twelve fluid inclusion assemblages near the top of the crystal have low salinity (1.6 to 7.9 eq. wt. % NaCl) like those at the bottom of the crystal. The high salinity fluid inclusions in the middle of this gypsum crystal are interpreted as the migration of hydrothermal fluids to the surface, which are intimately linked to the local active magmatism. Secondary evidence of hydrothermal pulses are high molecular weight hydrocarbons and hydrogen sulfide odors upon crushing. A variety of microorganisms are trapped both as solid inclusions and as potentially viable halophilic and acidophilic prokaryotes and eukaryotes within fluid inclusions in this Mars-analog gypsum. Pennate diatoms, green algae, and prokaryotes have been documented in gypsum precipitated from acid (pH 1.8-4.6) saline (5%-28% total dissolved solids) waters at Salar Ignorado and its larger neighbor, Salar Gorbea. Evaluation of Salar Ignorado gypsum indicates that primary fluid inclusions record hydrochemistry and microbiology of various intervals of waters. This study has implications for detailed interpretations of past environments from ancient gypsum in the rock record, as well as clues for the search for life on Mars. This thesis has shown for the first time that primary fluid inclusions in gypsum can serve as proxies for various environmental conditions. Detailed study of Salar Ignorado gypsum has identified trends in surface water salinity, degassing of hydrogen sulfide and hydrocarbons, and fossilization of microorganisms.
Quaternary Science Reviews, 2015
The morphology of beach ridge plains along active margins can be used to reconstruct coastal subs... more The morphology of beach ridge plains along active margins can be used to reconstruct coastal subsidence during large megathrust earthquakes. Here we use satellite imagery and automatic level surveys to reconstruct the build-up of a new beach ridge along a 10 km long stretch of the western Acehnese coast after the complete destruction of the beach during the great Sumatra -Andaman earthquake and successive tsunami in December 2004. The western Acehnese coast is characterized by ridge and swale topography reflecting the long-term progradation of the coastline. Radiocarbon dates obtained from marshy deposits in between ridges indicate an average progradation rate of 1.3e1.8 m per year over the last 1000 years. As a result of coseismic subsidence of 0.5e1 m and tsunami inundation in 2004, the most seaward beach ridge was destroyed and the coastline receded on average 110 m landward representing 65e85 years of average progradation. However, by 2006 a new 22 m wide ridge had formed. In the following years the coast prograded by an additional 30 m, but has not yet recovered to its pre-December 2004 position. In addition to the spatial data, topographic surveys conducted in 2009, 2012 and 2013 indicate that the crest of the newly formed beach ridge is 0.8e1.3 m higher than the crests of older beach ridges further inland. The source material for the new ridge is most likely sand transported seaward by the back flow of the 2004 tsunami and stored on the upper shoreface. In the months and years after the tsunami, this sediment is reworked by regular coastal processes and transported back to shore, leading to the reconstruction of a higher beach ridge in equilibrium with the vertical displacement of the coast and the resulting higher relative sea level. The preservation potential of the newly formed ridge depends on sediment availability within the coastal system to balance coastal profile adjustments due to rapid postseismic uplift. In Aceh, the preservation of seismically modified beach ridge morphology seems likely and another prominent ridge can be found in 640 m distance to the shoreline. It most likely formed in the aftermath of a previous megathrust earthquake and tsunami about 600 years ago matching sediment and coral records for this region.
Widespread subsidence and erosion during the 2004 Sumatra-Andaman earthquake and tsunami displace... more Widespread subsidence and erosion during the 2004 Sumatra-Andaman earthquake and tsunami displaced the coastline in northern Sumatra up to 500 m inland. Satellite images taken in the months and years after the earthquake, however, show that new beaches are rapidly building up. In our study area, the rapid growth of the shoreline is reflected by a characteristic ridge-and-swale topography. Individual beach ridges mark former positions of the shoreline and run parallel to the coast for several kilometers. Older beach ridges can be found further inland whereas new beach ridges build progressively seaward. Radiocarbon dates obtained from marshy deposits in between beach ridges indicate a long-term progradation rate of 1-2 m per year for the last 1000 years. In order to understand short-term progradation, we carried out an auto-level survey and compiled satellite images, aerial photographs and Dutch colonial maps using GIS. Coastal progradation estimated from spatial data over the last 90 years, prior to the 2004 tsunami is 3-4 m per year. During the 2004 earthquake the coastline receded by approximately 200 m, but a new prominent beach ridge built up in only 4 months with growth rates of close to 100 m per year. Recently obtained data shows reduced progradation in the order of 5 m per year for the time period of April 2005 to March 2009. In addition to the horizontal growth pattern, the height of beach ridges can be used to determine changes in relative sea level. Our data shows that prominent beach ridges correlate with large earthquakes along the Sunda Trench subduction zone and can potentially serve as a tool in seismic hazard assessment.
Geological Society of America Abstracts with Programs, 2016
Geofluids, 2016
Salar Ignorado is a shallow acid saline lake hosted by a small intervolcanic basin high in the An... more Salar Ignorado is a shallow acid saline lake hosted by a small intervolcanic basin high in the Andes Mountains of northern Chile. Modern surface waters have 3.3-4.1 pH, 0.5-3% total dissolved solids (TDS) and are actively precipitating gypsum crystals. The gypsum crystals trap the acid saline water as fluid inclusions, providing a record of recent surface water characteristics. Salar Ignorado gypsum contains three distinct types of primary fluid inclusions, which result from growth of the gypsum from surface waters. Petrography and microthermometry were performed on 27 gypsum crystals from Salar Ignorado to gain an understanding of recent water chemistry of the salar. One 18.3-cm-long gypsum crystal, hosting primary fluid inclusions along 28 successive growth bands, was the focus for fluid inclusion studies and allowed a record of high-resolution chemical trends. This crystal showed a change in parent fluids during growth, from low salinity, to high salinity, back to low salinity. At the bottom of the crystal, the lowest six fluid inclusion assemblages have salinities of 1.7-5.1 eq. wt. % NaCl. The next nine fluid inclusion assemblages have significantly higher salinity (18.6-27.4 eq. wt. % NaCl) inclusions. The twelve fluid inclusion assemblages near the top of the crystal have low salinity (0.9-8.3 eq. wt. % NaCl) like those at the bottom of the crystal. The high-salinity fluid inclusions in the middle of this gypsum crystal are interpreted to have formed during a pulse of magmatic/hydrothermal fluids to the surface, perhaps during local active volcanism. Secondary evidence of a magmatic influence on surface waters includes hydrogen sulfide and high molecular weight solid hydrocarbons within some fluid inclusions. This study is among the first detailed fluid inclusion studies of gypsum and suggests that fluid inclusions in gypsum can be paleo-hydrogeologic proxies.
Geology, 2014
Could the abundant sulfate salts on Mars contain microfossils and/or viable microorganisms? Here ... more Could the abundant sulfate salts on Mars contain microfossils and/or viable microorganisms? Here we report a variety of microorganisms trapped both as solid inclusions and as potentially viable halophilic and acidophilic prokaryotes and eukaryotes within fl uid inclusions in Mars-analog gypsum. We have documented pennate diatoms, green algae, and prokaryotes in gypsum precipitated from acid (pH 1.8-4.6) saline (5%-28% total dissolved solids) waters at Salars Gorbea and Ignorado in an active volcanic terrain in the high Andes (4000+ m) of northern Chile. These salars are strikingly similar in geology and geochemistry to Mars. We propose that this discovery should serve as a model for fossilization of possible life on Mars and may inform methodologies used in future missions to Mars. Furthermore, the potential longterm viability of microorganisms within fl uid inclusions in gypsum suggests the possibility of a living, yet isolated and likely dormant, microbiological community on Mars today.
Could the abundant sulfate salts on Mars contain microfossils and/or viable microorganisms? Here ... more Could the abundant sulfate salts on Mars contain microfossils and/or viable microorganisms? Here we report a variety of microorganisms trapped both as solid inclusions and as potentially viable halophilic and acidophilic prokaryotes and eukaryotes within fl uid inclusions in Mars-analog gypsum. We have documented pennate diatoms, green algae, and prokaryotes in gypsum precipitated from acid (pH 1.8-4.6) saline (5%-28% total dissolved solids) waters at Salars Gorbea and Ignorado in an active volcanic terrain in the high Andes (4000+ m) of northern Chile. These salars are strikingly similar in geology and geochemistry to Mars. We propose that this discovery should serve as a model for fossilization of possible life on Mars and may inform methodologies used in future missions to Mars. Furthermore, the potential longterm viability of microorganisms within fl uid inclusions in gypsum suggests the possibility of a living, yet isolated and likely dormant, microbiological community on Mars today.
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Papers by Francis Karmanocky