Papers by Francis Karmanocky
Quaternary Science Reviews, Apr 1, 2015
Quaternary Science Reviews, 2015
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
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