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- Arctic (1)
- Biomarker (1)
- BrGDGT (1)
- Bridging earthquakes and mountain building (1)
- Cascadia (1)
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- Coupling (1)
- GPS (1)
- Intact polar lipid (1)
- Inversion of tectonics from topography (1)
- Lake sediment (1)
- New method coupling erosional and mechanical modeling (1)
- Paleoclimate (1)
- Quantification of fault slip-and moment accrual-rates (1)
- San Francisco Bay Area (1)
- Seismic hazards (1)
- Silicon Valley (1)
- Slow slip (1)
- Subduction (1)
Articles 1 - 7 of 7
Full-Text Articles in Physical Sciences and Mathematics
Microbial Ecology Of A Shallow Alkaline Hydrothermal Vent: Strýtan Hydrothermal Field, Eyjafördur, Northern Iceland, Katrina I. Twing, L. M. Ward, Zachery K. Kane, Alexa Sanders, Roy Edward Price, H. Lizethe Pendleton, Donato Giovannelli, William J. Brazelton, Shawn E. Mcglynn
Microbial Ecology Of A Shallow Alkaline Hydrothermal Vent: Strýtan Hydrothermal Field, Eyjafördur, Northern Iceland, Katrina I. Twing, L. M. Ward, Zachery K. Kane, Alexa Sanders, Roy Edward Price, H. Lizethe Pendleton, Donato Giovannelli, William J. Brazelton, Shawn E. Mcglynn
Geosciences: Faculty Publications
Strýtan Hydrothermal Field (SHF) is a submarine system located in Eyjafördur in northern Iceland composed of two main vents: Big Strýtan and Arnarnesstrýtan. The vents are shallow, ranging from 16 to 70 m water depth, and vent high pH (up to 10.2), moderate temperature (Tmax ∼70°C), anoxic, fresh fluids elevated in dissolved silica, with slightly elevated concentrations of hydrogen and methane. In contrast to other alkaline hydrothermal vents, SHF is unique because it is hosted in basalt and therefore the high pH is not created by serpentinization. While previous studies have assessed the geology and geochemistry of this site, the …
Mountain Rivers Reveal The Earthquake Hazard Of Geologic Faults In Silicon Valley, Felipe Aron, Samuel A. Johnstone, Andreas Mavrommatis, Robert Sare, Frantz Maerten, John P. Loveless, Curtis W. Baden, George E. Hilley
Mountain Rivers Reveal The Earthquake Hazard Of Geologic Faults In Silicon Valley, Felipe Aron, Samuel A. Johnstone, Andreas Mavrommatis, Robert Sare, Frantz Maerten, John P. Loveless, Curtis W. Baden, George E. Hilley
Geosciences: Faculty Publications
The 1989, Mw = 6.9 Loma Prieta earthquake resulted in tens of lives lost and cost California almost 3% of its gross domestic product. Despite widespread damage, the earthquake did not clearly rupture the surface, challenging the identification and characterization of these hidden hazards. Here, we show that they can be illuminated by inverting fluvial topography for slip-and moment accrual-rates—fundamental components in earthquake hazard assessments—along relief-generating geologic faults. We applied this technique to thrust faults bounding the mountains along the western side of Silicon Valley in the San Francisco Bay Area, and discovered that these structures may be capable of …
Intact Polar Brgdgts In Arctic Lake Catchments: Implications For Lipid Sources And Paleoclimate Applications, Jonathan H. Raberg, Edgart Flores, Sarah E. Crump, Greg De Wet, Nadia Dildar, Gifford H. Miller, Áslaug Geirsdóttir, Julio Sepúlveda
Intact Polar Brgdgts In Arctic Lake Catchments: Implications For Lipid Sources And Paleoclimate Applications, Jonathan H. Raberg, Edgart Flores, Sarah E. Crump, Greg De Wet, Nadia Dildar, Gifford H. Miller, Áslaug Geirsdóttir, Julio Sepúlveda
Geosciences: Faculty Publications
Paleotemperature histories derived from lake sediment archives provide valuable context for modern and future climate changes. Branched glycerol dialkyl glycerol tetraether (brGDGT) lipids are a valuable tool in such pursuits due to their empirical correlation with temperature and near ubiquity in nature. However, the relative contributions of terrestrial and lacustrine sources of brGDGTs to lake sediments is site-dependent and difficult to constrain. Here, we explored the potential for intact brGDGTs—the complete lipids with polar head groups (HGs) still attached—to provide insight into the sources of brGDGTs on the landscape and their contributions to the sedimentary record in a set of …
The Oldest Mineralized Bryozoan? A Possible Palaeostomate In The Lower Cambrian Of Nevada, Usa, Sara B. Pruss, Lexie Leeser, Emily F. Smith, Andrey Yu Zhuravlev, Paul D. Taylor
The Oldest Mineralized Bryozoan? A Possible Palaeostomate In The Lower Cambrian Of Nevada, Usa, Sara B. Pruss, Lexie Leeser, Emily F. Smith, Andrey Yu Zhuravlev, Paul D. Taylor
Geosciences: Faculty Publications
All skeletal marine invertebrate phyla appeared during the Cambrian explosion, except for Bryozoa with mineralized skeletons, which first appear in the Early Ordovician. However, the skeletal diversity of Early Ordovician bryozoans suggests a preceding interval of diversification. We report a possible earliest occurrence of palaeostomate bryozoans in limestones of the Cambrian Age 4 Harkless Formation, western United States. Following recent interpretations of the early Cambrian Protomelission as a soft-bodied bryozoan, our findings add to the evidence of early Cambrian roots for the Bryozoa. The Harkless fossils resemble some esthonioporate and cystoporate bryozoans, showing a radiating pattern of densely packed tubes …
Prolonged Drying Trend Coincident With The Demise Of Norse Settlement In Southern Greenland, Boyang Zhao, Isla S. Castañeda, Jeffrey M. Salacup, Elizabeth K. Thomas, William C. Daniels, Tobias Schneider, Gregory A. De Wet, Raymond S. Bradley
Prolonged Drying Trend Coincident With The Demise Of Norse Settlement In Southern Greenland, Boyang Zhao, Isla S. Castañeda, Jeffrey M. Salacup, Elizabeth K. Thomas, William C. Daniels, Tobias Schneider, Gregory A. De Wet, Raymond S. Bradley
Geosciences: Faculty Publications
Declining temperature has been thought to explain the abandonment of Norse settlements, southern Greenland, in the early 15th century, although limited paleoclimate evidence is available from the inner settlement region itself. Here, we reconstruct the temperature and hydroclimate history from lake sediments at a site adjacent to a former Norse farm. We find no substantial temperature changes during the settlement period but rather that the region experienced a persistent drying trend, which peaked in the 16th century. Drier climate would have notably reduced grass production, which was essential for livestock overwintering, and this drying trend is concurrent with a Norse …
The Role Of Slow Slip Events In The Cascadia Subduction Zone Earthquake Cycle, Juliette P. Saux, Elias G. Molitors Bergman, Eileen L. Evans, John P. Loveless
The Role Of Slow Slip Events In The Cascadia Subduction Zone Earthquake Cycle, Juliette P. Saux, Elias G. Molitors Bergman, Eileen L. Evans, John P. Loveless
Geosciences: Faculty Publications
Slow slip events (SSEs) detected on the Cascadia Subduction Zone interface at 30–50 km depth imply a release of accumulated strain. However, studies of interseismic deformation in Cascadia typically find coupling on the upper 30 km of the interface, which is generally accepted as defining the seismogenic zone. Estimates of coupling using net interseismic velocities (including SSE effects) and restricting coupling to the shallow interface may underestimate slip deficit accumulation at depths >30 km. Here, we detect reversals in GPS motion as indications of SSEs, then use SSE displacements to estimate cumulative slow slip from 2007 to 2021. We calculate …
Phototrophy And Carbon Fixation In Chlorobi Postdate The Rise Of Oxygen, L. M. Ward, Patrick M. Shih
Phototrophy And Carbon Fixation In Chlorobi Postdate The Rise Of Oxygen, L. M. Ward, Patrick M. Shih
Geosciences: Faculty Publications
While most productivity on the surface of the Earth today is fueled by oxygenic photosynthesis, for much of Earth history it is thought that anoxygenic photosynthesis—using compounds like ferrous iron or sulfide as electron donors—drove most global carbon fixation. Anoxygenic photosynthesis is still performed by diverse bacteria in niche environments today. Of these, the Chlorobi (formerly green sulfur bacteria) are often interpreted as being particularly ancient and are frequently proposed to have fueled the biosphere during late Archean and early Paleoproterozoic time before the rise of oxygenic photosynthesis. Here, we perform comparative genomic, phylogenetic, and molecular clock analyses to determine …