Mary McGann
Research Geologist at the USGS Pacific Coastal and Marine Science Center
Science and Products
Filter Total Items: 14
No Result Found
Filter Total Items: 67
Sub-decadal turbidite frequency during the early Holocene: Eel Fan, offshore northern California
Remotely operated and autonomous underwater vehicle technologies were used to image and sample exceptional deep sea outcrops where an ∼100-m-thick section of turbidite beds is exposed on the headwalls of two giant submarine scours on Eel submarine fan, offshore northern California (USA). These outcrops provide a rare opportunity to connect young deep-sea turbidites with their feeder...
Authors
Charles K. Paull, Mary L. McGann, Esther J. Sumner, Philip M Barnes, Eve M. Lundsten, Krystle Anderson, Roberto Gwiazda, Brian D. Edwards, David W Caress
Late 20th Century benthic foraminiferal distribution in Central San Francisco Bay, California: Influence of the Trochammina hadai invasion
The distribution of foraminifera in most of San Francisco Bay is well documented, but this is not the case for the subembayment known as Central Bay. To resolve this, 55 grab samples obtained in 1998 were analyzed to characterize the foraminiferal fauna in the surface sediments of the area. Thirty-five species were identified, including the invasive Japanese species Trochammina hadai...
Authors
Mary L. McGann
Eruptive and tectonic history of the Endeavour Segment, Juan de Fuca Ridge, based on AUV mapping data and lava flow ages
High-resolution bathymetric surveys from autonomous underwater vehicles ABE and D. Allan B. were merged to create a coregistered map of 71.7 km2 of the Endeavour Segment of the Juan de Fuca Ridge. Radiocarbon dating of foraminifera in cores from three dives of remotely operated vehicle Doc Ricketts provide minimum eruption ages for 40 lava flows that are combined with the bathymetric...
Authors
David A. Clague, Brian M Dreyer, Jennifer B. Paduan, Julie F Martin, David W Caress, James B. Gillespie, Deborah S Kelley, Hans Thomas, Ryan A Portner, John R. Delaney, Thomas P. Guilderson, Mary L. McGann
Heavy mineral analysis for assessing the provenance of sandy sediment in the San Francisco Bay Coastal System
Heavy or high-specific gravity minerals make up a small but diagnostic component of sediment that is well suited for determining the provenance and distribution of sediment transported through estuarine and coastal systems worldwide. By this means, we see that surficial sand-sized sediment in the San Francisco Bay Coastal System comes primarily from the Sierra Nevada and associated...
Authors
Florence L. Wong, Donald L. Woodrow, Mary McGann
The timing of sediment transport down Monterey Submarine Canyon, offshore California
While submarine canyons are the major conduits through which sediments are transported from the continents out into the deep sea, the time it takes for sediment to pass down through a submarine canyon system is poorly constrained. Here we report on the first study to couple optically stimulated luminescence (OSL) ages of quartz sand deposits and accelerator mass spectrometry 14C ages...
Authors
Thomas Stevens, Charles K. Paull, William III Ussler, Mary McGann, Jan-Pieter Buylaert, Eve M. Lundsten
Geologic history of the summit of Axial Seamount, Juan de Fuca Ridge
Multibeam (1 m resolution) and side scan data collected from an autonomous underwater vehicle, and lava samples, radiocarbon-dated sediment cores, and observations of flow contacts collected by remotely operated vehicle were combined to reconstruct the geologic history and flow emplacement processes on Axial Seamount's summit and upper rift zones. The maps show 52 post-410 CE lava flows...
Authors
David A. Clague, Brian M Dreyer, Jennifer B. Paduan, Julie F Martin, William W Jr Chadwick, David W Caress, Ryan A Portner, Thomas P. Guilderson, Mary McGann, Hans Thomas, David A Butterfield, Robert W Embley
Anatomy of La Jolla submarine canyon system; offshore southern California
An autonomous underwater vehicle (AUV) carrying a multibeam sonar and a chirp profiler was used to map sections of the seafloor within the La Jolla Canyon, offshore southern California, at sub-meter scales. Close-up observations and sampling were conducted during remotely operated vehicle (ROV) dives. Minisparker seismic-reflection profiles from a surface ship help to define the overall...
Authors
C. K. Paull, D.W. Caress, E. Lundsten, R. Gwiazda, K. Anderson, M. McGann, J. Conrad, B. Edwards, E.J. Sumner
Integration of bed characteristics, geochemical tracers, current measurements, and numerical modeling for assessing the provenance of beach sand in the San Francisco Bay Coastal System
Over 150 million m3 of sand-sized sediment has disappeared from the central region of the San Francisco Bay Coastal System during the last half century. This enormous loss may reflect numerous anthropogenic influences, such as watershed damming, bay-fill development, aggregate mining, and dredging. The reduction in Bay sediment also appears to be linked to a reduction in sediment supply...
Authors
Patrick L. Barnard, Amy C. Foxgrover, Edwin P.L. Elias, Li H. Erikson, James R. Hein, Mary McGann, Kira Mizell, Robert J. Rosenbauer, Peter W. Swarzenski, Renee K. Takesue, Florence L. Wong, Don Woodrow
Arrival and expansion of the invasive foraminifera Trochammina hadai Uchio in Padilla Bay, Washington
Trochammina hadai Uchio, a benthic foraminifera native to Japanese estuaries, was first identified as an invasive in 1995 in San Francisco Bay and later in 16 other west coast estuaries. To investigate the timing of the arrival and expansion of this invasive species in Padilla Bay, Washington, we analyzed the distribution of foraminifera in two surface samples collected in 1971, in nine...
Authors
Mary McGann, Eric E. Grossman, Renee K. Takesue, Dan Penttila, John P. Walsh, Reide Corbett
The FOBIMO (FOraminiferal BIo-MOnitoring) initiative—Towards a standardised protocol for soft-bottom benthic foraminiferal monitoring studies
The European Community Marine Strategy Framework Directive (MSFD) was established to provide guidelines for monitoring the quality of marine ecosystems. Monitoring the status of marine environments is traditionally based on macrofauna surveys, for which standardised methods have been established. Benthic foraminifera are also good indicators of environmental status because of their fast...
Authors
Joachim Schoenfeld, Elisabeth Alve, Emmanuelle Geslin, Frans Jorissen, Sergei Korsun, Silva Spezzaferri, Sigal Abramovich, Ahuva Almogi-Labin, Eric Armynot du Chatelet, Christine Barras, Luisa Bergamin, Erica Bicchi, Vincent Bouchet, Alejandro Cearreta, Letizia Di Bella, Noortje Dijkstra, Sibelle Trevisan Disaro, Luciana Ferraro, Fabrizio Frontalini, Giordana Gennari, Elena Golikova, Kristin Haynert, Silvia Hess, Katrine Husum, Virginia Martins, Mary McGann, Shai Oron, Elena Romano, Silvia Mello Sousa, Akira Tsujimoto
Slip rate on the San Diego trough fault zone, inner California Borderland, and the 1986 Oceanside earthquake swarm revisited
The San Diego trough fault zone (SDTFZ) is part of a 90-km-wide zone of faults within the inner California Borderland that accommodates motion between the Pacific and North American plates. Along with most faults offshore southern California, the slip rate and paleoseismic history of the SDTFZ are unknown. We present new seismic reflection data that show that the fault zone steps across...
Authors
Holly F. Ryan, James E. Conrad, C. K. Paull, Mary McGann
Paleoceanograpic changes on the Farallon Escarpment off central California during the last 16,000 years
No abstract available.
Authors
Mary McGann
Science and Products
Filter Total Items: 14
No Result Found
Filter Total Items: 67
Sub-decadal turbidite frequency during the early Holocene: Eel Fan, offshore northern California
Remotely operated and autonomous underwater vehicle technologies were used to image and sample exceptional deep sea outcrops where an ∼100-m-thick section of turbidite beds is exposed on the headwalls of two giant submarine scours on Eel submarine fan, offshore northern California (USA). These outcrops provide a rare opportunity to connect young deep-sea turbidites with their feeder...
Authors
Charles K. Paull, Mary L. McGann, Esther J. Sumner, Philip M Barnes, Eve M. Lundsten, Krystle Anderson, Roberto Gwiazda, Brian D. Edwards, David W Caress
Late 20th Century benthic foraminiferal distribution in Central San Francisco Bay, California: Influence of the Trochammina hadai invasion
The distribution of foraminifera in most of San Francisco Bay is well documented, but this is not the case for the subembayment known as Central Bay. To resolve this, 55 grab samples obtained in 1998 were analyzed to characterize the foraminiferal fauna in the surface sediments of the area. Thirty-five species were identified, including the invasive Japanese species Trochammina hadai...
Authors
Mary L. McGann
Eruptive and tectonic history of the Endeavour Segment, Juan de Fuca Ridge, based on AUV mapping data and lava flow ages
High-resolution bathymetric surveys from autonomous underwater vehicles ABE and D. Allan B. were merged to create a coregistered map of 71.7 km2 of the Endeavour Segment of the Juan de Fuca Ridge. Radiocarbon dating of foraminifera in cores from three dives of remotely operated vehicle Doc Ricketts provide minimum eruption ages for 40 lava flows that are combined with the bathymetric...
Authors
David A. Clague, Brian M Dreyer, Jennifer B. Paduan, Julie F Martin, David W Caress, James B. Gillespie, Deborah S Kelley, Hans Thomas, Ryan A Portner, John R. Delaney, Thomas P. Guilderson, Mary L. McGann
Heavy mineral analysis for assessing the provenance of sandy sediment in the San Francisco Bay Coastal System
Heavy or high-specific gravity minerals make up a small but diagnostic component of sediment that is well suited for determining the provenance and distribution of sediment transported through estuarine and coastal systems worldwide. By this means, we see that surficial sand-sized sediment in the San Francisco Bay Coastal System comes primarily from the Sierra Nevada and associated...
Authors
Florence L. Wong, Donald L. Woodrow, Mary McGann
The timing of sediment transport down Monterey Submarine Canyon, offshore California
While submarine canyons are the major conduits through which sediments are transported from the continents out into the deep sea, the time it takes for sediment to pass down through a submarine canyon system is poorly constrained. Here we report on the first study to couple optically stimulated luminescence (OSL) ages of quartz sand deposits and accelerator mass spectrometry 14C ages...
Authors
Thomas Stevens, Charles K. Paull, William III Ussler, Mary McGann, Jan-Pieter Buylaert, Eve M. Lundsten
Geologic history of the summit of Axial Seamount, Juan de Fuca Ridge
Multibeam (1 m resolution) and side scan data collected from an autonomous underwater vehicle, and lava samples, radiocarbon-dated sediment cores, and observations of flow contacts collected by remotely operated vehicle were combined to reconstruct the geologic history and flow emplacement processes on Axial Seamount's summit and upper rift zones. The maps show 52 post-410 CE lava flows...
Authors
David A. Clague, Brian M Dreyer, Jennifer B. Paduan, Julie F Martin, William W Jr Chadwick, David W Caress, Ryan A Portner, Thomas P. Guilderson, Mary McGann, Hans Thomas, David A Butterfield, Robert W Embley
Anatomy of La Jolla submarine canyon system; offshore southern California
An autonomous underwater vehicle (AUV) carrying a multibeam sonar and a chirp profiler was used to map sections of the seafloor within the La Jolla Canyon, offshore southern California, at sub-meter scales. Close-up observations and sampling were conducted during remotely operated vehicle (ROV) dives. Minisparker seismic-reflection profiles from a surface ship help to define the overall...
Authors
C. K. Paull, D.W. Caress, E. Lundsten, R. Gwiazda, K. Anderson, M. McGann, J. Conrad, B. Edwards, E.J. Sumner
Integration of bed characteristics, geochemical tracers, current measurements, and numerical modeling for assessing the provenance of beach sand in the San Francisco Bay Coastal System
Over 150 million m3 of sand-sized sediment has disappeared from the central region of the San Francisco Bay Coastal System during the last half century. This enormous loss may reflect numerous anthropogenic influences, such as watershed damming, bay-fill development, aggregate mining, and dredging. The reduction in Bay sediment also appears to be linked to a reduction in sediment supply...
Authors
Patrick L. Barnard, Amy C. Foxgrover, Edwin P.L. Elias, Li H. Erikson, James R. Hein, Mary McGann, Kira Mizell, Robert J. Rosenbauer, Peter W. Swarzenski, Renee K. Takesue, Florence L. Wong, Don Woodrow
Arrival and expansion of the invasive foraminifera Trochammina hadai Uchio in Padilla Bay, Washington
Trochammina hadai Uchio, a benthic foraminifera native to Japanese estuaries, was first identified as an invasive in 1995 in San Francisco Bay and later in 16 other west coast estuaries. To investigate the timing of the arrival and expansion of this invasive species in Padilla Bay, Washington, we analyzed the distribution of foraminifera in two surface samples collected in 1971, in nine...
Authors
Mary McGann, Eric E. Grossman, Renee K. Takesue, Dan Penttila, John P. Walsh, Reide Corbett
The FOBIMO (FOraminiferal BIo-MOnitoring) initiative—Towards a standardised protocol for soft-bottom benthic foraminiferal monitoring studies
The European Community Marine Strategy Framework Directive (MSFD) was established to provide guidelines for monitoring the quality of marine ecosystems. Monitoring the status of marine environments is traditionally based on macrofauna surveys, for which standardised methods have been established. Benthic foraminifera are also good indicators of environmental status because of their fast...
Authors
Joachim Schoenfeld, Elisabeth Alve, Emmanuelle Geslin, Frans Jorissen, Sergei Korsun, Silva Spezzaferri, Sigal Abramovich, Ahuva Almogi-Labin, Eric Armynot du Chatelet, Christine Barras, Luisa Bergamin, Erica Bicchi, Vincent Bouchet, Alejandro Cearreta, Letizia Di Bella, Noortje Dijkstra, Sibelle Trevisan Disaro, Luciana Ferraro, Fabrizio Frontalini, Giordana Gennari, Elena Golikova, Kristin Haynert, Silvia Hess, Katrine Husum, Virginia Martins, Mary McGann, Shai Oron, Elena Romano, Silvia Mello Sousa, Akira Tsujimoto
Slip rate on the San Diego trough fault zone, inner California Borderland, and the 1986 Oceanside earthquake swarm revisited
The San Diego trough fault zone (SDTFZ) is part of a 90-km-wide zone of faults within the inner California Borderland that accommodates motion between the Pacific and North American plates. Along with most faults offshore southern California, the slip rate and paleoseismic history of the SDTFZ are unknown. We present new seismic reflection data that show that the fault zone steps across...
Authors
Holly F. Ryan, James E. Conrad, C. K. Paull, Mary McGann
Paleoceanograpic changes on the Farallon Escarpment off central California during the last 16,000 years
No abstract available.
Authors
Mary McGann