Mary McGann (Former Employee)
Science and Products
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Filter Total Items: 75
Seafloor geomorphic manifestations of gas venting and shallow subbottom gas hydrate occurrences Seafloor geomorphic manifestations of gas venting and shallow subbottom gas hydrate occurrences
High-resolution multibeam bathymetry data collected with an autonomous underwater vehicle (AUV) complemented by compressed high-intensity radar pulse (Chirp) profiles and remotely operated vehicle (ROV) observations and sediment sampling reveal a distinctive rough topography associated with seafloor gas venting and/or near-subsurface gas hydrate accumulations. The surveys provide 1 m...
Authors
C. Paull, D. Caress, Hans Thomas, Eve Lundsten, Kayce Anderson, Roberto Gwiazda, M Riedel, Mary McGann, J C Herguera
Earliest record of the invasive Foraminifera Trochammina hadai in San Francisco Bay, California, USA Earliest record of the invasive Foraminifera Trochammina hadai in San Francisco Bay, California, USA
In 1995, Trochammina hadai, a benthic Foraminifera prevalent in Japanese estuaries, was found in San Francisco Bay, California, USA. Subsequent field investigations determined that the species was also present in nearly all of the major ports and estuaries along the western United States. Because of its widespread colonization, it is of interest to determine when T. hadai first appeared...
Authors
Mary McGann
Sub-decadal turbidite frequency during the early Holocene: Eel Fan, offshore northern California 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 Paull, Mary L. McGann, Esther J. Sumner, Philip Barnes, Eve Lundsten, Krystle Anderson, Roberto Gwiazda, Brian Edwards, David W Caress
The search for geologic evidence of distant-source tsunamis using new field data in California The search for geologic evidence of distant-source tsunamis using new field data in California
A statewide assessment for geological evidence of tsunamis, primarily from distant-source events, found tsunami deposits at several locations, though evidence was absent at most locations evaluated. Several historical distant-source tsunamis, including the 1946 Aleutian, 1960 Chile, and 1964 Alaska events, caused inundation along portions of the northern and central California coast...
Authors
Rick Wilson, Eileen Hemphill-Haley, Bruce Jaffe, Bruce Richmond, Robert Peters, Nick Graehl, Harvey Kelsey, Robert Leeper, Steve Watt, Mary McGann, Don Hoirup, Catherine Chague-Goff, James Goff, Dylan Caldwell, Casey Loofbourrow
Late 20th Century benthic foraminiferal distribution in Central San Francisco Bay, California: Influence of the Trochammina hadai invasion 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 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 Clague, Brian Dreyer, Jennifer Paduan, Julie Martin, David W Caress, James Gillespie, Deborah Kelley, Hans Thomas, Ryan Portner, John R. Delaney, Thomas Guilderson, Mary L. McGann
Heavy mineral analysis for assessing the provenance of sandy sediment in the San Francisco Bay Coastal System 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 Wong, Donald L. Woodrow, Mary McGann
The timing of sediment transport down Monterey Submarine Canyon, offshore California 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 Paull, William Ussler, Mary McGann, Jan-Pieter Buylaert, Eve Lundsten
Geologic history of the summit of Axial Seamount, Juan de Fuca Ridge 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 Clague, Brian Dreyer, Jennifer Paduan, Julie Martin, William Chadwick, David W Caress, Ryan Portner, Thomas Guilderson, Mary McGann, Hans Thomas, David Butterfield, Robert Embley
Anatomy of La Jolla submarine canyon system; offshore southern California 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. 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 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 Foxgrover, Edwin Elias, Li H. Erikson, James Hein, Mary McGann, Kira Mizell, Robert Rosenbauer, Peter Swarzenski, Renee Takesue, Florence Wong, Don Woodrow
The FOBIMO (FOraminiferal BIo-MOnitoring) initiative—Towards a standardised protocol for soft-bottom benthic foraminiferal monitoring studies 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
Science and Products
Filter Total Items: 15
No Result Found
Filter Total Items: 75
Seafloor geomorphic manifestations of gas venting and shallow subbottom gas hydrate occurrences Seafloor geomorphic manifestations of gas venting and shallow subbottom gas hydrate occurrences
High-resolution multibeam bathymetry data collected with an autonomous underwater vehicle (AUV) complemented by compressed high-intensity radar pulse (Chirp) profiles and remotely operated vehicle (ROV) observations and sediment sampling reveal a distinctive rough topography associated with seafloor gas venting and/or near-subsurface gas hydrate accumulations. The surveys provide 1 m...
Authors
C. Paull, D. Caress, Hans Thomas, Eve Lundsten, Kayce Anderson, Roberto Gwiazda, M Riedel, Mary McGann, J C Herguera
Earliest record of the invasive Foraminifera Trochammina hadai in San Francisco Bay, California, USA Earliest record of the invasive Foraminifera Trochammina hadai in San Francisco Bay, California, USA
In 1995, Trochammina hadai, a benthic Foraminifera prevalent in Japanese estuaries, was found in San Francisco Bay, California, USA. Subsequent field investigations determined that the species was also present in nearly all of the major ports and estuaries along the western United States. Because of its widespread colonization, it is of interest to determine when T. hadai first appeared...
Authors
Mary McGann
Sub-decadal turbidite frequency during the early Holocene: Eel Fan, offshore northern California 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 Paull, Mary L. McGann, Esther J. Sumner, Philip Barnes, Eve Lundsten, Krystle Anderson, Roberto Gwiazda, Brian Edwards, David W Caress
The search for geologic evidence of distant-source tsunamis using new field data in California The search for geologic evidence of distant-source tsunamis using new field data in California
A statewide assessment for geological evidence of tsunamis, primarily from distant-source events, found tsunami deposits at several locations, though evidence was absent at most locations evaluated. Several historical distant-source tsunamis, including the 1946 Aleutian, 1960 Chile, and 1964 Alaska events, caused inundation along portions of the northern and central California coast...
Authors
Rick Wilson, Eileen Hemphill-Haley, Bruce Jaffe, Bruce Richmond, Robert Peters, Nick Graehl, Harvey Kelsey, Robert Leeper, Steve Watt, Mary McGann, Don Hoirup, Catherine Chague-Goff, James Goff, Dylan Caldwell, Casey Loofbourrow
Late 20th Century benthic foraminiferal distribution in Central San Francisco Bay, California: Influence of the Trochammina hadai invasion 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 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 Clague, Brian Dreyer, Jennifer Paduan, Julie Martin, David W Caress, James Gillespie, Deborah Kelley, Hans Thomas, Ryan Portner, John R. Delaney, Thomas Guilderson, Mary L. McGann
Heavy mineral analysis for assessing the provenance of sandy sediment in the San Francisco Bay Coastal System 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 Wong, Donald L. Woodrow, Mary McGann
The timing of sediment transport down Monterey Submarine Canyon, offshore California 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 Paull, William Ussler, Mary McGann, Jan-Pieter Buylaert, Eve Lundsten
Geologic history of the summit of Axial Seamount, Juan de Fuca Ridge 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 Clague, Brian Dreyer, Jennifer Paduan, Julie Martin, William Chadwick, David W Caress, Ryan Portner, Thomas Guilderson, Mary McGann, Hans Thomas, David Butterfield, Robert Embley
Anatomy of La Jolla submarine canyon system; offshore southern California 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. 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 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 Foxgrover, Edwin Elias, Li H. Erikson, James Hein, Mary McGann, Kira Mizell, Robert Rosenbauer, Peter Swarzenski, Renee Takesue, Florence Wong, Don Woodrow
The FOBIMO (FOraminiferal BIo-MOnitoring) initiative—Towards a standardised protocol for soft-bottom benthic foraminiferal monitoring studies 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