James Conrad
I study seafloor geology along the West Coast of the U.S. using various types of geophysical surveys to map the seafloor and image sub-seafloor strata. The purpose of this work is to help understand the hazards posed to coastal communities and infrastructure by offshore active faults and submarine landslides.
I received a Bachelors Degree in Earth Science from U.C. Berkeley in 1981, and a Masters Degree in Geology from San Jose State University in 1993. I have worked at the USGS since 1981, first in the Minerals Program, where I worked to assess the potential for undiscovered mineral deposits in the western U.S., and used Argon geochronology to date mineral deposits and related igneous rocks. In 1995, I joined the Pacific Coastal and Marine Science Center, where I study marine geologic hazards such as earthquakes on offshore faults and tsunamis generated by submarine landslides.
Science and Products
Filter Total Items: 23
Minisparker and chirp seismic-reflection data of field activity 2014-645-FA collected in the outer Santa Barbara Channel, California, between 2014-11-12 to 2014-11-25 (ver. 2.0, March 2020)
The U.S. Geological Survey (USGS) collected high-resolution multichannel sparker, minisparker and chirp seismic-reflection data in November 2014, from offshore Catalina and Santa Cruz basins. The survey was designed to image faults and folds associated with movement on the faults in offshore southern California, including the Catalina, Catalina Ridge, San Clemente, and San Diego Trough faults. Dat
Multibeam bathymetry and acoustic-backscatter data collected in 2016 in Catalina Basin, southern California and merged multibeam bathymetry datasets of the northern portion of the Southern California Continental Borderland
In February 2016 the University of Washington in cooperation with the U.S. Geological Survey, Pacific Coastal and Marine Science Center (USGS, PCMSC) collected multibeam bathymetry and acoustic-backscatter data in and near the Catalina Basin, southern California aboard the University of Washington's Research Vessel Thomas G. Thompson. Data was collected using a Kongsberg EM300 multibeam echosounde
Multichannel minisparker and chirp seismic-reflection data of field activity 2015-651-FA; Chatham Strait and Cross Sound, southeastern Alaska from 2015-08-03 to 2015-08-21
High-resolution multichannel minisparker and chirp seismic-reflection data were collected in August of 2015 to explore marine geologic hazards of inland waterways of southeastern Alaska. Sub-bottom profiles were acquired in the inland waters between Glacier Bay and Juneau, including Cross Sound and Chatham Strait. High-resolution seismic-reflection profiles were acquired to assess evidence for act
Chirp seismic-reflection data collected offshore of San Diego and Los Angeles Counties, southern California, from 2011-06-08 to 2011-06-22 (USGS field activity S-7-11-SC)
This dataset includes raw and processed, high-resolution seismic-reflection data collected in 2011 to collect information on active offshore faults. The survey area is offshore southern California between Long Beach and San Diego. The data were collected aboard the U.S. Geological Survey R/V Parke Snavely. The seismic-reflection data were acquired using an EdgeTech 512 subbottom profiler. Subbotto
Chirp seismic-reflection data collected between Oceanside and La Jolla, offshore of southern California, from 2010-06-01 to 2010-06-12 (USGS field activity S-12-10-SC)
This dataset includes raw and processed, high-resolution seismic-reflection data collected in 2010 to collect information on active offshore faults. The survey is area is offshore southern California between Oceanside and La Jolla. The data were collected aboard the U.S. Geological Survey R/V Parke Snavely. The seismic-reflection data were acquired using an EdgeTech 512 chirp subbottom profiler. S
Minisparker seismic-reflection data collected offshore of San Diego and Los Angeles Counties, southern California, from 2011-06-08 to 2011-06-22 (USGS field activity S-7-11-SC)
This dataset includes raw and processed, high-resolution seismic-reflection data collected in 2011 to collect information on active offshore faults. The survey area is offshore southern California between Long Beach and San Diego. The data were collected aboard the U.S. Geological Survey R/V Parke Snavely. The seismic-reflection data were acquired using a SIG 2mille minisparker and an Edgetech 512
Minisparker seismic-reflection data collected between Oceanside and La Jolla, offshore of southern California, from 2010-06-01 to 2010-06-12 (USGS field activity S-12-10-SC)
This dataset includes raw and processed, high-resolution seismic-reflection data collected in 2010 to collect information on active offshore faults. The survey area is offshore southern California between Oceanside and La Jolla. The data were collected aboard the U.S. Geological Survey R/V Parke Snavely. The seismic-reflection data were acquired using a SIG 2mille minisparker. Subbottom acoustic p
Minisparker seismic-reflection data collected between Huntington Beach and San Diego, offshore of southern California, from 2008-04-28 to 2008-05-05 (USGS field activity B-1-08-SC)
This dataset includes raw and processed, high-resolution seismic-reflection data collected in 2008 to collect information on active offshore faults. The survey area is offshore southern California between Huntington Beach and San Diego. The data were collected aboard the R/V Bold. The seismic-reflection data were acquired using a SIG 2mille minisparker. Subbottom acoustic penetration spanned tens
Chirp seismic-reflection data collected in the San Pedro Basin, offshore of southern California, from 2009-07-06 to 2009-07-10 (USGS field activity S-5-09-SC)
This dataset includes raw and processed, high-resolution seismic-reflection data collected in 2009 to explore a possible connection between the San Diego Trough Fault and the San Pedro Basin Fault. The survey is in the San Pedro Basin between Santa Catalina Island and San Pedro, California. The data were collected aboard the U.S. Geological Survey R/V Parke Snavely. The seismic-reflection data wer
Minisparker seismic-reflection data collected in the San Pedro Basin, offshore of southern California, from 2009-07-06 to 2009-07-10 (USGS field activity S-5-09-SC)
This dataset includes raw and processed, high-resolution seismic-reflection data collected in 2009 to explore a possible connection between the San Diego Trough Fault and the San Pedro Basin Fault. The survey is in the San Pedro Basin between Santa Catalina Island and San Pedro, California. The data were collected aboard the U.S. Geological Survey R/V Parke Snavely. The seismic-reflection data wer
Sediment core data from offshore Palos Verdes, California
The seven files included in this U.S. Geological Survey data release are data from a set of sediment cores acquired from the continental slope, offshore Los Angeles and the Palos Verdes Peninsula, adjacent to the Palos Verdes Fault. Gravity cores were collected by the USGS in 2009 (cruise ID S-I2-09-SC; http://cmgds.marine.usgs.gov/fan_info.php?fan=SI209SC), and vibracores were collected with the
Filter Total Items: 40
Slope failure and mass transport processes along the Queen Charlotte Fault Zone, western British Columbia
Multibeam echosounder (MBES) images, 3.5 kHz seismic-reflection profiles and piston cores obtained along the southern Queen Charlotte Fault Zone are used to map and date mass-wasting events at this transform margin – a seismically active boundary that separates the Pacific Plate from the North American Plate. Whereas the upper continental slope adjacent to and east (upslope) of the fault zone offs
Authors
H. G. Greene, J. Vaughn Barrie, Daniel S. Brothers, James E. Conrad, Kim Conway, Amy E. East, Randolph J. Enkin, Katherine L. Maier, Maureen A. L. Walton, K .M. M. Rohr
Slope failure and mass transport processes along the Queen Charlotte Fault, southeastern Alaska
The Queen Charlotte Fault defines the Pacific–North America transform plate boundary in western Canada and southeastern Alaska for c. 900 km. The entire length of the fault is submerged along a continental margin dominated by Quaternary glacial processes, yet the geomorphology along the margin has never been systematically examined due to the absence of high-resolution seafloor mapping data. Hence
Authors
Daniel Brothers, Brian D. Andrews, Maureen A. L. Walton, H. Gary Greene, J. Vaughn Barrie, Nathaniel C. Miller, Uri S. ten Brink, Amy E. East, Peter J. Haeussler, Jared W. Kluesner, James E. Conrad
Strain partitioning in southeastern Alaska: Is the Chatham Strait Fault active?
A 1200 km-long transform plate boundary passes through southeastern Alaska and northwestern British Columbia and represents one of the most seismically active, but poorly understood continental margins of North America. Although most of the plate motion is accommodated by the right-lateral Queen Charlotte–Fairweather Fault (QCFF) System, which has produced at least six M > 7 earthquakes since 1920
Authors
Daniel S. Brothers, Julie L. Elliott, James E. Conrad, Peter J. Haeussler, Jared W. Kluesner
The tectonically controlled San Gabriel Channel–Lobe Transition Zone, Catalina Basin, Southern California Borderland
High-resolution geophysical data across the Catalina Basin, offshore southern California, USA, reveal a complex channel–lobe transition zone (CLTZ) and provide an opportunity to characterize an entire seafloor CLTZ in a tectonically active and confined-basin setting. The seafloor morphology, distribution of depositional and erosional features, and location of depocenters in the CLTZ are controlled
Authors
Katherine L. Maier, Emily C. Roland, Maureen A. L. Walton, James E. Conrad, Daniel S. Brothers, Peter Dartnell, Jared W. Kluesner
Seafloor fluid seeps on Kimki Ridge, offshore southern California: Links to active strike-slip faulting
The Kimki Ridge fluid seeps are located in western Catalina Basin about 60 km southwest of the southern California mainland and at a water depth of approximately 1100 m. Multichannel seismic reflection profiles collected by the U.S. Geological Survey (USGS) in 2014 show acoustic transparency within the Kimki Ridge, suggesting the possibility of fluid seeps and possible sub-seafloor fluid pathways.
Authors
James E. Conrad, Nancy G. Prouty, Maureen A. L. Walton, Jared W. Kluesner, Katherine L. Maier, Mary McGann, Daniel S. Brothers, Emily C. Roland, Peter Dartnell
Records of continental slope sediment flow morphodynamic responses to gradient and active faulting from integrated AUV and ROV data, offshore Palos Verdes, southern California Borderland
Variations in seabed gradient are widely acknowledged to influence deep-water deposition, but are often difficult to measure in sufficient detail from both modern and ancient examples. On the continental slope offshore Los Angeles, California, autonomous underwater vehicle, remotely operated vehicle, and shipboard methods were used to collect a dense grid of high-resolution multibeam bathymetry, c
Authors
Katherine L. Maier, Daniel S. Brothers, Charles K. Paull, Mary McGann, David W. Caress, James E. Conrad
The Palos Verdes Fault offshore southern California: late Pleistocene to present tectonic geomorphology, seascape evolution and slip rate estimate based on AUV and ROV surveys
The Palos Verdes Fault (PVF) is one of few active faults in Southern California that crosses the shoreline and can be studied using both terrestrial and subaqueous methodologies. To characterize the near-seafloor fault morphology, tectonic influences on continental slope sedimentary processes and late Pleistocene to present slip rate, a grid of high-resolution multibeam bathymetric data, and chirp
Authors
Daniel S. Brothers, James E. Conrad, Katherine L. Maier, Charles K. Paull, Mary L. McGann, David W. Caress
Bathymetry and acoustic backscatter: outer mainland shelf and slope, Gulf of Santa Catalina, southern California
In 2010 and 2011, scientists from the U.S. Geological Survey (USGS), Coastal and Marine Geology Program, acquired bathymetry and acoustic-backscatter data from the outer shelf and slope region offshore of southern California. The surveys were conducted as part of the USGS Marine Geohazards Program. Assessment of the hazards posed by offshore faults, submarine landslides, and tsunamis are facilitat
Authors
Peter Dartnell, James E. Conrad, Holly F. Ryan, David P. Finlayson
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 geometry o
Authors
C. K. Paull, D.W. Caress, E. Lundsten, R. Gwiazda, K. Anderson, M. McGann, J. Conrad, B. Edwards, E.J. Sumner
Hyperpycnal plume-derived fans in the Santa Barbara Channel, California
Hyperpycnal gravity currents rapidly transport sediment across shore from rivers to the continental shelf and deep sea. Although these geophysical processes are important sediment dispersal mechanisms, few distinct geomorphic features on the continental shelf can be attributed to hyperpycnal flows. Here we provide evidence of large depositional features derived from hyperpycnal plumes on the conti
Authors
Jonathan A. Warrick, Alexander R. Simms, Andy Ritchie, Elisabeth Steel, Pete Dartnell, James E. Conrad, David P. Finlayson
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 a 5-km-wid
Authors
Holly F. Ryan, James E. Conrad, C. K. Paull, Mary McGann
Constraints on the development of Proterozoic basins in central India from 40Ar/39Ar analysis of authigenic glauconitic minerals
Ages of some key stratigraphic sequences in central Indian Proterozoic basins are based predominantly on lithostratigraphic relationships that have been constrained by only a few radioisotopic dates. To help improve age constraints, single grains of glauconitic minerals taken from sandstone and limestone in two Proterozoic sequences in the Pranhita-Godavari Valley and the Chattisgarh basin were an
Authors
J. E. Conrad, J. R. Hein, A.K. Chaudhuri, S. Patranabis-Deb, J. Mukhopadhyay, G.K. Deb, N.J. Beukes
Science and Products
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Filter Total Items: 23
Minisparker and chirp seismic-reflection data of field activity 2014-645-FA collected in the outer Santa Barbara Channel, California, between 2014-11-12 to 2014-11-25 (ver. 2.0, March 2020)
The U.S. Geological Survey (USGS) collected high-resolution multichannel sparker, minisparker and chirp seismic-reflection data in November 2014, from offshore Catalina and Santa Cruz basins. The survey was designed to image faults and folds associated with movement on the faults in offshore southern California, including the Catalina, Catalina Ridge, San Clemente, and San Diego Trough faults. DatMultibeam bathymetry and acoustic-backscatter data collected in 2016 in Catalina Basin, southern California and merged multibeam bathymetry datasets of the northern portion of the Southern California Continental Borderland
In February 2016 the University of Washington in cooperation with the U.S. Geological Survey, Pacific Coastal and Marine Science Center (USGS, PCMSC) collected multibeam bathymetry and acoustic-backscatter data in and near the Catalina Basin, southern California aboard the University of Washington's Research Vessel Thomas G. Thompson. Data was collected using a Kongsberg EM300 multibeam echosoundeMultichannel minisparker and chirp seismic-reflection data of field activity 2015-651-FA; Chatham Strait and Cross Sound, southeastern Alaska from 2015-08-03 to 2015-08-21
High-resolution multichannel minisparker and chirp seismic-reflection data were collected in August of 2015 to explore marine geologic hazards of inland waterways of southeastern Alaska. Sub-bottom profiles were acquired in the inland waters between Glacier Bay and Juneau, including Cross Sound and Chatham Strait. High-resolution seismic-reflection profiles were acquired to assess evidence for actChirp seismic-reflection data collected offshore of San Diego and Los Angeles Counties, southern California, from 2011-06-08 to 2011-06-22 (USGS field activity S-7-11-SC)
This dataset includes raw and processed, high-resolution seismic-reflection data collected in 2011 to collect information on active offshore faults. The survey area is offshore southern California between Long Beach and San Diego. The data were collected aboard the U.S. Geological Survey R/V Parke Snavely. The seismic-reflection data were acquired using an EdgeTech 512 subbottom profiler. SubbottoChirp seismic-reflection data collected between Oceanside and La Jolla, offshore of southern California, from 2010-06-01 to 2010-06-12 (USGS field activity S-12-10-SC)
This dataset includes raw and processed, high-resolution seismic-reflection data collected in 2010 to collect information on active offshore faults. The survey is area is offshore southern California between Oceanside and La Jolla. The data were collected aboard the U.S. Geological Survey R/V Parke Snavely. The seismic-reflection data were acquired using an EdgeTech 512 chirp subbottom profiler. SMinisparker seismic-reflection data collected offshore of San Diego and Los Angeles Counties, southern California, from 2011-06-08 to 2011-06-22 (USGS field activity S-7-11-SC)
This dataset includes raw and processed, high-resolution seismic-reflection data collected in 2011 to collect information on active offshore faults. The survey area is offshore southern California between Long Beach and San Diego. The data were collected aboard the U.S. Geological Survey R/V Parke Snavely. The seismic-reflection data were acquired using a SIG 2mille minisparker and an Edgetech 512Minisparker seismic-reflection data collected between Oceanside and La Jolla, offshore of southern California, from 2010-06-01 to 2010-06-12 (USGS field activity S-12-10-SC)
This dataset includes raw and processed, high-resolution seismic-reflection data collected in 2010 to collect information on active offshore faults. The survey area is offshore southern California between Oceanside and La Jolla. The data were collected aboard the U.S. Geological Survey R/V Parke Snavely. The seismic-reflection data were acquired using a SIG 2mille minisparker. Subbottom acoustic pMinisparker seismic-reflection data collected between Huntington Beach and San Diego, offshore of southern California, from 2008-04-28 to 2008-05-05 (USGS field activity B-1-08-SC)
This dataset includes raw and processed, high-resolution seismic-reflection data collected in 2008 to collect information on active offshore faults. The survey area is offshore southern California between Huntington Beach and San Diego. The data were collected aboard the R/V Bold. The seismic-reflection data were acquired using a SIG 2mille minisparker. Subbottom acoustic penetration spanned tensChirp seismic-reflection data collected in the San Pedro Basin, offshore of southern California, from 2009-07-06 to 2009-07-10 (USGS field activity S-5-09-SC)
This dataset includes raw and processed, high-resolution seismic-reflection data collected in 2009 to explore a possible connection between the San Diego Trough Fault and the San Pedro Basin Fault. The survey is in the San Pedro Basin between Santa Catalina Island and San Pedro, California. The data were collected aboard the U.S. Geological Survey R/V Parke Snavely. The seismic-reflection data werMinisparker seismic-reflection data collected in the San Pedro Basin, offshore of southern California, from 2009-07-06 to 2009-07-10 (USGS field activity S-5-09-SC)
This dataset includes raw and processed, high-resolution seismic-reflection data collected in 2009 to explore a possible connection between the San Diego Trough Fault and the San Pedro Basin Fault. The survey is in the San Pedro Basin between Santa Catalina Island and San Pedro, California. The data were collected aboard the U.S. Geological Survey R/V Parke Snavely. The seismic-reflection data werSediment core data from offshore Palos Verdes, California
The seven files included in this U.S. Geological Survey data release are data from a set of sediment cores acquired from the continental slope, offshore Los Angeles and the Palos Verdes Peninsula, adjacent to the Palos Verdes Fault. Gravity cores were collected by the USGS in 2009 (cruise ID S-I2-09-SC; http://cmgds.marine.usgs.gov/fan_info.php?fan=SI209SC), and vibracores were collected with the - Maps
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Filter Total Items: 40
Slope failure and mass transport processes along the Queen Charlotte Fault Zone, western British Columbia
Multibeam echosounder (MBES) images, 3.5 kHz seismic-reflection profiles and piston cores obtained along the southern Queen Charlotte Fault Zone are used to map and date mass-wasting events at this transform margin – a seismically active boundary that separates the Pacific Plate from the North American Plate. Whereas the upper continental slope adjacent to and east (upslope) of the fault zone offs
AuthorsH. G. Greene, J. Vaughn Barrie, Daniel S. Brothers, James E. Conrad, Kim Conway, Amy E. East, Randolph J. Enkin, Katherine L. Maier, Maureen A. L. Walton, K .M. M. RohrSlope failure and mass transport processes along the Queen Charlotte Fault, southeastern Alaska
The Queen Charlotte Fault defines the Pacific–North America transform plate boundary in western Canada and southeastern Alaska for c. 900 km. The entire length of the fault is submerged along a continental margin dominated by Quaternary glacial processes, yet the geomorphology along the margin has never been systematically examined due to the absence of high-resolution seafloor mapping data. Hence
AuthorsDaniel Brothers, Brian D. Andrews, Maureen A. L. Walton, H. Gary Greene, J. Vaughn Barrie, Nathaniel C. Miller, Uri S. ten Brink, Amy E. East, Peter J. Haeussler, Jared W. Kluesner, James E. ConradStrain partitioning in southeastern Alaska: Is the Chatham Strait Fault active?
A 1200 km-long transform plate boundary passes through southeastern Alaska and northwestern British Columbia and represents one of the most seismically active, but poorly understood continental margins of North America. Although most of the plate motion is accommodated by the right-lateral Queen Charlotte–Fairweather Fault (QCFF) System, which has produced at least six M > 7 earthquakes since 1920AuthorsDaniel S. Brothers, Julie L. Elliott, James E. Conrad, Peter J. Haeussler, Jared W. KluesnerThe tectonically controlled San Gabriel Channel–Lobe Transition Zone, Catalina Basin, Southern California Borderland
High-resolution geophysical data across the Catalina Basin, offshore southern California, USA, reveal a complex channel–lobe transition zone (CLTZ) and provide an opportunity to characterize an entire seafloor CLTZ in a tectonically active and confined-basin setting. The seafloor morphology, distribution of depositional and erosional features, and location of depocenters in the CLTZ are controlledAuthorsKatherine L. Maier, Emily C. Roland, Maureen A. L. Walton, James E. Conrad, Daniel S. Brothers, Peter Dartnell, Jared W. KluesnerSeafloor fluid seeps on Kimki Ridge, offshore southern California: Links to active strike-slip faulting
The Kimki Ridge fluid seeps are located in western Catalina Basin about 60 km southwest of the southern California mainland and at a water depth of approximately 1100 m. Multichannel seismic reflection profiles collected by the U.S. Geological Survey (USGS) in 2014 show acoustic transparency within the Kimki Ridge, suggesting the possibility of fluid seeps and possible sub-seafloor fluid pathways.AuthorsJames E. Conrad, Nancy G. Prouty, Maureen A. L. Walton, Jared W. Kluesner, Katherine L. Maier, Mary McGann, Daniel S. Brothers, Emily C. Roland, Peter DartnellRecords of continental slope sediment flow morphodynamic responses to gradient and active faulting from integrated AUV and ROV data, offshore Palos Verdes, southern California Borderland
Variations in seabed gradient are widely acknowledged to influence deep-water deposition, but are often difficult to measure in sufficient detail from both modern and ancient examples. On the continental slope offshore Los Angeles, California, autonomous underwater vehicle, remotely operated vehicle, and shipboard methods were used to collect a dense grid of high-resolution multibeam bathymetry, cAuthorsKatherine L. Maier, Daniel S. Brothers, Charles K. Paull, Mary McGann, David W. Caress, James E. ConradThe Palos Verdes Fault offshore southern California: late Pleistocene to present tectonic geomorphology, seascape evolution and slip rate estimate based on AUV and ROV surveys
The Palos Verdes Fault (PVF) is one of few active faults in Southern California that crosses the shoreline and can be studied using both terrestrial and subaqueous methodologies. To characterize the near-seafloor fault morphology, tectonic influences on continental slope sedimentary processes and late Pleistocene to present slip rate, a grid of high-resolution multibeam bathymetric data, and chirpAuthorsDaniel S. Brothers, James E. Conrad, Katherine L. Maier, Charles K. Paull, Mary L. McGann, David W. CaressBathymetry and acoustic backscatter: outer mainland shelf and slope, Gulf of Santa Catalina, southern California
In 2010 and 2011, scientists from the U.S. Geological Survey (USGS), Coastal and Marine Geology Program, acquired bathymetry and acoustic-backscatter data from the outer shelf and slope region offshore of southern California. The surveys were conducted as part of the USGS Marine Geohazards Program. Assessment of the hazards posed by offshore faults, submarine landslides, and tsunamis are facilitatAuthorsPeter Dartnell, James E. Conrad, Holly F. Ryan, David P. FinlaysonAnatomy 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 geometry oAuthorsC. K. Paull, D.W. Caress, E. Lundsten, R. Gwiazda, K. Anderson, M. McGann, J. Conrad, B. Edwards, E.J. SumnerHyperpycnal plume-derived fans in the Santa Barbara Channel, California
Hyperpycnal gravity currents rapidly transport sediment across shore from rivers to the continental shelf and deep sea. Although these geophysical processes are important sediment dispersal mechanisms, few distinct geomorphic features on the continental shelf can be attributed to hyperpycnal flows. Here we provide evidence of large depositional features derived from hyperpycnal plumes on the contiAuthorsJonathan A. Warrick, Alexander R. Simms, Andy Ritchie, Elisabeth Steel, Pete Dartnell, James E. Conrad, David P. FinlaysonSlip 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 a 5-km-widAuthorsHolly F. Ryan, James E. Conrad, C. K. Paull, Mary McGannConstraints on the development of Proterozoic basins in central India from 40Ar/39Ar analysis of authigenic glauconitic minerals
Ages of some key stratigraphic sequences in central Indian Proterozoic basins are based predominantly on lithostratigraphic relationships that have been constrained by only a few radioisotopic dates. To help improve age constraints, single grains of glauconitic minerals taken from sandstone and limestone in two Proterozoic sequences in the Pranhita-Godavari Valley and the Chattisgarh basin were anAuthorsJ. E. Conrad, J. R. Hein, A.K. Chaudhuri, S. Patranabis-Deb, J. Mukhopadhyay, G.K. Deb, N.J. Beukes - News