Junbong Jang
William F. Waite
Laura A. Stern
Joo Yong Lee
20220630
Dataset of diatom controls on the sedimentation behavior of fine-grained sediment collected offshore of South Korea during the Second Ulleung Basin Gas Hydrate Expedition, UBGH2
1.0
data release
DOI:10.5066/P9S6S24N
Woods Hole Coastal and Marine Science Center, Woods Hole, MA
U.S. Geological Survey, Coastal and Marine Hazards and Resources Program
Suggested citation: Jang, J., Waite, W.F., Stern, L.A., and Lee, J.Y., 2022, Dataset of diatom controls on the sedimentation behavior of fine-grained sediment collected offshore of South Korea during the Second Ulleung Basin Gas Hydrate Expedition, UBGH2: U.S. Geological Survey data release, https://doi.org/10.5066/P9S6S24N.
https://doi.org/10.5066/P9S6S24N
https://www.sciencebase.gov/catalog/item/621e6f70d34ee0c6b389a936
One of the primary goals of South Korea’s second Ulleung Basin Gas Hydrate Expedition (UBGH2) was to examine the geotechnical properties of the marine sediment associated with methane gas hydrate occurrences found offshore of eastern Korea in the Ulleung Basin, East Sea. Methane gas hydrate is a naturally occurring crystalline solid that sequesters methane in individual molecular cages formed by a lattice of water molecules. During UBGH2, concentrated gas hydrate was found in two sedimentary environments: gas hydrate was found in thin, coarse-grained sediment layers interbedded with fine-grained sediment (fines, such as clays and muds) and as veins of essentially pure gas hydrate within predominantly fine-grained sediment. Methane gas hydrate is a potential energy resource, but the technical and economic viability of methane extraction from gas hydrate, in either of these marine environments associated with fine-grained sediments, is unknown as of 2022. This U.S. Geological Survey dataset provides insight into the reaction of diatomaceous fine-grained sediment particles to the pore water freshening that occurs when gas hydrate dissociates. To extract methane from gas hydrate, a “production” well is drilled down into the gas hydrate-bearing reservoir. The gas hydrate reservoir can be depressurized by drawing pore water out of the sediment through the production well to reduce the reservoir’s pore pressure. As the pore pressure falls below the gas hydrate stability limit, the solid gas hydrate breaks down, releasing gas and water, which then migrate toward the production well for collection. Fine-grained sediment can be a problem when extracting methane from gas hydrate because they can become resuspended in the flow of fluid and gas toward the production well. As these fine-grained particles move, they can cluster and subsequently clog pore throats in the sediment, reducing permeability, which controls how easily methane can flow toward the extraction well. The type of fine-grained sediment particle, and the chemistry of the surrounding pore water are the two main factors that determine the cluster structure (the size and fabric of the cluster), and how fast those clusters form and settle. Fine-grained particles interact with each other primarily in response to electrical forces, so changes in pore water chemistry can substantially alter how those forces are transferred between particles. In marine systems, in-situ pore water is an electrically conductive brine. As gas hydrate dissociates, however, fresh water is released along with the methane, making the pore water less conductive. In this study, fine-grained sediment samples from four UBGH2 sites are examined to better understand how the high diatom content (~22-45% by volume) of the sediment contributes to the sediment clustering and settling rate behavior. The term diatom refers here to the silica-based skeletal remains of microalgae. Diatom skeletons and skeleton fragments become buried in marine sediment when the microalgae die. Their presence can alter the clustering and settling rate of the sediment because diatoms have a lower density than most fine-grained sediment particles and can be several times larger than the typical sediment grain sizes found in the specimens studied. Diatoms can be up to 200 micrometers across, whereas the median grain size for the samples is about 10 micrometers. Specimens from the UBGH2 expedition were observed during sedimentation (settling) tests in pore fluids of differing chemistry. The results of the observations indicate the fine-grained UBGH2 sediments follow the expected behavior for diatoms in that they are extremely sensitive to the presence of low salinity levels. Even the freshening of pore water as a result of the dissociation of adjacent gas hydrate is not likely to increase the tendency of these fine-grained sediments to resuspend during the depressurization of reservoirs due to the diatom sensitivity even to low salinities.
As sediment settles in fluid, one or more fluid-sediment interfaces tend to form and move over time. Tracking the position of the accumulated and depositional interfaces (defined in the attribute labels below and in the browse graphic) over time in different fluids yield insights into the dependence of interparticle interactions on fluid chemistry. This pore fluid chemistry dependence can indicate which sediment components control sediment properties such as water content and compressibility that depend on the sediment fabric that forms as sediment particles settle. Sedimentation data presented here establish that diatoms in the fine-grained sediment from several methane gas hydrate-rich sites in the Ulleaung Basin offshore South Korea provide the dominant controls on how the sampled sediment settles.
In addition to funding from the U.S. Geological Survey Gas Hydrate Project, this work is sponsored in part by the Department of Energy (DOE) through interagency agreements with the U.S. Geological Survey’s Gas Hydrate Project (DE-FE0023495, DE-FE00-26166 and 89243320SFE000013). This work is also part of ongoing work related to the UBGH2 Expedition, offshore Korea. Links to related data and publications within the UBGH2 project are collected in the USGS Energy Program website: https://energy.usgs.gov/GeneralInfo/EnergyNewsroomAll/TabId/770/ArtMID/3941/ArticleID/810/Korean-National-Gas-Hydrate-Program-Second-Ulleung-Basin-Gas-Hydrate-Drilling-Expedition-.aspx, and published papers from the 2013 special volume of the Journal of Marine and Petroleum Geology dedicated to the UBGH2 Expedition are listed at the journal website: https://www.sciencedirect.com/journal/marine-and-petroleum-geology/vol/47/suppl/C.
20100709
20100930
ground condition of the field activity when the samples were collected
None planned.
130.34403
130.90692
36.66306
36.71180
None
U.S. Geological Survey
USGS
Woods Hole Coastal and Marine Science Center
WHCMSC
Coastal and Marine Hazards and Resources Program
CMHRP
fine-grained sediment
diatoms
deionized water
brine
settling
ISO 19115 Topic Category
oceans
geoscientificInformation
USGS Thesaurus
earth material properties
soil sciences
core analysis
laboratory experiments
gas hydrate resources
diatoms
USGS Metadata Identifier
USGS:621e6f70d34ee0c6b389a936
None
East Sea
Ulleung Basin
South Korea
None.
Public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey as the originator of the dataset.
U.S. Geological Survey
William F. Waite
Research Geophysicist
mailing and physical
384 Woods Hole Road
Woods Hole
Massachusetts
02543-1598
USA
508-548-8700 x2346
508-457-2310
wwaite@usgs.gov
https://www.sciencebase.gov/catalog/file/get/621e6f70d34ee0c6b389a936?name=UBGH2_Sedimentation_Apparatus_BrowseGraphic_Diatom.png
Sediment settling tubes showing the accumulation and depositional interfaces after 1440 minutes of settling: accumulation interface (blue arrows) separates the settled particles from the overlying particles that have yet to settle; the depositional interface (red arrows) separates the cloudy, particle-filled fluid from the overlying clear fluid out of which the particles have already settled.
PNG
https://www.sciencebase.gov/catalog/file/get/621e6f70d34ee0c6b389a936?name=UBGH2_Sedimentation_ExamplePlot.png
Sedimentation dependence on pore fluid chemistry for UBGH2-2-2B 11H-4 (Depositional interface, open symbols; Accumulation interface, solid symbols). The sedimentation pattern is typical of diatoms, which will settle rapidly even when the pore fluid salinity is low (e.g., rapid settling for the DWS specimen, blue circles, for which the fluid is deionized water with only the salt left over from the initial drying of the samples after collection in 2009).
PNG
The settlement tubes used in this work were all cut from the same acrylic tube, and thus are all nominally the same diameter. Equal heights of sediment and liquid were used in each test, each specimen was tested in the same set of liquids, and agitation times prior to allowing the system to settle were equivalent. This dataset covers the point-by point measurements of the sediment interfaces over time.
The accumulation interfaces were not always observable for the entirety of each settling test. In general, as sediment settles, the sediment suspended above the accumulation interface becomes more concentrated and can become concentrated enough to obscure the accumulation interface. Blank interface height entries within a column of measured data occur because the accumulation interface height in question could not be resolved at the stated measurement time.
Fugro Survey Pte Ltd (FSPL) of Singapore provided surface positioning for navigation onboard the D/V Fugro Synergy. Their position utilized the Starfix Series and a Kongsberg HiPAP 500 Ultra Short Baseline (USBL) system for determining the drill string position at each location in local datum. A transponder mounted on the ship's remotely-operated vehicle, and a Compatt beacon mounted on the Seacalf seabed frame, were used for determining the subsurface-positioning. A calibration of the vessel’s HiPAP 500 USBL system was carried out at approximately 2,200 meters below sea surface near one site. The results of this calibration were entered into the Starfix USBL software for use in the subsequent UBGH2 operations. Horizontal position accuracy is considered to be within 15 meters radius.
The depth of each sample was estimated by using the length of the drill string in conjunction with a direct observation by an ROV of when the drill bit made contact with the sea floor. This overall depth is then combined with the depth within the recovered core. The D/V Fugro Synergy approach to establishing the specimen depth is follow the same general principles as the International Ocean Drilling Program (http://www.iodp.org/policies-and-guidelines/142-iodp-depth-scales-terminology-april-2011/file), with an overall depth resolution ranging from 0.01 to 1 meter.
Deployment sample collection: All specimens were collected from the working half of split cores collected from 20100709 – 20100930. After sampling, the specimens were oven-dried and packed in airtight specimen bags.
20100930
Korea Institute of Geoscience and Mineral Resources
Joo Yong Lee
Research Geophysicist
mailing and physical
124, Gwahak-ro Yuseong-gu
Daejeon
South Chungcheong
34132
Korea
+82-042-868-3219
jyl@kigam.re.kr
Laboratory sampling: After the shipboard specimen collection and testing, a subset of the specimens was tested for mineralogy via x-ray diffraction (XRD). For the XRD, CuK-alpha radiation at 40 kV and 20 mA was used in a Philips X’pert MPD diffractometer. The XRD analyses were conducted using the software program SIROQUANT that utilized Rietveld quantification methods for improved assessment of diatom content in each specimen. Following XRD testing, the dry specimens were shipped at ambient temperatures to the Woods Hole Coastal and Marine Science Center (WHCMSC), where they were subsampled for the sediment settling tests.
2018
Korea Institute of Geoscience and Mineral Resources
Joo Yong Lee
Research Geophysicist
mailing and physical
124, Gwahak-ro Yuseong-gu
Daejeon
South Chungcheong
34132
South Korea
+82-042-868-3219
jyl@kigam.re.kr
Specimen set-up: After oven-drying a sediment specimen, sediment was spooned into a 25.4 mm diameter acrylic settling tube (settling tube pictured in the landing page browse graphic). Gentle pluviation of the sediment into the settling tube using the spoon created a loose-packed (maximum void ratio) fabric with a sediment height of 25.4 mm. The sediment was then mixed with a one of the test fluids to a final height of 152.4 mm to obtain a ratio of one to six in the diameter to height of the fluid column. The mixture was allowed to stabilize for more than twelve hours before the cylinder was evacuated in order to remove gas from the fluid. After degassing the fluid, the headspace was reopened to the atmosphere momentarily before a new stopper was inserted into the cylinder top to seal the specimen and water for the duration of the test. The sealed cylinder was shaken for one minute before being left to settle undisturbed.
2019
Dong-A University
Junbong Jang
Assistant Professor
mailing and physical
37 Nakdong-daero 550beon-gil, Saha-gu
Busan
Busan
49315
South Korea
+82-51-200-7622
jjang@dau.ac.kr
Measurement: Heights of the depositional interface and the accumulated sediment interface were measured as functions of time until the interface locations stabilized (one to four days, see browse graphic for example of sedimentation behavior). Measurement intervals increased with time in an approximately logarithmic fashion over the course of a complete test to capture time-varying behavior of the sedimentation. Time measurements were made with a stopwatch, and had a precision of ± 0.2 min. Height measurements were made with a ruler affixed to the cylinder, and had a precision of ± 0.1 mm.
2019
Dong-A University
Junbong Jang
Assistant Professor
mailing and physical
37 Nakdong-daero 550beon-gil, Saha-gu
Busan
Busan
49315
South Korea
+82-51-200-7622
jjang@dau.ac.kr
Fluid preparation: Each specimen was tested in more than one fluid. When the original marine sediment was dried, salt from the in situ pore-fluid precipitated as a solid material. Thus, the initial laboratory mixture of dry sediment with deionized water contained dissolved salt from the in situ pore water, and was identified as a “deionized water with salt” sample (DWS). In order to reduce the effect of salt, approximately 80% of the supernatant fluid in the cylinder was removed after the initial sedimentation test. The cylinder was refilled with deionized water, so the mixture contained freshened water and was identified as a “deionized water, freshened” sample (DWF). The sedimentation test was repeated with the freshened water mixture. Separately, subsamples of the original marine sediment were dried and tested with their in situ salts, using a 2M-brine solution (2M-brine = 2 Molar brine = 2 moles of NaCl in 1 liter of water) and also in a dispersant, sodium hexametaphosphate ((NaPO3)6). Sediment mixtures with 2M-brine and sodium hexametaphosphate were not recycled in the sedimentation tests.
2019
Dong-A University
Junbong Jang
Assistant Professor
mailing and physical
37 Nakdong-daero 550beon-gil, Saha-gu
Busan
Busan
49315
South Korea
+82-51-200-7622
jjang@dau.ac.kr
Data archiving: Microsoft Excel version 16.16.11 was used to consolidate all data in a spreadsheet. Measured interface heights and elapsed times were arranged by sediment and pore fluid type. Results were then exported to a comma-separated values (csv) file format.
2019
U.S. Geological Survey
William F. Waite
Research Geophysicist
mailing and physical
384 Woods Hole Road
Woods Hole
Massachusetts
02543-1598
USA
508-548-8700 x2346
508-457-2310
wwaite@usgs.gov
Point
0.00001
0.00001
decimal degrees
D_WGS_1984
WGS_1984
6378137.000000
298.257224
Meters below sea floor
1
meters
Attribute values
UBGH2_Sedimentation_Diatom_Data
Depositional and accumulated sediment interface heights of UBGH2 (Ulleung Basin, offshore Korea) sediment specimens allowed to settle in various fluids to test the sedimentation dependence on diatom content.
U.S. Geological Survey
Site
Site: UBGH2 site name designation. Format is: Expedition Name (UBGH2)-Site Number (2-2, 3, 6 or 11) and Hole Designation Letter (B or C) within that site.
Korea Institute of Geoscience and Mineral Resources (KIGAM)
Character set (text).
Core
CoreID: Unique identifier given to each collected sediment core at the designated site.
Shipboard science party, D/V Fugro Synergy
Character set (text).
Latitude (degrees, minutes, seconds)
Latitude_DMS: Latitude coordinate, in degrees (°) minutes (’) decimal seconds (”), of the sample’s location. North latitude recorded as positive values.
Shipboard science party, D/V Fugro Synergy
36°39'47.0"
36°42'42.4"
degrees (°) minutes (’) decimal seconds (”)
Longitude (degrees, minutes, seconds)
Longitude_DMS: Longitude coordinate, in degrees (°) minutes (’) decimal seconds (”), of the sample’s location. East longitude is recorded as positive values.
Shipboard science party, D/V Fugro Synergy
130°20'38.5"
130°54'24.9"
degrees (°) minutes (’) decimal seconds (”)
Latitude (decimal degrees)
Lat_DD: Latitude coordinate, in decimal-degrees, of sample’s location. North latitude recorded as positive values.
Shipboard science party, D/V Fugro Synergy
36.66306
36.71180
decimal degrees
Longitude (decimal degrees)
Long_DD: Longitude coordinate, in decimal degrees, of the sample’s location. East longitude is recorded as positive values.
Shipboard science party, D/V Fugro Synergy
130.34403
130.90692
decimal degrees
Water depth, mbsl
WD__mbsf: Seafloor depth in meters below seal level (mbsl).
Shipboard science party, D/V Fugro Synergy
897.8
2092.2
meters
Subsurface Depth, mbsf
Subsurf_Depth_mbsf: Depth of sample in meters below the sea floor (mbsf).
Shipboard science party, D/V Fugro Synergy
44
117
meters
Diatom Content (% by volume)
Diatom_Percent_By_Volume: Diatom concentration is based on the x-ray diffraction (XRD) assessment of Opal-A content in the specimen. Opal-A is an amorphous (non-crystalline) material, and in marine sediment, Opal_A is primarily associated with biogenic silica. In this study region, diatom skeletons are the main form of biogenic silica.
U.S. Geological Survey
22.3
33.7
percent by volume
Sieve Number
SieveNumber: Standard identification of the sieve size (sieve number) used to remove the coarsest grains from the specimens.
ASTM E11-17, Standard Specification for Woven Wire Test Sieve Cloth and Test Sieves, ASTM International, West Conshohocken, PA, 2017, www.astm.org/Standards/E11
40
50
sieve number
Sieve Mesh Size, micrometers
MeshSize_micrometers: Standard identification of the sieve size (in micrometers) used to remove the coarsest grains from the specimens.
ASTM E11-17, Standard Specification for Woven Wire Test Sieve Cloth and Test Sieves, ASTM International, West Conshohocken, PA, 2017, www.astm.org/Standards/E11
300
425
micrometers
Elapsed Time [min]
Time_min: Time elapsed since well-mixed specimen was allowed to begin settling.
U.S. Geological Survey
0.0833
1440
minutes
Depositional Interface, Freshened Water, mm
DWF_DepInt_mm: Each entry is the height of the interface between the settling sediment and the overlying fluid. Overlying fluid could be clear or it could be cloudy if sediment particles formed a colloidal suspension in the fluid. Blank entries indicate no measurement was made at the given time for that row. Explanation of "Freshened Water" is as follows: sediment is mixed with deionized water to obtain these data. As described in the process steps, the original specimen is dried, then saturated with deionized water to create the DWS specimen. That specimen is tested, then approximately 80% of the supernatant fluid in the cylinder is removed after the initial sedimentation test. The cylinder is refilled with deionized water, so the mixture contains freshened water and is identified as a “deionized water, freshened” sample (DWF). Thus, the DWF specimen is considered to have the freshest (lowest salt content) water.
U.S. Geological Survey
31.115
152.4
millimeters
Accumulation Interface, Freshened Water, mm
DWF_AccInt_mm: Each entry is the height of the interface between the accumulated sediment at the base of the specimen and the overlying mixture of sediment and fluid that is still settling. Entries that are equal to the corresponding Depositional Interface Height indicate specimens exhibiting uniform sedimentation (all particles or particle clusters falling at the same rate). Entries that are less than the corresponding Depositional Interface Height indicate specimens exhibiting Segregated Sedimentation (larger particles or particle clusters falling faster than smaller particles or particle clusters). Blank entries indicate no measurement was made at the given time for that row. As noted above, the DWF specimen is considered to have the freshest (lowest salt concentration) water.
U.S. Geological Survey
1.27
29.845
millimeters
Depositional Interface, Dissolved Salt Water, mm
DWS_DepInt_mm: Each entry is the height of the interface between the settling sediment and the overlying fluid. Overlying fluid could be clear or it could be cloudy if sediment particles formed a colloidal suspension in the fluid. Blank entries indicate no measurement was made at the given time for that row. Explanation of "Dissolved Salt Water" is as follows: sediment is mixed with deionized water to obtain these data. As described in the process steps, the original specimen is dried, then saturated with deionized water to create the DWS specimen. Because the salts in the original specimen remain in the specimen for this test, this specimen has a higher salt content than the DWF specimen. Because of the amount of fluid used for the settling test compared to the amount of sediment, the DWS fluid has a salinity that is less than the in situ salinity, however.
U.S. Geological Survey
28.067
152.4
millimeters
Accumulation Interface, Dissolved Salt Water, mm
DWS_AccInt_mm: Each entry is the height of the interface between the accumulated sediment at the base of the specimen and the overlying mixture of sediment and fluid that is still settling. Entries that are equal to the corresponding Depositional Interface Height indicate specimens exhibiting uniform sedimentation (all particles or particle clusters falling at the same rate). Entries that are less than the corresponding Depositional Interface Height indicate specimens exhibiting Segregated Sedimentation (larger particles or particle clusters falling faster than smaller particles or particle clusters). Blank entries indicate no measurement was made at the given time for that row. As noted above, the DWS specimen is considered to have a higher salt content (salinity) than the DWF specimen, but less than the in situ salinity.
U.S. Geological Survey
0
29.845
millimeters
Depositional Interface, 2M Brine, mm
2M_DepInt_mm: Each entry is the height of the interface between the settling sediment and the overlying fluid. Overlying fluid could be clear or it could be cloudy if sediment particles formed a colloidal suspension in the fluid. Blank entries indicate no measurement was made at the given time for that row. Explanation of "2M Brine" is as follows: sediment is mixed with brine (2M NaCl) to obtain these data. Because this test is run on the original sediment after drying, the specimen still contains the salt from the in situ environment. This salt is then dissolved in the 2M brine, so the final salinity is higher than 2M. The 2M Brine specimen has the highest salinity of any of the specimens tested here.
U.S. Geological Survey
28.702
152.4
millimeters
Accumulation Interface, 2M Brine, mm
2M_AccInt_mm: Each entry is the height of the interface between the accumulated sediment at the base of the specimen and the overlying mixture of sediment and fluid that is still settling. Entries that are equal to the corresponding Depositional Interface Height indicate specimens exhibiting uniform sedimentation (all particles or particle clusters falling at the same rate). Entries that are less than the corresponding Depositional Interface Height indicate specimens exhibiting Segregated Sedimentation (larger particles or particle clusters falling faster than smaller particles or particle clusters). Blank entries indicate no measurement was made at the given time for that row. Sediment is mixed with brine (2M NaCl) to obtain these data. As noted above, the 2M Brine specimen has the highest salinity of any of the specimens tested here.
U.S. Geological Survey
1.27
17.145
millimeters
Depositional Interface, Sodium Hexametaphosphate, mm
NaPO3_DepInt_mm: Each entry is the height of the interface between the settling sediment and the overlying fluid. Overlying fluid could be clear or it could be cloudy if sediment particles formed a colloidal suspension in the fluid. Blank entries indicate no measurement was made at the given time for that row. Explanation of "Sodium Hexametaphosphate" is as follows: sediment is mixed with the dispersant Sodium Hexametaphosphate ((NaPO3)6) to obtain these data. Unlike the ions of salt (NaCl), which remain as a dissolved phase in the water, the ions from (NaPO3)6 adsorb onto the sediment particles, meaning the particles all have the same type of surface electrical charge. Like charges repel, so the particles experience electrical repulsion that can help to keep the sediment particles separate (dispersed), hindering sedimentation.
U.S. Geological Survey
101.6
152.4
millimeters
Accumulation Interface, Sodium Hexametaphosphate, mm
NaPO3_AccInt_mm: Each entry is the height of the interface between the accumulated sediment at the base of the specimen and the overlying mixture of sediment and fluid that is still settling. Entries that are equal to the corresponding Depositional Interface Height indicate specimens exhibiting uniform sedimentation (all particles or particle clusters falling at the same rate). Entries that are less than the corresponding Depositional Interface Height indicate specimens exhibiting Segregated Sedimentation (larger particles or particle clusters falling faster than smaller particles or particle clusters). Blank entries indicate no measurement was made at the given time for that row. Sediment is mixed with the dispersant Sodium Hexametaphosphate ((NaPO3)6) to obtain these data. As noted above, (NaPO3)6 tends to disperse the particles, hindering sedimentation.
U.S. Geological Survey
0
30.353
millimeters
These data are available in a Microsoft Excel XLSX as well as a CSV format. The first two rows in the XLSX file are header rows, where the second row is an abbreviated column label intended for software packages that are unable to cope with longer labels available in the first row of the XLSX file. The first part of the attribute definition (before the colon) indicates the abbreviated column label. The first row of the CSV file is a header line and is the same as the abbreviated column label on the second row of the XLSX file.
U.S. Geological Survey
U.S. Geological Survey - ScienceBase
mailing and physical
Denver Federal Center, Building 810, Mail Stop 302
Denver
CO
80225
1-888-275-8747
sciencebase@usgs.gov
This dataset contains five files: UBGH2_Sedimentation_Diatom_Data.xlsx (data in an Excel spreadsheet), UBGH2_Sedimentation_Diatom_Data.csv (same data in a comma-separated text file), UBGH2_Sedimentation_BrowseGraphic.png (browse graphic), UBGH2_Sedimentation_ExamplePlot.png (example of how the data can be visualized) and FGDC CSDGM metadata in XML format.
Neither the U.S. Government, the Department of the Interior, nor the USGS, nor any of their employees, contractors, or subcontractors, make any warranty, express or implied, nor assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, nor represent that its use would not infringe on privately owned rights. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of these data or related materials. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
XLXS
Microsoft Excel version 16.58 (22021501)
The dataset contains the XLSX and CSV format of the data, a browse graphic and associated FGDC CSDGM metadata.
1
https://www.sciencebase.gov/catalog/file/get/621e6f70d34ee0c6b389a936
https://www.sciencebase.gov/catalog/item/621e6f70d34ee0c6b389a936
https://doi.org/10.5066/P9S6S24N
The first link downloads all the data on the landing page and provides them in a zip file, the second link goes to the dataset landing page where files can be downloaded individually, and the third link goes to the data release main landing page.
CSV
Microsoft Excel version 16.58 (22021501)
Comma-Separated Values exported from Excel
The dataset contains the XLSX and CSV format of the data, a browse graphic and associated FGDC CSDGM metadata.
1
https://www.sciencebase.gov/catalog/file/get/621e6f70d34ee0c6b389a936
https://www.sciencebase.gov/catalog/item/621e6f70d34ee0c6b389a936
https://doi.org/10.5066/P9S6S24N
The first link downloads all the data on the landing page and provides them in a zip file, the second link goes to the dataset landing page where files can be downloaded individually, and the third link goes to the data release main landing page.
None.
These data are available in XLSX and CSV formats, and a browse graphic in PNG format. The user must have software capable of reading the data formats.
20220630
U.S. Geological Survey
William F. Waite
Research Geophysicist
mailing and physical
384 Woods Hole Rd.
Woods Hole
MA
02543-1598
508-548-8700 x2346
508-457-2310
wwaite@usgs.gov
FGDC Content Standards for Digital Geospatial Metadata
FGDC-STD-001-1998