An official website of the United States government
This dataset contains geochemical and grain size measurements of seabed and suspended sediment samples collected from the Bering Shelf and Yukon prodelta in June 2023. These samples were collected during the 6-12 June 2023 Arctic Chief Scientist Training Cruise, which was a short cruise on the R/V Sikuliaq during its transit from Seward, Alaska to Nome, Alaska. The cruise was sponsored by the University National Oceanographic Laboratory System (UNOLS) Arctic Icebreaker Coordinating Committee and the National Science Foundation. These data were generated as a pilot data set to understand the fate of terrestrial organic carbon in the Yukon River delta and adjacent Bering Sea. Seabed sediment was collected at three locations (MC04, MC06, and MC08) using a multicorer. One seabed sediment sample was collected using a van veen grab sampler. Suspended sediment samples were collected using a hand-deployed niskin bottle and transferred into a clean 10-liter cubitainer for transport and temporary storage. Suspended sediment was filtered on the ship within 24 hours of collection using a Geotech barrel filter with a 0.45 micron Polyethersulfone (PES) membrane filter. Multicores were extruded on deck and subsamples were transferred to sterile whirl-pak sample bags. All sediment samples were frozen and subsequently shipped back to the lab in coolers. Sediment samples were analyzed for grain size, bulk elemental composition via X-ray fluorescence (XRF), and organic carbon and nitrogen concentrations and isotopes via EA-IRMS (elemental analyzer-isotope ratio mass spectrometry). Grain size distributions were measured using a Malvern mastersizer laser diffraction particle size analyzer at the University of Colorado Boulder. Bulk elemental composition was measured on the Rigaku XRF in the Analytical Geochemistry Lab at the University of New Mexico. Total organic carbon (TOC), total nitrogen (TN), and carbon/nitrogen isotopes were measured at the Center for Stable Isotopes at the University of New Mexico. Prior to EA-IRMS analyses, sediment samples were acid-treated to remove inorganic carbon following the method of Galy et al., 2007. References Galy, V., Bouchez, J., & France‐Lanord, C. (2007). Determination of total organic carbon content and δ13C in carbonate‐rich detrital sediments. Geostandards and Geoanalytical research, 31(3), 199-207.
more »
« less
Major and trace element analyses of Eocene-Oligocene marine sediments from ODP Site 696, South Orkney Microcontinent
This dataset contains measurements of major and trace elements on 190 samples of Eocene-Oligocene sediment from Ocean Drilling Program Site 696 drilled in 650 m water depth on the South Orkney Microcontinent. The composition of detrital, biogenic and authigenic sediment components was assessed via whole rock geochemistry of sediment samples. Instrument analysis was completed at Montclair State University.
more »
« less
- Award ID(s):
- 1743643
- PAR ID:
- 10603855
- Publisher / Repository:
- U.S. Antarctic Program (USAP) Data Center
- Date Published:
- Subject(s) / Keyword(s):
- IODP 650 IODP 696 Sediment Core Data Glaciation Provenance Weathering Paleoceanography Cryosphere Antarctica
- Format(s):
- Medium: X
- Location:
- Weddell Sea; (Latitude:-61.849; Longitude:-42.933)
- Right(s):
- Creative Commons Attribution 4.0 International
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Abstract Sea-level rise and settlement are investigated at Ta'ab Nuk Na, an ancient Maya salt works in Belize, by examining samples from wooden posts and marine sediment. The samples included Post 145 of Building B and the Nunavut beam, along with marine sediment columns cut from beside both wooden posts. The sediment columns were sampled at 2 cm intervals. Loss-on ignition confirmed the presence of organic material. Identifying the organic content involved removing nonorganic material from the sediment and sorting the organic material under magnification. This procedure established that most of the organic material was red mangrove (Rhizophora mangle). Red mangroves tolerate salt water, but under conditions of sea-level rise, the plants grow vertically to keep their leaves above water. Sediment, leaves, and detritus trapped in the prop roots form mangrove peat, which serves as a proxy for sea-level rise. AMS dating of fine red mangrove roots determined that the local sea levels rose at Ta'ab Nuk Na throughout the Late Classic period and continued into the Postclassic period. Radiocarbon dates obtained from the wood-post samples yielded Late Classic–period dates. Comparing the radiocarbon dates from the wooden posts and the sediment core samples determined that the site was abandoned before the rising seas flooded the area. Evidently, sea-level rise did not play a role in site abandonment.more » « less
-
Sea-level rise and settlement are investigated at Ta'ab Nuk Na, an ancient Maya salt works in Belize, by examining samples from wooden posts and marine sediment. The samples included Post 145 of Building B and the Nunavut beam, along with marine sediment columns cut from beside both wooden posts. The sediment columns were sampled at 2 cm intervals. Loss-on ignition confirmed the presence of organic material. Identifying the organic content involved removing nonorganic material from the sediment and sorting the organic material under magnification. This procedure established that most of the organic material was red mangrove (Rhizophora mangle). Red mangroves tolerate salt water, but under conditions of sea-level rise, the plants grow vertically to keep their leaves above water. Sediment, leaves, and detritus trapped in the prop roots form mangrove peat, which serves as a proxy for sea-level rise. AMS dating of fine red mangrove roots determined that the local sea levels rose at Ta'ab Nuk Na throughout the Late Classic period and continued into the Postclassic period. Radiocarbon dates obtained from the wood-post samples yielded Late Classic–period dates. Comparing the radiocarbon dates from the wooden posts and the sediment core samples determined that the site was abandoned before the rising seas flooded the area. Evidently, sea-level rise did not play a role in site abandonment.more » « less
-
Estuarine and coastal waterways are commonly monitored for fecal and sewage contamination to protect recreator health and ecosystem functions. Such monitoring programs commonly rely on cultivation-based counts of fecal indicator bacteria (FIB) in water column samples. Recent studies demonstrate that sediments and beach sands can be heavily colonized by FIB, and that settling and resuspension of colonized particles may significantly influence the distribution of FIB in the water column. However, measurements of sediment FIB are rarely incorporated into monitoring programs, and geographic surveys of sediment FIB are uncommon. In this study, the distribution of FIB and the extent of benthic-pelagic FIB coupling were examined in the urbanized, lower Hudson River Estuary. Using cultivation-based enumeration, two commonly-measured FIB, enterococci and Escherichia coli, were widely distributed in both sediment and water, and were positively correlated with each other. The taxonomic identity of FIB isolates from water and sediment was confirmed by DNA sequencing. The geometric mean of FIB concentration in sediment was correlated with both the geometric mean of FIB in water samples from the same locations and with sediment organic carbon. These two positive associations likely reflect water as the FIB source for underlying sediments, and longer FIB persistence in the sediments compared to the water, respectively. The relative representation of other fecal associated bacterial genera in sediment, determined by 16S rRNA gene sequencing, increased with the sequence representation of the two FIB, supporting the value of these FIB for assessing sediment contamination. Experimental resuspension of sediment increased shoreline water column FIB concentrations, which may explain why shoreline water samples had higher average FIB concentrations than samples collected nearby but further from shore. In combination, these results demonstrate extensive benthic-pelagic coupling of FIB in an urbanized estuary and highlight the importance of sediment FIB distribution and ecology when interpreting water quality monitoring data.more » « less
-
Grain size analysis is an essential tool for classifying sedimentary environments. The main aim of the current research is to use granulometric analysis of the Bhikiysain palaeolake sequence along the Ramganga river to describe changes in the depositional environment within the lake during the late Quaternary. The granulometric analysis was conducted using a laser particle size analyser on 32 samples, collected at 10 cm intervals in a vertical palaeolake profile, at Bhikiyasain (Ramganga Basin). The results of the grain-size analysis indicate that the size distribution of the sediment is unimodal. The unimodal size distribution of the sediment suggests that the sediment was supplied via fluvial action. The Bhikiyasain Basin (29°43.106’ N; 79°15.682’ E) underwent tectonic activity around 44 ka, resulting in the ponding of the Ramganga river and the formation of palaeolake deposit. Based on grain size analysis, variation in the colour and lithofacies, the entire profile has been divided into 6 different zones (zones 1 to 6). The silt has the highest concentration in all the zones except for zones 1 and 3. Zones with high silt concentration are inferred to represent low energy depositional environments during the time of deposition. The higher amount of sand concentration in zones 1 and 3 represent higher energy depositional environment. For the whole profile, the sorting of the samples varies between 1.1 and 2.0, indicating poor sorting of the samples. The poorly sorted sediment in all six zones represents limited transportation of sediment from the catchment and also suggests that the sediment was deposited in a low energy environment. The ternary plots also signify the dominance of silt followed by sand and clay. The skewness values range from 0.1 to 0.5 which indicates that the samples are symmetrical to very finely skewed. Variability in the skewness values may be due to changes in the intensity of wind and hydrodynamic conditions of the lake. The kurtosis value ranges from 0.9-1.4, indicating the samples are platykurtic, leptokurtic and mesokurtic in nature. Variability in the kurtosis may be due to changes in the flow characteristics of the depositional medium.more » « less
