skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.


Title: Major, trace element and Sr-Nd-Hf-Pb isotope geochemistry of whole rock and glass basaltic samples from the Rio Grande Rise and Tarazed seamount chain, South Atlantic collected by the dredge sampling cruise NBP1808 with RV Nathanial B. Palmer
Whole rock major elements on ICP-OES by flux fusion or on trace element dissolutions, and trace elements by solution ICP-MS. Basaltic glass major elements by electron microprobe and trace elements by laser ICP-MS. Sr-Nd-Hf-Pb isotopes on MC-ICP-MS.  more » « less
Award ID(s):
1558734
PAR ID:
10517653
Author(s) / Creator(s):
;
Publisher / Repository:
Interdisciplinary Earth Data Alliance (IEDA)
Date Published:
Subject(s) / Keyword(s):
Regional (Continents, Oceans) Rio Grande Rise, Tristan-Gough mantle plume, major elements, trace elements
Format(s):
Medium: X Other: application/vnd.ms-excel
Location:
Rio Grande Rise and Tarazed seamount chain, South Atlantic
Sponsoring Org:
National Science Foundation
More Like this
  1. Trace element data measured by LA-ICP-MS analysis in crystal separates for lithospheric mantle xenoliths from south-central Vietnam. Samples are peridotite xenoliths from two alkali basalt locations in Vietnam, Pleiku and Xuan Loc. Data are trace elements measured by LA-ICP-MS in mineral separates. 
    more » « less
  2. Major and trace element geochemistry of lower Pliocene marine sediment core samples collected at International Ocean Discovery Program Site U1533 in the Amundsen Sea via ICP-MS. Bulk samples of mud or sandy mud were analyzed to assess sediment provenance using elemental ratios. The geochemical data were collected and analyzed by Olga Libman-Roshal and Sandra Passchier, assisted by Xiaona Li in the ICP-MS analytical work. 
    more » « less
  3. Isotope ratio analyses of trace elements are applied to tooth enamel, ostrich eggshell, and other archaeological hard tissues to infer mobility and other aspects of hominin and animal paleoecology. It has been assumed that these highly mineralized tissues are resistant to diagenetic alteration, but this is seldom tested and some studies document diagenetic alteration over brief time spans. Here, we build on existing research on Maximum Threshold Concentrations (MTCs) to develop screening tools for diagenesis that can inform heavy isotopic analyses. The premise of the MTC approach is that archaeological tissues are likely contaminated and unsuitable for isotope ratio analysis when they exceed characteristic modern concentration ranges of trace elements. Furthermore, we propose a new metric called the Maximum Threshold Ratio (MTR) of 85Rb/88Sr or whole element Rb/Sr, which can be measured simultaneously with 87Sr/86Sr during laser ablation (LA) MC-ICP-MS or applied during post hoc screening of specimens. We analyzed 56 enamel samples from modern Kenyan mammals and 34 modern ostrich eggshells from South Africa, Namibia, and the United States by solution ICP-MS, as well as a subset of shells using LA-MC-ICP-MS. Our results indicate that thresholds are consistent across taxa at a single location, but likely vary across locations. Therefore, MTCs and MTRs need to be tissue and locality specific, but not necessarily taxon-specific. Other important differences are observed between the inner and outer surfaces of the eggshells and between LA and solution ICP-MS. This exploratory study provides guidelines for building reference thresholds to screen enamel and eggshell for diagenesis potentially impacting biogenic isotope ratios. 
    more » « less
  4. Major and trace element geochemistry of lower Pliocene marine sediment core samples collected at International Ocean Discovery Program Site U1532 in the Amundsen Sea via ICP-MS. Bulk samples of mud or sandy mud were analyzed to assess sediment provenance using elemental ratios. The geochemical data were collected and analyzed by Ronald Leon and Sandra Passchier, assisted by Jessica Scheinbaum in sample preparations, and Xiaona Li in the ICP-MS analytical work. 
    more » « less
  5. The U-Pb system in titanite has been shown to be reset during a variety of high-temperature processes including high-temperature deformation, but post-deformation modification and recovery of crystal-lattice strain have so far made U-Pb equilibration mechanism from deformed titanites equivocal. Microstructures, including mechanical twinning and subgrain rotation recrystallization are more likely to be preserved at low-temperatures, but the systematics of chemical equilibration have not been established for these conditions. This study identifies progressive crystallographic misorientation and deformation twins in titanite porphyroclasts from the Wasatch Fault Zone, Utah, USA. The microstructures, mapped using electron backscatter diffraction (EBSD), developed at ~11 km depth during 300–400 ºC crystal-plastic deformation within the ductile fault zone. These microstructural maps were used to guide laser ablation-split stream ICP-MS analysis: U-Pb isotopes measured in tandem with major and trace element contents. Despite the low temperature, U-Pb and trace element contents in titanite equilibrated, at least partially, during deformation. Both major and trace elements in titanite also likely partitioned with a fluid and in response to the (re)crystallization of other mineral phases in the fault zone. Chemical zoning and crystal lattice recovery suggestive of fluid-aided recrystallization are absent, and the main mechanism for this resetting may instead be an enhancement of element mobility along microstructure dislocations. These processes are interpreted to record complex open-system behavior of titanite caused by crystal-plastic deformation during the initiation of the WFZ. This presentation will summarize the comparative analysis of microstructure by EBSD and titanite chemistry by LASS-ICP-MS, and how it bears on the understanding of elemental mobility in titanite during low-temperature crystal-plastic deformation. 
    more » « less