Publication Date:
2024-01-09
Description:
Fourteen samples spanning a 2.5 m interval that includes the Cretaceous-Tertiary (K/T) boundary from Hole 752B near the crest of Broken Ridge in the eastern Indian Ocean, were studied in order to search for anomalous enrichments of iridium (Ir) and shock-metamorphosed quartz grains. No allogenic quartz grains 〉10 µm were observed, hence the presence of quartz containing diagnostic evidence of shock-metamorphism could not be confirmed. Two Ir anomalies of 2.2±0.6 and 2.0±0.4 parts per billion (ppb) were measured in samples of dark green ash-bearing chalk at depths of 357.93 and 358.80 mbelow seafloor (mbsf), respectively, (Samples 121-752B-11R-3, 13-14 cm, and 121-752B-11R-3, 100-101 cm) using conventional Instrumental Neutron Activation Analysis (INAA). These samples containing anomalous enrichments of Ir were taken from approximately 82 cm above and 5 cm below the extinction level of Globotruncanids. Our results are consistent with those of Michel et al. (this volume), who observe elevated concentrations of Ir at these depths in addition to a larger Ir anomaly associated with the extinction level of Globotruncanids.
Keywords:
121-752B; Antimony; Antimony, standard deviation; Arsenic; Arsenic, standard deviation; Barium; Barium, standard deviation; Caesium; Caesium, standard deviation; Calcium oxide; Calcium oxide, standard deviation; Cerium; Cerium, standard deviation; Chromium; Chromium, standard deviation; Cobalt; Cobalt, standard deviation; Comment; DEPTH, sediment/rock; DRILL; Drilling/drill rig; DSDP/ODP/IODP sample designation; Europium; Europium, standard deviation; Gold; Gold, standard deviation; Hafnium; Hafnium, standard deviation; Identification; Iridium; Iridium, standard deviation; Iron oxide, FeO; Iron oxide, FeO, standard deviation; Joides Resolution; Lanthanum; Lanthanum, standard deviation; Leg121; Lutetium; Lutetium, standard deviation; Neodymium; Neodymium, standard deviation; Nickel; Nickel, standard deviation; Ocean Drilling Program; ODP; Potassium oxide; Potassium oxide, standard deviation; Rubidium; Rubidium, standard deviation; Samarium; Samarium, standard deviation; Sample code/label; Sample mass; Scandium; Scandium, standard deviation; Selenium; Selenium, standard deviation; Sodium oxide; Sodium oxide, standard deviation; South Indian Ridge, South Indian Ocean; Strontium; Strontium, standard deviation; Tantalum; Tantalum, standard deviation; Terbium; Terbium, standard deviation; Thorium; Thorium, standard deviation; Uranium; Uranium, standard deviation; Ytterbium; Ytterbium, standard deviation; Zirconium; Zirconium, standard deviation
Type:
Dataset
Format:
text/tab-separated-values, 938 data points
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