Chemistry and mineralogy across the Cretaceous/Tertiary boundary at DSDP Site 527, Walvis Ridge, South Atlantic Ocean

The Cretaceous-Tertiary boundary on the Pacific plate: Composition and distribution of impact debris

“…There are no quantitative data to compare shocked-quartz fluences in the Pacific to those elsewhere. However, in contrast to analyses of quartz in European (e.g., Izett, 1990), South Atlantic (Huffman et al, 1990), and Indian Ocean (Thierstein et al, 1991) localities, shocked quartz constitutes the major fraction of nonopaque mineral grains >30 µm in trace mineral residues.…”

Calcareous nannoplankton mass extinction at the Cretaceous/Tertiary boundary: An update

“…The deep-sea Site 527 (Fig. 9) shows the onset of the decline in the percent abundance of Cretaceous species, which correlates with the iridium anomaly and a 30% drop in carbonate (Huffman et al, 1990). A 1.0 per mil negative shift in δ 13 C and a nearly 0.5 per mil positive shift in δ 18 O (bulk sediment) are noted at this level by Shackleton and Hall (1984).…”

“…Deep Sea Drilling Project (DSDP) Sites 524 through 529 on the Walvis Ridge produced several important K/T papers (e.g., Hsü et al, 1982;Perch-Nielsen et al, 1982;Boersma, 1984;Manivit, 1984;Huffman et al, 1990;Alcalá-Herrera et al, 1993;Gartner et al, 1994).…”

“…The mid-and higher-latitude sections are dominated by Zygodiscus sigmoides in NP1 with Markalius inversus and Biscutum castrorum (= B. constans of Figure 9. Cretaceous nannofossil percent abundance correlated with Ir (ppb = parts per billion) and % carbonate (Huffman et al, 1990) and with bulk-sample carbon and oxygen isotopes (Shackleton and Hall, 1984). mbsf = meters below seafloor.…”

The size and abundance of shocked quartz in Cretaceous-Tertiary boundary sediments from the Pacific Basin

“…Bohor and Betterton (1989) recovered shocked-quartz grains as large as 300 µm from marine sediment in samples from DSDP Site 603B off the coast of North Carolina, where large grains might be expected. In a study of quartz from the K/T boundary at DSDP Site 527, Walvis Ridge, South Atlantic, Huffman et al (1990) found that only 2% of the quartz in K/T boundary sediments contained PDFs and that nearly all of these were <63 µm in diameter. No shocked quartz was found in the K/T boundary clay at ODP Site 738, southern Indian Ocean (Thierstein et al, 1991).…”