Stratigraphy of the basal Paleocene carbonate sequence and the impact breccia-carbonate contact in the Chicxulub crater; stable isotope study of the Santa Elena borehole rocks

Author(s): Urrutia-Fucugauchi, Jaime; Perez-Cruz, Ligia; Morales-Puente, Pedro; Escobar-Sánchez, J. Elia
Author Affiliation(s): Primary:
Universidad Nacional Autónoma de México, Instituto de Geofisica, Coyoacan, Mexico
Volume Title: International Geology Review
Source: International Geology Review, 50(1), p.75-83. Publisher: Winston & Son, Silver Spring, MD, United States. ISSN: 0020-6814 CODEN: IGREAP
Note: In English. 28 refs.; illus., incl. strat. cols., sketch map
Summary: We present results of a stable isotope study of the carbonate sedimentary sequence recovered in the Santa Elena borehole (located 110 km from the crater center) of the UNAM Scientific Drilling Program, immediately above the impact breccia-carbonate contact at a depth of 332 m. Sixty samples spaced in a 17 m thick section representing the basal Tertiary sequence were analyzed for oxygen and carbon isotopes. The δ13C ranges from about 1.2 to 3.5 per mil, and the δ18O ranges from about -1.4 to -4.8 per mil. We correlate the isotopic records for bulk carbonate for the Paleocene with the DSDP Hole 577, assuming a tie point for the Cretaceous/Paleocene (K/T) boundary. The variation pattern in the Santa Elena borehole correlates well with the global pattern defined for marine carbonate sediments. In the Santa Elena borehole, δ13C values are slightly more positive; δ13C values reach ∼3.5 per mil and there is a gradual increase from the Lower to the Middle Paleocene strata. The trend of δ18O values from Santa Elena borehole are also similar to δ18O DSDP Hole 577, however values in the Chicxulub Tertiary sequence are more negative; δ13C values reach ca. -4 per mil in the Lower Paleocene rocks. Paleomagnetic data for the study section document four geomagnetic polarity zones for the impact breccias and basal sedimentary sequence, which span from chron 29r (K/T boundary) to chron 28n. The combined stable isotope and magnetic polarity data provide a stratigraphic framework for the first 2.5 Ma after the K/T boundary, and permit inferences about the paleoceanographic conditions following the Chicxulub impact and into the Early Paleocene.
Year of Publication: 2008
Research Program: DSDP Deep Sea Drilling Project
IPOD International Phase of Ocean Drilling
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Breccia; C-13/C-12; Carbon; Carbonate rocks; Cenozoic; Chicxulub Crater; Correlation; Cretaceous; DSDP Site 577; Deep Sea Drilling Project; Drilling; IPOD; Isotope ratios; Isotopes; K-T boundary; Leg 86; Lower Paleocene; Mesozoic; Mexico; North Pacific; Northwest Pacific; O-18/O-16; Oxygen; Pacific Ocean; Paleocene; Paleogene; Santa Elena Borehole; Sedimentary rocks; Sequence stratigraphy; Shatsky Rise; Stable isotopes; Stratigraphic boundary; Tertiary; Upper Cretaceous; West Pacific; Yucatan Peninsula
Coordinates: N200000 N220000 W0860000 W0900000
Record ID: 2008106113
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