A detailed geochemical investigation of an expanded Cretaceous-Tertiary (K-T) boundary section near Beloc (B3), Haiti, reveals a complex pattern of sedimentation of multiple origins as a result of erosional, biogenic, volcanic, and impact events. Carbonate-rich uppermost Maastrichtian sediments with high excess rates for Cu, Zn, and Sr (biogenic origin) indicate high productivity (δ13 C) and warm temperatures (δ18O). These sediments are overlain by Paleocene (early Danian zone P1a) spherule-rich clayey layers that indicate lower productivity, lower temperatures, and high input of glass and biogenic carbonate. Reworked Maastrichtian sediments are mixed with spherule-rich layers. This spherule-rich deposit is topped by a thin layer rich in Fe that also contains an Ir-dominated anomaly of platinum group elements (PGE) with an almost chondritic abundance pattern, which appears to be the result of a cosmic influx. Monotonous limestones above this interval reflect recovery to normal pelagic sedimentation, which is interrupted by a second PGE anomaly in an Fe-rich clayey layer in the middle part of zone P1a. All PGEs are enriched in this interval and the PGE pattern is basalt like, suggesting a volcanic source. Both PGE anomaly horizons coincide with productivity and temperature changes.
|Original language||English (US)|
|Number of pages||26|
|Journal||Special Paper of the Geological Society of America|
|State||Published - Jan 1 2002|
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