TY - JOUR
T1 - Two anomalies of platinum group elements above the Cretaceous-Tertiary boundary at Beloc, Haiti
T2 - Geochemical context and consequences for the impact scenario
AU - Stüben, Doris
AU - Kramar, Utz
AU - Berner, Zsolt
AU - Eckhardt, Jörg Detlef
AU - Stinnesbeck, Wolfgang
AU - Keller, Gerta
AU - Adatte, Thierry
AU - Heide, Klaus
PY - 2002/1/1
Y1 - 2002/1/1
N2 - 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.
AB - 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.
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U2 - 10.1130/0-8137-2356-6.163
DO - 10.1130/0-8137-2356-6.163
M3 - Article
SN - 0072-1077
VL - 356
SP - 163
EP - 188
JO - Special Paper of the Geological Society of America
JF - Special Paper of the Geological Society of America
ER -