TY - JOUR
T1 - Biogeochemical contrasts between mid-Cretaceous carbonate platforms and Cenozoic reefs
AU - Iryu, Yasufumi
AU - Yamada, Tsutomu
PY - 1999/12/1
Y1 - 1999/12/1
N2 - Carbonate sediments of mid-Cretaceous platforms on Allison and Resolution Guyots, Mid-Pacific Mountains (ODP Leg 143, Sites 865, 866, 867 and 868) and those of upper Oligocene to Pliocene reefs of the Kita-daito-jima Borehole were studied. The mid-Cretaceous platforms abound with abiotic (?) precipitates (ooids) and microbial carbonate grains/sediments (oncoids and 'algal' laminites), whereas the Cenozoic reefs consist mainly of coral and non-geniculate coralline algae, major frame-builders, benthic foraminifers and codiacean alga (Halimeda). There exists a remarkable difference in a mode of calcification between the mid-Cretaceous platforms and Cenozoic reefs. The major reef-builders of Cenozoic reefs precipitated carbonates within closed to semiclosed spaces within their bodies. In contrast, the mid-Cretaceous platforms contain abundant grains/sediments formed by chemical (?) precipitations and biotic extracellular calcification. This contrasting feature reflects different modes of biogeochemical cycles between the mid-Cretaceous and Cenozoic. Increased CO2 (degassed by active volcanism) and resultant high temperature and intensive weathering may have brought high concentration of Ca2+ and HCO3- into the mid-Cretaceous sea, which enhanced abiotic and extracellular calcification. Inverse processes are true for the Cenozoic.
AB - Carbonate sediments of mid-Cretaceous platforms on Allison and Resolution Guyots, Mid-Pacific Mountains (ODP Leg 143, Sites 865, 866, 867 and 868) and those of upper Oligocene to Pliocene reefs of the Kita-daito-jima Borehole were studied. The mid-Cretaceous platforms abound with abiotic (?) precipitates (ooids) and microbial carbonate grains/sediments (oncoids and 'algal' laminites), whereas the Cenozoic reefs consist mainly of coral and non-geniculate coralline algae, major frame-builders, benthic foraminifers and codiacean alga (Halimeda). There exists a remarkable difference in a mode of calcification between the mid-Cretaceous platforms and Cenozoic reefs. The major reef-builders of Cenozoic reefs precipitated carbonates within closed to semiclosed spaces within their bodies. In contrast, the mid-Cretaceous platforms contain abundant grains/sediments formed by chemical (?) precipitations and biotic extracellular calcification. This contrasting feature reflects different modes of biogeochemical cycles between the mid-Cretaceous and Cenozoic. Increased CO2 (degassed by active volcanism) and resultant high temperature and intensive weathering may have brought high concentration of Ca2+ and HCO3- into the mid-Cretaceous sea, which enhanced abiotic and extracellular calcification. Inverse processes are true for the Cenozoic.
KW - Biogeochemical cycle
KW - Carbonate platform
KW - Cenozoic
KW - Cretaceous
KW - Reef
UR - http://www.scopus.com/inward/record.url?scp=0033491112&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0033491112&partnerID=8YFLogxK
U2 - 10.1046/j.1440-1738.1999.00250.x
DO - 10.1046/j.1440-1738.1999.00250.x
M3 - Article
AN - SCOPUS:0033491112
VL - 8
SP - 475
EP - 490
JO - Island Arc
JF - Island Arc
SN - 1038-4871
IS - 4
ER -