Isotopic composition of foraminifera from sediments of DSDP Legs 3, 6-9, 17

• Main Authors: Savin, Samuel M, Douglas, Robert G, Stehli, Francis G
• Format: Dataset
• Language: English
• Published: PANGAEA 1975
• Subjects: 17-167; 17-171; 3-15; 3-16; 3-17A; 3-20C; 3-21; 3-22; 6-44; 6-47; 6-55; 7-64; 8-71; 9-78; 9-80A; Deep Sea Drilling Project; DRILL; Drilling/drill rig; DSDP; ELT21; ELT21.003-PC; ELT24; ELT24.010-PC; ELT24.016-PC; Eltanin; Glomar Challenger; Leg17; Leg3; Leg6; Leg7; Leg8; Leg9; North Pacific/CONT RISE; North Pacific/GUYOT; North Pacific/PLAIN; North Pacific/PLATEAU; North Pacific/RIDGE; PC; Piston corer; South Atlantic/CONT RISE; South Atlantic/HILL; South Atlantic/VALLEY; South Pacific/PLATEAU; South Pacific/VALLEY; Antarctic; Pacific; Antarc*; Antarctica; Planktonic foraminifera; Sea ice
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.720968; https://doi.org/10.1594/PANGAEA.720968

Oxygen isotopic compositions of the tests of planktonic foraminifera from several Deep Sea Drilling Project sites provide a general picture of low-latitude marine temperatures from Maastrichtian time to the present. Bottom temperatures determined from the isotopic compositions of benthonic foraminifera are interpreted as being indicative of high-latitude surface temperatures. Prior to the beginning of middle Miocene time, high- and low-latitude temperatures changed in parallel fashion. Following an apparently small and short-lived drop in temperature near the Tertiary-Cretaceous boundary, temperatures remained warm and relatively constant through Paleocene and early and middle Eocene time; bottom temperatures then were on the order of 12°C. A sharp temperature drop in late Eocene time was followed by a more gradual lowering of temperature, culminating in a late Oligocene high-latitude temperature minimum of about 4°C. A temperature rise through early Miocene time was followed in middle Miocene time by a sudden divergence of high- and low-latitude temperatures: high-latitude temperatures dropped dramatically, perhaps corresponding to the onset of major glaciation in Antarctica, but low-latitude temperatures remained constant or perhaps increased. This uncoupling of high-and low-latitude temperatures is postulated to be related to the establishment of a circum-Antarctic circulation similar to that of today. A further drop in high-latitude temperatures in late Pliocene time probably signaled the onset of a major increase in polar glaciation, including extensive sea-ice formation. Early Miocene, small-amplitude (1 per mil) sympathetic fluctuations in isotopic compositions of planktonic and benthonic foraminifera have been identified. These have a period of several hundred thousand years. Superimposed upon these are much more rapid and smaller fluctuations (0.2 to 0.5 per mil) with a period of about 80000 to 90000 yr. This is similar to the period observed for Pleistocene isotopic temperature fluctuations. In low ...