Alternating Southern and Northern Hemisphere climate response to astronomical forcing during the past 35 m.y.

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doi: 10.1130/G38663.1
Author(s): de Vleeschouwer, David; Vahlenkamp, Maximilian; Crucifix, Michel; Palike, Heiko
Author Affiliation(s): Primary:
Universität Bremen, MARUM-Center for Marine Environmental Science, Bremen, Germany
Université Catholique de Louvain, Belgium
Volume Title: Geology (Boulder)
Source: Geology (Boulder), 45(4), p.375-378. Publisher: Geological Society of America (GSA), Boulder, CO, United States. ISSN: 0091-7613 CODEN: GLGYBA
Note: In English. GSA Data Repository item 2017107. 30 refs.; illus.
Summary: Earth's climate has undergone different intervals of gradual change as well as abrupt shifts between climate states. Here we aim to characterize the corresponding changes in climate response to astronomical forcing in the icehouse portion of the Cenozoic, from the latest Eocene to the present. As a tool, we use a 35-m.y.-long δ18Obenthic record compiled from different high-resolution benthic isotope records spliced together (what we refer to as a megasplice). We analyze the climate response to astronomical forcing during four 800-k.y.-long time windows. During the mid-Miocene Climatic Optimum (ca. 15.5 Ma), global climate variability was mainly dependent on Southern Hemisphere summer insolation, amplified by a dynamic Antarctic ice sheet; 2.5 m.y. later, relatively warm global climate states occurred during maxima in both Southern Hemisphere and Northern Hemisphere summer insolation. At that point, the Antarctic ice sheet grew too big to pulse on the beat of precession, and the Southern Hemisphere lost its overwhelming influence on the global climate state. Likewise, we juxtapose response regimes of the Miocene (ca. 19 Ma) and Oligocene (ca. 25.5 Ma) warming periods. Despite the similarity in δ18Obenthic values and variability, we find different responses to precession forcing. While Miocene warmth occurs during summer insolation maxima in both hemispheres, Oligocene global warmth is consistently triggered when Earth reaches perihelion in the Northern Hemisphere summer. This pattern is in accordance with previously published paleoclimate modeling results, and suggests an amplifying role for Northern Hemisphere sea ice.
Year of Publication: 2017
Research Program: IODP Integrated Ocean Drilling Program
ODP Ocean Drilling Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Atlantic Ocean; Ceara Rise; Cenozoic; Chemostratigraphy; Climate change; Climate forcing; Cores; East Pacific; Eccentricity; Equatorial Atlantic; Equatorial Pacific; Expedition 321; Expeditions 320/321; IODP Site U1337; IODP Site U1338; Integrated Ocean Drilling Program; Isotope ratios; Isotopes; Leg 154; Leg 162; Leg 177; Leg 184; Leg 199; Leg 208; Marine sediments; North Atlantic; North Pacific; Northeast Pacific; Northern Hemisphere; Northwest Pacific; O-18/O-16; ODP Site 1090; ODP Site 1146; ODP Site 1218; ODP Site 1264; ODP Site 1267; ODP Site 926; ODP Site 982; Ocean Drilling Program; Orbital forcing; Oxygen; Pacific Ocean; Paleoclimatology; Paleotemperature; Precession; Quaternary; Rockall Bank; Sediments; South Atlantic; South China Sea; Southern Hemisphere; Stable isotopes; Tertiary; Walvis Ridge; West Pacific
Coordinates: S280600 S280600 E0014300 E0014200
S283200 S283200 E0025100 E0025100
N192724 N192724 E1161622 E1161622
Record ID: 2017025966
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