title: Pliocene cooling enhanced by flow of low-salinity Bering Sea water to the Arctic Ocean.
abstract: Warming of high northern latitudes in the Pliocene (5.33-2.58 Myr ago) has been linked to the closure of the Central American Seaway and intensification of North Atlantic Deep Water. Subsequent cooling in the late Pliocene may be related to the effects of freshwater input from the Arctic Ocean via the Bering Strait, disrupting North Atlantic Deep Water formation and enhancing sea ice formation. However, the timing of Arctic freshening has not been defined. Here we present neodymium and lead isotope records of detrital sediment from the Bering Sea for the past 4.3 million years. Isotopic data suggest the presence of Alaskan glaciers as far back as 4.2 Myr ago, while diatom and C37:4 alkenone records show a long-term trend towards colder and fresher water in the Bering Sea beginning with the M2 glaciation (3.3 Myr ago). We argue that the introduction of low-salinity Bering Sea water to the Arctic Ocean by 3.3 Myr ago preconditioned the climate system for global cooling.
authors.affiliation: 1] Department of Geological Sciences, University of Florida, Gainesville, Florida 32611, USA [2] Graduate School of Environmental Studies, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan.
authors.forename: Keiji
authors.initials: K
authors.lastname: Horikawa
authors.affiliation: Department of Geological Sciences, University of Florida, Gainesville, Florida 32611, USA.
authors.forename: Ellen E
authors.initials: EE
authors.lastname: Martin
authors.affiliation: Department of Geological Sciences, University of Florida, Gainesville, Florida 32611, USA.
authors.forename: Chandranath
authors.initials: C
authors.lastname: Basak
authors.affiliation: Japan Agency for Marine-Earth Science and Technology, 2-15 Natsushima-cho, Yokosuka 237-0061, Japan.
authors.forename: Jonaotaro
authors.initials: J
authors.lastname: Onodera
authors.affiliation: Institute of Low Temperature Science, Hokkaido University, N19W8, Kita-ku, Sapporo, Hokkaido 060-0819, Japan.
authors.forename: Osamu
authors.initials: O
authors.lastname: Seki
authors.affiliation: Japan Agency for Marine-Earth Science and Technology, 2-15 Natsushima-cho, Yokosuka 237-0061, Japan.
authors.forename: Tatsuhiko
authors.initials: T
authors.lastname: Sakamoto
authors.affiliation: Center for Advanced Marine Core Research, Kochi University, B200 Monobe, Nankoku 783-8502, Japan.
authors.forename: Minoru
authors.initials: M
authors.lastname: Ikehara
authors.affiliation: Japan Agency for Marine-Earth Science and Technology, 2-15 Natsushima-cho, Yokosuka 237-0061, Japan.
authors.forename: Saburo
authors.initials: S
authors.lastname: Sakai
authors.affiliation: Institute of Low Temperature Science, Hokkaido University, N19W8, Kita-ku, Sapporo, Hokkaido 060-0819, Japan.
authors.forename: Kimitaka
authors.initials: K
authors.lastname: Kawamura