Paleobiogeographic Evolution of Shallow-Water Organisms from the Aptian to the Eocene in the Western Pacific

Abstract

Shallow-water organisms recovered from drilling four guyots in the western Pacific (from the southern Marshall Islands to the Japanese Seamounts) allow the recognition of changes in bioprovinces through time. The Tethyan low-latitude bioprovince characterizes the early Aptian worldwide. In the late Albian, however, shallow-water floral and f aunal assemblages from the drilled guyots, although predominantly composed of cosmopolitan forms, yielded few elements with an areal distribution more restricted to either the Caribbean-central American region or the Mediterranean, suggesting that two bioprovinces had already differentiated at low latitude at that time. During the late Campanian-Maastrichtian, the guyots' area was under the influence of the Caribbean bioprovince, but foraminifer assemblages also include some Mediterranean elements, suggesting that colonization occurred both westward and eastward. In the latest Paleocene-early middle Eocene, the direction of colonization reversed, with prevalent migration from the Mediterranean toward the Pacific.

First record of an Early Barremian caprinid rudist from Japan – implications for the palaeobiogeography of the Caprinidae (Bivalvia)

“…In this context, the presence of caprinuloideine rudists in the Central Pacific has attracted attention in recent palaeobiogeographic studies of the Pacific (e.g. Premoli Silva et al . 1995; Chartrousse and Masse 1998 a ; Skelton et al .…”

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“…In addition, nummulitic limestones have been dredged from guyots in the Louisville Seamount Trail, indicating the possible presence of Eocene shallow-water reefs in the high-to mid-latitude Pacific (Lonsdale, 1988). The timing of reef formation, and eventually the drowning of such carbonate banks, is of considerable interest because it provides evidence from the southeast Pacific for the expansion of tropical climates during past warm periods (Adams, 1967(Adams, , 1983Premoli Silva et al, 1995;Huber et al, 1995;Wilson et al, 1998;Jenkyns and Wilson, 1999). These sediments may provide a unique data set, adding to the very sparse paleoclimate record in the South Pacific at such high southern-lati-tude sites (Corfield and Cartlidge, 1992;Corfield and Norris, 1996;Barrera and Savin, 1999;Norris et al, 2001).…”

“…It therefore might provide fundamental constraints on the ancient seasurface temperatures and climate transitions in the greenhouse interval that are characteristic of this time period. Paleolatitudes, timing of formation, and eventually the drowning of such carbonate banks may provide evidence for a temperate climate during these past warm periods at high latitudes in the southern Pacific Ocean, where paleoclimate data are mostly lacking (Premoli Silva et al, 1995;Wilson et al, 1998;Jenkyns and Wilson, 1999).…”

Expedition 330 summary

“…The fossil records can be compared with the 40 Ar/ 39 Ar radiometric age dates measured on basement samples. The timing of reef formation, and eventually the drowning of such carbonate banks, is of considerable interest because it provides evidence from the southeast Pacific for the expansion of tropical climates during past warm periods (Adams, 1967(Adams, , 1983Premoli Silva et al, 1995;Huber et al, 1995;Wilson et al, 1998;Jenkyns and Wilson, 1999). These sediments may provide a unique data set, adding to the very sparse paleoclimate record in the South Pacific at such high southern-latitude sites (Corfield and Cartlidge, 1992;Corfield and Norris, 1996;Barrera and Savin, 1999;Norris et al, 2001).…”

“…It therefore might provide fundamental constraints on the ancient sea-surface temperatures and climate transitions in the greenhouse interval that are characteristic of this time period. Paleolatitudes, timing of formation, and eventually the drowning of such carbonate banks may provide evidence for a temperate climate during past warm periods at high latitudes in the southern Pacific Ocean, where paleoclimate data are mostly lacking (Premoli Silva et al, 1995;Wilson et al, 1998;Jenkyns and Wilson, 1999).…”