Maastrichtian ocean-climate evolution; a view from the tropical Pacific

Author(s): Frank, Tracy D.; Schroeder, Eric J.
Author Affiliation(s): Primary:
University of Nebraska, Department of Geosciences, Lincoln, NE, United States
Volume Title: Geological Society of America, South-Central Section, 41st annual meeting; Geological Society of America, North-Central Section, 41st annual meeting
Source: Abstracts with Programs - Geological Society of America, 39(3), p.72; Geological Society of America, South-Central Section, 41st annual meeting; Geological Society of America, North-Central Section, 41st annual meeting, Lawrence, KS, April 11-13, 2007. Publisher: Geological Society of America (GSA), Boulder, CO, United States. ISSN: 0016-7592 CODEN: GAAPBC
Note: In English
Summary: Well-preserved, Maastrichtian sections recovered from four sites (1209-1212) during Ocean Drilling Program (ODP) Leg 198 to Shatsky Rise in the northwest Pacific provide insight into widespread oceanographic, biotic, and climatic changes that occurred during latest Cretaceous time. Low-resolution isotopic records from these sites have revealed temporal changes in the vertical structure of the water column and the character of water masses that bathed the rise. These data indicated that during the earliest Maastrichtian, Shatsky Rise lay within a relatively warm, well-oxygenated intermediate water mass that originated in the North Pacific. By late Maastrichtian time, however, this warmer water mass had been displaced by a cooler water mass that originated in the Southern Ocean. The present study uses high-resolution isotopic records derived from benthic foraminifera to examine in detail the transition between early and late Maastrichtian circulation modes. The mid-Maastrichtian transition is manifest in the sedimentary record as a prominent 1 to 2-m-thick horizon over shallow portions of Shatsky Rise, which contains a series of layers containing large shell fragments of Inoceramus, a wide-ranging bivalve. High-resolution, isotopic records through this interval suggest that the inoceramids flourished during a brief time when a warm, saline intermediate water mass, possibly from the Western Tethys, moved over the rise. The last occurrence of inoceramids at Shatsky Rise coincides with the withdrawal of this warmer water mass and, on a broader scale, with the global extinction of the inoceramid bivalves and other significant ecological and climatic changes. Results implicate changes in the sources and distribution patterns of intermediate water masses as a major driver for latest Cretaceous global change.
Year of Publication: 2007
Research Program: ODP Ocean Drilling Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Cretaceous; Leg 198; Maestrichtian; Mesozoic; North Pacific; Northwest Pacific; ODP Site 1209; ODP Site 1210; ODP Site 1211; ODP Site 1212; Ocean Drilling Program; Ocean circulation; Pacific Ocean; Paleo-oceanography; Paleoclimatology; Senonian; Shatsky Rise; Tropical environment; Upper Cretaceous; West Pacific
Coordinates: N320000 N320000 E1575100 E1575100
N322700 N322700 E1574300 E1574300
Record ID: 2007111166
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States