Computer-Generated Late Cretaceous Oceanic Circulation
Model
Memorie K. Yasuda, Eric J. Barron, Robert G. Douglas
Simulations of Campanian and present-day ocean circulation were generated
using an adapted version of the numerical
ocean
model
created by Semtner.
Model
input for the Campanian simulation includes paleogeography provided by Barron et
al; paleodepths based on the Sclater-Francheteau age-depth relationship; and
atmospheric parameters (sea-surface temperature, meridianal and latitudinal wind
stress, precipitation, and evaporation) which are derived from a mean annual
version of the National Center for Atmospheric Research spectral general
circulation
model
.
The model
has a horizontal resolution of 5° latitude by 5° longitude and
recognizes the presence of up to four vertical ocean grid boxes with thicknesses
of 50, 450, 1,500, and 2,000 m. The
model
is driven by atmospheric forcing and
uses the
numerical
scheme of Bryan based on primitive equations for a
hydrostatic Boussinesq ocean with a rigid lid.
The model
produces global plots at each vertical ocean level for temperature,
salinity, u-velocity, v-velocity, current vector, and stream function. Plots are
also produced for heat flux, ice thickness, and vertical velocity. With this
output, we focus on the problems of locating bottom-water sources and areas of
high surface water productivity. The Campanian was selected since the different
distribution of continents and oceans resulted in a period of relatively warm
global temperatures with the existence of marginal seas in evaporative zones
providing the best case for the possibility of high-salinity, low-latitude
bottom water. In addition, we address the practical problem of locating
potential upwelling areas since the close link to high surface water
productivity is a major contr buting factor to the deposition of organic-rich
sediments.
AAPG Search and Discovery Article #91038©1987 AAPG Annual Convention, Los Angeles, California, June 7-10, 1987.