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MAGNETOSTRATIGRAPHY SUSCEPTIBILITY USED FOR HIGH-RESOLUTION CORRELATION AMONG SANTONIAN (UPPER CRETACEOUS) MARINE SEDIMENTARY SEQUENCES IN THE U.S. WESTERN INTERIOR SEAWAY AND THE WESTERN SINAI PENINSULA, EGYPT

مؤلف البحث
BROOKS B. ELLWOOD, AZIZ KAFAFY, AHMED KASSAB, ABDELAZIZ ABDELDAYEM, NAGEH OBAIDALLA, AND
RICHARD W. HOWE AND PAUL SIKORA
ملخص البحث

Magnetic susceptibility (MS) measurements of marine rocks provide an underutilized but powerful high-resolution tool in
stratigraphy. In ideal circumstances and when combined with other stratigraphic techniques, the method can yield resolution to 10,000
years or less. This paper applies the MS method to solving a Cretaceous global correlation problem. Because of the active global processes
that drove significant evolutionary changes during this time, the Upper Cretaceous is important in Earth history. However, correlations
among geological sequences are difficult, in part because Earth’s magnetic polarity was essentially non-varying from the Aptian to the
Santonian. Here we present high-resolution correlations for Upper Cretaceous marine sedimentary successions spanning all or part of the
Santonian Stage from the Western Interior Seaway (U.S.A.) and the Western Sinai Peninsula (Egypt). To do this we have integrated the
results of magnetic susceptibility (MS) measurements of unoriented samples from lithified marine rocks (in outcrop and from core) and
biostratigraphic data sets from these sequences. In this study a MS zonation for the Santonian Stage has been developed and graphic
comparison has been used for correlation. In the main, correlation between the U.S. and Egyptian sequences is excellent. Third order T/
R cycles (> 100 ka) observed in this high-resolution data set for the Santonian Stage indicate significant similarities between the U.S. and
Egyptian sections and allow correlation among sequences. We interpret these correlations to result from cyclicities caused by climatecontrolled
continental erosion and deposition of detrital components, mainly clay, in the marine realm. Second-order cycles (> 1 Myr), are
also observed in these data sets but show distinctive differences between the U.S. and Egyptian sequences. We interpret these second-order
differences to result from local synsedimentary tectonic controls on sediment erosion and deposition. Also observed are two distinct, shortterm
MS marker events that can be correlated globally.

قسم البحث
مجلة البحث
Application of Modern Stratigraphic Techniques: Theory and Case Histories
SEPM Special Publication
المشارك في البحث
الناشر
SEPM (Society for Sedimentary Geology), ISBN 978-1-56576-199-5
تصنيف البحث
1
عدد البحث
No. 94
موقع البحث
NULL
سنة البحث
2010
صفحات البحث
p. 155–166