(Table T1) Correlations between marker beds and drill holes for ODP Leg 171B sites

More than 50 discrete volcanic ash layers were recovered at the five drill sites of the Blake Nose depth transect (Leg 171B, western central Atlantic). The majority of these ash layers are intercalated with Eocene hemipelagic sediments with a pronounced frequency maximum in the upper Eocene. Several...

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Bibliographic Details
Main Authors: Pletsch, Thomas, Reicherter, Klaus
Format: Dataset
Language:English
Published: PANGAEA 2001
Subjects:
171-1049
171-1050
171-1051
171-1052
171-1053
Blake Nose
North Atlantic Ocean
Carolina Slope
Code
COMPCORE
Composite Core
Depth
composite
composite error
reference
sediment/rock
DSDP/ODP/IODP sample designation
Event label
Joides Resolution
Leg171B
Ocean Drilling Program
ODP
Sample code/label
Sample code/label 2
Sample comment
North Atlantic
Online Access:https://doi.pangaea.de/10.1594/PANGAEA.788231
https://doi.org/10.1594/PANGAEA.788231
Description
Summary:More than 50 discrete volcanic ash layers were recovered at the five drill sites of the Blake Nose depth transect (Leg 171B, western central Atlantic). The majority of these ash layers are intercalated with Eocene hemipelagic sediments with a pronounced frequency maximum in the upper Eocene. Several ash layers appear to be deposited from volcanic fallout with little or no indication of secondary remobilization. They provide excellent stratigraphic markers for a correlation of the Leg 171B drill sites. Other ash layers were probably redeposited from volcaniclastic-rich turbidity currents, but they still represent geologically instantaneous events that can be used in stratigraphic correlation between adjacent drill holes. Additional nonvolcanic marker beds, like the suspect late Eocene impact event layer, were included in our hole-to-hole correlations. Stratigraphic and downcore positions of marker beds were compiled and plotted against existing composite depth records that were constructed to guide high-resolution sampling. Comparison of our correlation with the spliced composite sections of each drill site reveals several minor and some major discrepancies. These may result from drilling distortion or missing sections, from the lack of unambiguous criteria for the synchronism of ash layers, or from the systematic exclusion of marker-bed data in the construction of the spliced record. Integration of both correlation approaches will help eliminate most of the observed discrepancies.

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