Collection of seismic reflection data in Lake Michigan to define the stratigraphy and sediment character of the deposits below the lake floor. The seismic reflection data was used to choose final core locations for the second leg of the cruise. These cores will be used to develop a closely dated record of sedimentation and paleoenviromental conditions in the lake. The cores and the seismic reflection data together will be used to determine the history of lake-level fluctuations over the last several thousand years.
Location
Lake Michigan, Great Lakes, United States, North America;
Summary
The cruise was generally successful although plagued with mobilization problems and some weather difficulties. Two storms, one of which was the remains of Hurricane Gilbert, forced our return to port. Mobilization for the seismic leg (Leg 1) took 3 days instead of the allotted 2, and the coring mobilization (Leg 2) took 6 days instead of the allotted 2. Nevertheless, a total of 950 km of seismic reflection profiles were collected and 13 cores (6 piston and 7 vibracores) were obtained. Analysis of the seismic reflection profiles and cores should provide sufficient data to begin to decipher the history of changes in lake level in Lake Michigan over the last several thousand years and the lake's response to those changes.
Comments
This cruise was Leg 2 of two legs: 88014 (Leg 1, Seismics) and 88015 (Leg 2, Seismics and Coring). Original Center People field contained: Dave Foster, Bob Oldale, Larry Poppe, Peter Popenoe, Ken Parolski (Technician), Barry Irwin (Navigation specialist).
Project = Lake Level and Sed. History (LLASH), Lake Level and Sed. History (LLASH)
Information from Foghorn: Seismic Reflection (3.5 kHz): ORE transducer, ORE 140 transceiver, EPC 3200 graphic recorder; Seismic Reflection(boomer): Huntec DTS fish, Benthos winch, Huntec acoustic reflectivity unit, ORE GeoPulse 5210A amplifier/filter, Benthos AQ-4 10-element hydrophone streamer, Datum 9300 time-code generator, BNC 7010 digital delay generator, EPC 312 record annotator, EPC 4800 graphic recorder, Hewlett-Parkard 3968A 8-track analog tape recorder;Navigation: Megapulse Accufix 500 LORAN-C receiver, IBM-PC control program (Irwin) and printer/disk storage;
Chief Scientist's cruise report including personnel, purpose, equipment and equipment performance, brief cruise summary, and table of start and end of lines. This information covers 2 field activities (1988-014-FA and 1088-015-FA)
