APPENDIX F 

 SEDIMENT THICKNESS DATA FROM SEISMIC RECORDS 



Seismic velocities: 



water 



V = 1.54 meters per millisecond 



postglacial sediments v = 1.3 meters per millisecond 



till V = 1.8 meters per millisecond 



Water depth is survey water depth (about 174.3 meters), which is 1 meter above 

 low water datum (IGLD, 1955). 



a. Postglacial sediment and till thicknesses were measured at two con- 

 fidence levels. Those followed by an "a" (the first confidence 

 level) are those in which the reflector was well defined on the 

 seismic record; unmarked thicknesses are those in which the reflec- 

 tor was not well defined on the seismic record yet whose position 

 could be reasonably well inferred from the overall geologic setting 

 and character of the reflector. 



b. The letter "b" indicates thickness data not available because (1) 

 both postglacial sediment and till thicknesses could not be meas- 

 ured because of difficulty in interpreting the seismic records 

 (in this case water depth was not measured) , or (2) the seismic 

 reflection record for the fix is missing. 



All thicknesses in meters 



T = trace of material, <0.5 meter, but enough to change surface echo 

 character. 



X = thickness not measurable because of lack of lower reflector. 



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