Eustasy Determination from Borehole Data, Onshore New Jersey: New Boreholes and New Porosity Estimates
Date of Award
Master of Science
Geological and Environmental Sciences
Dr. Michelle A. Kominz
Dr. William B. Harrison III
Dr. Dave Barnes
Masters Thesis-Open Access
Backstripping analysis of detailed stratigraphic data from the Bass River and Ancora boreholes on the New Jersey Coastal Plain (Ocean Drilling Project Leg 17 4AX) was conducted to test and refine previous eustatic estimates (Kominz et al., 1998) and provide new Upper Cretaceous estimates. Porositydepth relationships required by the backstripping method were estimated to supplement those from the Cost B-2 well (Rhodehamel, 1977). Sand and mud porosity at shallow depths (<500 m) obtained here are higher than was seen at the Cost B-2 well.
The Bass River and Ancora boreholes targeted older sequences of the Upper Cretaceous to Paleocene. This new data allow for more accurate estimate of the magnitude of long-term sea-level change and provide new information on older (Cretaceous) short-term signals. Eustatic amplitudes varied by as much as 50 m between Cretaceous sequences, suggesting a maximum amplitude of 3rd order sea-level change of about 90 m. Results from Paleocene and younger strata suggest a long-term (108 - 107y) eustatic fall of ≈100 m and superimposed 3rdorder (0.5 - 3 m.y.) eustatic changes of less than ≈70 m. Sea-level amplitudes and durations were comparable when sequences are represented at multiple boreholes. This suggests that the resultant curves are an approximation of eustasy.
Van Sickel, William Alan, "Eustasy Determination from Borehole Data, Onshore New Jersey: New Boreholes and New Porosity Estimates" (2000). Masters Theses. 4420.