| Paleomagnetic and rock magnetic analyses were conducted on Ordovician specimens collected from two wells in the Dover Field and a reference core (OGS-83) in southwestern Ontario, for comparison to the results of Garner (2006) in the Hillman/Goldsmith-Lakeshore Fields (HGLF). Single domain (SD) and pseudosingle domain (PSD) magnetite grains were observed in the Dover Field, differing from the SD and PSD pyrrhotite and magnetite with minor hematite content in the HGLF. Inclination-only analysis was used to determine the paleodirections of the wells for the Dover Field and the reference core OGS-83. Well A samples (dolomite) had a mean of I-1.0° +3.0/-3.4° (N=3, k=378.3), while two segments from Well B (limestone) had means of I=--15.8° +3.8°/-3.6° (k=83.0) and I=-8.3° +5.0°/-5.4° (k=46.2). The paleolatitudinal arc produced from Well A intercepted the Late Pennsylvanian and Permian sections of the reference apparent polar wander path, while the Well B arc intercepted the Pennsylvanian or the Triassic, and the OGS-83 arc intercepted the Permian. The Dover and HGLF (Garner, 2006) results differed, suggesting that the diagenetic history of the areas were not the same. Isotopic analysis suggested a shallower burial depth and lower temperature of dolomite formation in the Dover Field compared to HGLF.; Rock magnetic properties were examined before and after standard porosity and permeability analysis (PPA) to determine what affect, if any, there was on the magnetic minerals of samples from this study. Due to the inability of partial anhysteretic magnetization (pARM) analysis to remove an induced magnetization which was acquired either outside of the laboratory or during saturation isothermal magnetization (SIRM) analysis, this technique did not provide useful results. The PPA did have an affect on the SIRM data; the SIAM values and 100/SIRM, 200/SIRM, 300/SIRM and 400/SIRM values increased for nearly all samples suggesting that the PPA increased either the concentration of grain size of the magnetic minerals. No discernable patterns in the pARM and SIRM changes related to lithology or similar factors were established. Further study on a larger number of samples may be required to determine if a consistent pattern exists. |
