An integrated paleomagnetic, magnetic fabric, and petrographic study of two cores (EC: oriented; DB: unoriented) in the Devonian Marcellus Formation from the Plateau Province (PA) indicates the presence of chemical remanent magnetizations (CRMs) and extensive diagenetic alteration. Anisotropy of magnetic susceptibility results indicate a predominately oblate fabric. Some specimens contain a prolate fabric that is interpreted as diagenetically altered. A well-developed viscous magnetization, possibly contaminated by a drilling induced component, is not present in either core, and cannot be used for orientation. An intermediate temperature component with steep down inclinations (ITN) is removed in both cores below ~ 300°C. Specimens in DB also contain a component with steep up inclinations (ITR) that is removed between 300 and 440°C. The ITN is interpreted to reside in magnetite and/or possibly pyrrhotite, and the ITR resides in magnetite. The ITN could be a reversal of ITR, acquired in the Cretaceous to Cenozoic based on a comparison with the expected inclinations. Alternatively, the ITN could be a contaminated by a Brunhes viscous magnetization. Specimens from both cores contain a characteristic remanent magnetization (ChRM) with shallow inclinations that is removed by 500°C in DB and 460°C in EC, and is interpreted to reside in magnetite. The DB ChRM has an inclination of -9.0°, which corresponds to a range of ages between 310-225 Ma based on the expected inclinations. The ChRM in EC has streaked declinations, which may have been caused by core barrel rotation. Shallow inclinations (- 3.7°) in this core suggest a range of acquisition from 305-230 Ma. Rock magnetic data are consistent with the presence of magnetite but provide conflicting evidence for pyrrhotite. The ChRM in DB is interpreted as a CRM whereas the ChRM in EC could be thermoviscous in origin. Diagenetic studies indicate a complex paragenesis with authigenic minerals such as barite, sphalerite, baroque dolomite, and sylvite suggestive of alteration by external fluids. The presence of the CRM in highly altered zones suggests it is related to alteration by external fluids, although its presence in other facies suggests that burial diagenetic processes could also be a cause of remagnetization.
Summary The imaging challenges in the eastern Mediterranean region are being addressed using modern technology combined with valuable geoscience experience. Large seismic datasets with improved presalt imaging allow explorers to form better regional understanding and de-risk targets that were previously difficult to resolve. The area remains a challenge in terms of understanding the tectonics and imaging the subsurface, however the potential is vast in an area that is very well located to markets, so explorers will persist.
ABSTRACT The thermoluminescent characteristics of 15 soil and 73 mineral and rock samples were examined. The soils of widely different chemical types showed wide range of thermoluminescent characteristics. Generally, soils high in lime content showed very high TL. One soil, which was relatively high in free iron content exhibited no TL. The natural TL of soils appeared to be affected by the kinds and amounts of mineral and rock materials present. Since the TL of the different samples even of the same mineral species varied widely, there appeared to be no criterion by which minerals could be identified or classified on the basis of their natural TL. Different lots of samples, however, might be differentiated from each other. Most soils and minerals showed only little, if any, TL below 200°C.
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