Stable isotropic evidence for relative and eustatic sea-level changes in Eocence to Oligocene carbonates, Baldwin County, Alabama: discussion

Article Abstract:

The accuracy of the biostratigraphic determination of the boundary and the age of interval at the Bay Minette borehole presented by Baum et al. in 1994 is discussed. Their paper presents the boundary as separating upper middle Eocene Lisbon Formation from uppermost middle to lower upper Eocene Gosport and Moodys Branch Formations. However, the technique used cannot assure accuracy because it is not applicable to shallow-water marine sequences. A more accurate indicator, the fossil groups of rapid evolution, shows that the sequence is middle Eocene, Lisbon Formation, not Gosport and lower Moodys Branch Formations.

Geology, Stratigraphic, Stratigraphy, Alabama, Sea level, Paleoceanography, Paleogene period

---

Discussion

Article Abstract:

McKee and Conrad's suggestion that there was a magmatic episode in the Northern part of the White Mountains, CA, during Late Cretaceous Period as indicated by biotite Ar-Ar dates for granitic rocks found in the region is analyzed. McKee and Conrad estimated the McAfee Creek pluton, one of the Cretaceous intrusions, to be 83.6 Ma based on a biotite age. However, this intrusion has a U-Pb zircon age of 100 plus or minus 1 Ma which means that nearly all of the intrusions in the White Mountains were emplaced approximately 15 m.y. before the Cretaceous time.

Natural history, Sierra Nevada (United States), Granite, White Mountains (New Hampshire), Intrusions (Geology)

---

Geological reasoning: geology as an interpretive and historical science: discussion

Article Abstract:

fff.

Geology

Similar abstracts:

• Abstracts: Paleomagnetic evidence for en echelon crustal extension and crustal rotations in western Montana and Idaho. Implications of paleomagnetic data on Miocene extension near a major accommodation zone in the Basin and Range province, northwestern Arizona and southern Nevada
• Abstracts: Nd isotopic evidence for juvenile crust in the Carolina terrane, southern Appalachians. U-Pb isotopic evidence for the accretion of different crustal blocks to form the Lewisian Complex of northwest Scotland
• Abstracts: Serving science and society: lessons from large-scale atmospheric science programs. Report discusses use of units in atmospheric chemistry
• Abstracts: Internal fabric and strike-slip emplacement of the Pan-African granite of Solli Hills, northern Nigeria. Structural evolution of the northern Los Angeles basin, California, based on growth strata
• Abstracts: Toward a scientific centered climate monitoring system. Assessing the health impacts of climate change

This website is not affiliated with document authors or copyright owners. This page is provided for informational purposes only. Unintentional errors are possible.