Week 2 Recap

Simon, Chris, and I met with Jim Ingle to get his opinion on our samples, particularly the corals. He identified three of our corals as a shallow water variety called Balanophyllia elegans. He pointed out that two of these corals were in pristine shape, likely indicating that they are very young. He suggested that the rest of our corals were not actually corals but instead the calcareous deposits of an algal mat. While this means they are worse candidates than corals for U-series dating, it still may be possible to date these using an isochron method, as explored in the papers I read during week 1.

During week 1, I removed samples of mud and sand from every bagged sample. This week I dried these samples in Mitchell A55 and sifted them through a 150 micron sieve. We will meet with Jim Ingle again during week 3, and he will look at the forams in the samples I sifted in order to estimate water depth at the time of deposition.

I finished working through the cores that Chris obtained from USC's core repository. The majority of the cores we were looking for were missing, and most cores that we did have were poor in carbonates. However, three of these cores turned up substantial carbonate samples. Additionally, many of these cores had foram-rich sand, which we will also show to Jim Ingle next week.

I started going through the cores we collected earlier in June. I broke open the cores that displayed no strata or had very little material. These I sorted through for shells or corals. No corals were present, however I found several large shells in different cores. These cores were placed in bags and returned to cold storage in Mitchell. We may dry them in A55 and pick out shell fragments, though that may not be necessary.

On Monday, Chris and I will go to the USGS core lab in Menlo Park to split the remaining cores. After that I will characterize the material and have a better idea of what samples I can move forward with dating.

I skipped town on Friday and headed home for a long Independence Day weekend.

I read and took notes on the following papers:

Osmond, J.K., May, J.P., and Tanner, W.F., 1970, Age of the Cape Kennedy barrier-and-lagoon complex: Journal of Geophysical Research–Planets (1991–2012), v. 75, p. 469–479.

Kaufman, A., Broecker, W.S., Ku, T.L., and Thurber, D.L., 1971, The status of U-series methods of mollusk dating: Geochimica et Cosmochimica Acta, v. 35, p. 1155-1183.