I have been trying to find a dataset for the earth's long-term historical temperature record.
I have seen a few charts like this one from wikipedia.
Is there an open dataset with this information? If it exists, where can it be found?
The Zachos et al. article has supplemental data section, but there are no actual datasets in this section, only sources for ΔO-18 and ΔC-13 isotopic data. The article itself says that the temperature estimates are given for an ice-free world ocean. If you want to cite the data from Figure 2 in the article without all the caveats (and then some) of the original, your readers will be either fooled or offended.
A sample caveat from the supplement:
Sampling Biases: One of the limitations on reconstructing long-term secular variations is the highly uneven distribution of deep-sea stable isotope data in both space and in time. The global signal for some key intervals is based on data from just a few records (emphasis mine - DH). In general, these spatial biases increase with age, moving toward the Atlantic, and shallower water depths. In other words, the Pacific, and abyssal portions of the oceans tend to be under-represented in existing stable isotope records. These biases do not pose a problem for our temperature/ice-volume reconstruction of the late Neogene oceans which were thermally homogeneous. Such biases, however, are a concern for establishing the mean climate-state of some "warmer" time intervals when the thermal gradients within the deep-sea were greater.