@article{oai:tohoku.repo.nii.ac.jp:00010731,
 author = {Bandy, Orville L.},
 journal = {Science reports of the Tohoku University. 2nd series, Geology. Special volume = 東北大学理科報告. 地質学},
 month = {May},
 note = {application/pdf, In modern oceans, the tropical isotherm of 20 degrees C, ranges between 20 and 40 degrees N. latitude, depending upon the particular oceanographic conditions at any one locality. Studies of planktonic Foraminifera indicate that there have been two, possibly three, cycles of warming in which the limits of the tropical zone have extended well north of the 40 degree parallel within the Upper Cretaceous-Cenozoic interval. A prominent cycle of warming occurred in the Upper Cretaceous, a second in the later Paleocene and lower Eocene, and a third minor one in the later Eocene. These cycles of warming and cooling are in contradiction to other types of data. The disparity is possibly due to the lack of sampling density for other types of fossil evidence or the greater temperature sensitivity of planktonic Foraminifera., 紀要類(bulletin), 562187 bytes},
 pages = {1--8},
 title = {Planktonic Foraminiferal Criteria for Paleoclimatic Zonation},
 volume = {4},
 year = {1960}
}