Coleoptera fossils: their potential value for dating and correlation of late Cenozoic sediments

Abstract

Coleoptera (beetle) fossils play an important role in paleoecological research, but as yet have contributed little information bearing on dating and correlation. The reason for this is that most Quaternary fossils represent extant species, precluding the evolutionary approach to dating, while the rarity and poor preservation of Tertiary beetle fossils, many of which are from extinct species, seriously limit their application to stratigraphic studies.Tertiary beetle fossils recently discovered in Arctic Canada and Alaska are both well preserved and abundant. Most of them represent extinct species that are closely related to living forms, hence they have potential stratigraphic value. In one case treated herein comparison of fossils of an Alaskan Tertiary species with those of a related species from the Beaufort Formation on Meighen Island (Canadian Arctic Archipelago) implies that the latter sediments were deposited less than 5.7 Ma ago. However, this conclusion requires testing because it is at odds with the date on Meighen Island exposures reached by study of fossil plants. I submit that further study of the insect fossils from the Beaufort Formation and other late Tertiary sites will help resolve such problems of dating and correlation.Quaternary beetle fossils have stratigraphic value even though fragments of that age represent for the most part only existing species. For example, it has been shown that late Pleistocene fossils of stenothermal Coleoptera species can provide a sensitive record of climatic change, and thus such fossils may be used for site to site correlation in areas where climatic history is well documented. In exceptional cases beetle fossils appear to provide a more accurate basis for correlation than even fossil pollen.