Geology topics

Daniel C. Fisher

Publications and source records attributed to Daniel C. Fisher.

4 recordsLinked to original sources

USGS2018

Holen et al. reply

Contrary to our hypothesis that the Cerutti Mastodon (CM) site represents a 130,000-year-old archaeological site, in the accompanying Comment Ferraro et al . argue that the site formed through ‘common’ geological and taphonomic processes. As a source for the cobbles that we interpreted as hammerstones and anvils, they postulate a previously unrecognized alluvial fan, later removed by fluvial winnowing that somehow left our five cobbles, refitting flakes, and fragments of stone, mastodon bone and teeth in place. There is no sedimentological or geomorphic evidence of an alluvial fan, and their scenario leaves unexplained a number of taphonomic features, including the two discrete concentrations in which were found cobbles, refit stones and bones, impact-fractured bones, side-by-side femoral heads and a tusk oriented vertically.

Nature↗

USGS2017

Disparate perspectives on evidence from the Cerutti Mastodon site: A reply to Braje et al.

The Perspective editorial by Braje, T., T. D. Dillehay, J. M. Erlandson, S. M. Fitzpatrick, D. K. Grayson, V. T. Holliday, R. L. Kelly, R. G. Klein, D. J. Meltzer, and T. C. Rick (2017. “Were Hominins in California ∼130,000 Years Ago?” PaleoAmerica 3 (3): 200–202) takes issue with our argument [Holen, S. R., T. A. Deméré, D. C. Fisher, R. Fullagar, J. B. Paces, G. T. Jefferson, J. M. Beeton, et al. (2017. “A 130,000-Year-Old Archaeological Site in Southern California, USA.” Nature 544 (7651): 479–483) that the assemblage of bones and stones at the Cerutti Mastodon (CM) site implicates hominin activity in site formation 130,000 years ago. Braje et al. propose instead that features of the CM site can be better explained by geological or other causes unrelated to ancient human activity. However, we contend that their conclusion reflects an incomplete assessment of our evidence. They further propose a standard of evidence at odds with current practice in the philosophy of science, and misuse a commonly quoted aphorism that “extraordinary claims require extraordinary evidence.”

California↗

USGS2017

Broken bones and hammerstones at the Cerutti Mastodon site: A reply to Haynes

Haynes [2017 “The Cerutti Mastodon.” PaleoAmerica 3 (3): 196–199] criticizes numerous aspects of our analysis of the Cerutti Mastodon (CM) site, but central among his points is the claim that heavy equipment broke the bones and stones that we interpret as evidence of ancient human activity. This notion can be discounted primarily because most of the relevant CM fragments were found coated in thick crusts of pedogenic carbonate clearly showing that breakage occurred thousands of years ago. Haynes also raises questions about site stratigraphy, radiometric dating, and absence of other artifactual evidence. The stratigraphic context of CM bones and rocks is well-defined, and the Pleistocene site stratigraphy remained intact before excavation. Knapped stone tools are not a requirement in bone processing archaeological sites. In the absence of other plausible explanations for the multiple lines of evidence, we maintain that hominins broke the CM bones using stone hammers and anvils.

California↗

USGS2017

A high-elevation, multi-proxy biotic and environmental record of MIS 6-4 from the Ziegler Reservoir fossil site, Snowmass Village, Colorado, USA

In North America, terrestrial records of biodiversity and climate change that span Marine Oxygen Isotope Stage (MIS) 5 are rare. Where found, they provide insight into how the coupling of the ocean–atmosphere system is manifested in biotic and environmental records and how the biosphere responds to climate change. In 2010–2011, construction at Ziegler Reservoir near Snowmass Village, Colorado (USA) revealed a nearly continuous, lacustrine/wetland sedimentary sequence that preserved evidence of past plant communities between ~ 140 and 55 ka, including all of MIS 5. At an elevation of 2705 m, the Ziegler Reservoir fossil site also contained thousands of well-preserved bones of late Pleistocene megafauna, including mastodons, mammoths, ground sloths, horses, camels, deer, bison, black bear, coyotes, and bighorn sheep. In addition, the site contained more than 26,000 bones from at least 30 species of small animals including salamanders, otters, muskrats, minks, rabbits, beavers, frogs, lizards, snakes, fish, and birds. The combination of macro- and micro-vertebrates, invertebrates, terrestrial and aquatic plant macrofossils, a detailed pollen record, and a robust, directly dated stratigraphic framework shows that high-elevation ecosystems in the Rocky Mountains of Colorado are climatically sensitive and varied dramatically throughout MIS 5.

Colorado↗