Wednesday, November 2, 2011

Thoughts on Manis Mastodon and Western Washington

Lots of buzz regarding the pre-Clovis spear point embedded in the rib of a mastodon found south of Sequim, Washington. The age of this mastodon is an important determination regarding the presence of man in North America at 13,800 years ago. People were hunting mastodons on the Olympic Peninsula prior to glacial ice fully retreating from northern Washington State. - Pre-Clovis Mastodon Hunting

The discovery was not a new find. Emanuel Manis found the mastodon bones while digging a pond with a backhoe on his property in near Sequim, Washington in 1977. Some very great archeology has been found with backhoes and Mr. Manis took his discovery seriously. He made some phone calls and soon had an archeology dig on his property led by Carl Gustafson of Washington State University. Mastodons fossils are not a rare occurrence in western Washington; however, despite all my traverses on steep eroding slopes I have thus far never had the good fortune to find one.

Gustafson took the find seriously because the bones were within a wetland area and provided an excellent opportunity via pollen counts to get a handle on the climate conditions. What is more, the site had a layer of volcanic ash so a relative date could be determined. Gustafson then made the astonishing discovery of a bone spear point embedded within a rib of the animal. Furthermore Gustafson estimated that the animal lived 14,000 years ago.

Archaeologists are a skeptical and cautious bunch and the site fell into that enigma category of a very old human site but of uncertain age. But new advances in technology and tools for dating have been developed and it turns out Gustafson was real close on his estimate. A team of scientists dated the mastodon with the bone spear point at 13,800 years old (see above link to Science Magazine article (abstract only unless you are a Science subscriber)).

What was western Washington like 13,800 years ago. Apparently Sequim was a fairly dry place at that time just as it is today only drier. The wetland area had pollen indicative of a brush covered landscape and included cactus. This is consistent with western Washington being drier at the late stages of the ice age.

But a very tantalizing aspect of this site is the fact that people were on the Olympic Peninsula so soon after the ice retreated from the area. In fact there was still substantial glacial ice in the northwest corner of Washington State at that time. It is very likely that there were ice bergs floating about the Strait of Juan de Fuca.
An intriguing feature of the coastal areas near Sequim and Puget Sound is that the shoreline was different than today.

Image from Ralf Haugerud and Harvey Greenburg (2000)
 puget-sound-13980-bc (includes link to clip)

Note that Puget Sound was bigger 13,000 years ago. The reason was that the mass of glacial ice had pressed the local surface of the earth downward. As the ice retreated, the pressed down areas were flooded with water. Rebound lifted many areas out of the water over the the next few thousand years. Hence, shoreline locations are substantially different today compared to the time of the Manis mastodon hunt.

The presence of humans in this area so soon after the glacial ice retreated raises some other very interesting question about the first human settlers. Is it possible that the first arrivals to western Washington did not arrive via land but by water. If they did, their coastal camp sites or settlements are now deeply submerged as the outer coast, where there was no glacial ice, sea levels were much lower during the ice age.

Another fascinating question: Were people in eastern Washington at the same time. If humans were present some of them had eye witness views of the huge Missoula floods. One book I read on the floods speculated on just that and in that speculative account things did not work out so well for the witnesses.

But finally the confirmation that humans were present in western Washington before the ice age ended means that the post ice-age ecosystem and landscape evolution in at least western Washington was influenced by the presence of man from the very beginning. The ecosystems evolved with man. If the first people had not arrived so early, perhaps western Washington would be a bit different today than it is. Perhaps mastodons and giant bison (there is a likely very old bison butcher site on Orcas Island) would have still been meandering about the lowlands of western Washington for a longer period.

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