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GEOS 211: The Uncovering of Quartz from Submerged Archaeological Sites

The general public often do not associate archaeology with geology. However, they are very much intertwined especially when dealing with lithics, the study of how earth materials were transformed into tools: human artifices. For example, there are specific rocks and minerals, which are today found in a plethora of archaeological sites throughout North America because of their usefulness due to specific properties. We must also take into account that there are certain rocks that are never made into tools. The determining factor whether a rock or mineral is used as a tool is based on its qualities like fracture and hardness.

Recently, research was conducted to search for artifacts in lake sediment beneath the Great Lakes. Looking for artifacts under the lake is challenging due to actually locating the artifacts in the lake sediment. Today, there is growing interest in this area: the drainage of Lake Iroquois exposed sites that date to the Late Archaic period, as well as the earlier Paleoindian. Sonnenburg, Boyce, and Reinhardt produced an alternate approach that would enable the analysis of submerged artifacts that was originally difficult to obtain and understand. The main artifacts observed were microdebitage.

Debitage are the remains from the flaking of tools. Fractures can reveal the process of how the objective piece was made. Microdebitage relates to the smaller fragments that are less than 1mm in length and width. “Experimental studies have shown that production of one stone tool distributes more than one million particles, less than 1mm over a 2-3 meter radius” (Fladmark, 1982). Microdebitage is easily extracted from sediment using methods of sieving and are then identified by its high angularity, presence of conchodial fractures and particle sizes found under light microscope (Sonnenburg, 2011).

Vibracores were taken out of the McIntyre lagoon and specific lithostratigraphic units later categorized the sediment. The sizes of the microdebitage as well as the microfossil analysis were also recorded (Sonnenburg, 2011).  The following criteria were used to identify the microdebitage extracted: high angularity, particle geometry, the presence or lack of conchodial fracture, and grain size larger than the surrounding matrix. By using carbon dating on seeds and wood fragments found in the peaty mud, the basin stratigraphy confirmed that the microdebitage found was dated back to the early Holocene age. There were 155 quartz microdebitage fragments identified. SEM images found key differences between quartz microdebitage and quartz that were not mechanically fractured. About 42% of the microdebitage particles were found to be “very angular to angular” (Sonnenburg, 2011).

This research proved to be a breakthrough for further studies in the Great Lakes because of its great potential due to new research methods. Although large stone tools often expose a variety of conjecture about the lives of hunter-gatherers, the study of microdebitage focuses on the concrete evidence; for example, the terrestrial archaeological sites are situated near quartzite cobbles. Thus, we can infer how hunter-gatherers chose specific locations to settle. Microdebitage offers archaeologists a solution to further study sites of interest that were previously unknown, undiscovered, and inaccessible. As opposed to looking all over the Great Lakes, microdebitage analysis narrows down potential locations of prehistoric findings, making research more efficient.

Ben Chiewphasa & Bailey Mueller

Sources:

Fladmark, K. 1982, Microdebitage analysis: Initial considerations: Journal of Archaeological Science, v. 9, p. 205-220.

Sonnenburg, E., J. Boyce, and E. Reinhardt. “Quartz Flakes in Lakes: Microdebitage Evidence for Submerged Great Lakes  Prehistoric (Late Paleoindian-Early Archaic) Tool-Making Sites.” Geology. Geological Society of America, 27 June 2011.
Web. 22 Sept. 2011. http://geology.gsapubs.org/content/39/7/631.full.

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