Stone Cooking Tool Residue Shed Lights On Ancient Food

New investigation digs into really ancient chromatic kitchens sphere nutrient secrets.

The mortar, pestle and cutting committee successful your room are modern versions of manos and metates—ancient cooking implements recovered successful archaeological sites astir nan world.

A mano is simply a hand-held chromatic instrumentality utilized pinch a metate to grind and pulverize nutrient materials from plants and animals. The metate is simply a large, level portion of chromatic aliases a slump crushed into a bedrock surface. These bedrock metates, besides known arsenic open-air metates, are peculiarly communal astatine archaeological sites, pinch nan oldest making love arsenic acold backmost arsenic 15,500 years.

Now, researchers astatine nan Natural History Museum of Utah are utilizing caller techniques to extract microscopic works residues preserved wrong nan cracks and crevices of bedrock metates to study much astir nan group who put them there.

Their latest findings look successful nan diary American Antiquity.

“People person lived present for clip immemorial and person been processing autochthonal plants connected crushed chromatic devices for a agelong clip too,” says archaeobotanist Stefania Wilks, a Natural History Museum of Utah research adjunct and University of Utah postgraduate student, referring to nan Western US, wherever she conducts her research. That investigation includes studying plants that group utilized for nutrient and medicine to study astir accepted lifeways and really nan landscapes person changed complete time.

Currently, Wilks is moving pinch NHMU’s Curator of Archaeology Lisbeth Louderback, a University of Utah professor of anthropology, to retrieve works residues from metates crossed occidental North America. Not conscionable immoderate portion of works matter, though. Wilks and Louderback activity specifically pinch starch granules, mini structures wrong a works compartment utilized to shop power successful nan shape of carbohydrates. And those granules are itty-bitty: Even nan largest granules are smaller than a tenth of a millimeter.

The granules’ mini size intends scientists can’t spot them pinch their naked eye. They person to extract them from surfaces wherever group person processed plants, specified arsenic ground stone, pottery, and basketry. Louderback suspected that an untapped root of starch granules could beryllium bedrock metates. Although nan aboveground of nan stone is exposed to extracurricular elements that would expanse distant nan granules aliases degrade them complete time, she suspected that mini crevices successful nan stone could beryllium hiding works residue.

“Through their actions of grinding and mashing, group would person forced these starches down deeper into nan stone,” Wilks explains.

Bedrock metates tin beryllium evident aliases cryptic, and their quality depends connected nan type of stone and really it was ground. In Utah, for example, nan exposed bedrock is typically sandstone, and nan metates are often shaped arsenic an oblong groove. Other bedrock metates are circular, dish-shaped and immoderate are heavy and round, for illustration a modern-day mortar. Regardless of their shape, nan metates thin to look successful groups aliases lined up successful a row. “They aren’t sexy for illustration an arrowhead,” Wilks says, “…but they still incorporate valuable accusation astir what plants group processed successful nan past.”

Multiple bedrock metates hap on basalt outcrops successful nan uplands of confederate Oregon and are associated pinch thousands of petroglyph panels. Also occurring among these archaeological features are ample populations of culturally important plants, particularly geophytes (those pinch starchy underground retention organs for illustration roots and tubers). Archaeologists erstwhile assumed group only ventured up to nan uplands for hunting.

“We were up location testing to spot if nan bedrock metate surfaces were really being utilized to process plants,” Wilks says.

To do that, nan squad compared works residues connected nan aboveground of nan metates to those heavy wrong nan crevices. Using an electrical toothbrush and water, they scrubbed worldly from nan aboveground of nan metate. Then, they added a deflocculant—a constituent akin to laundry detergent—to break up clumped particles and merchandise them from heavy wrong nan stone. They applied nan electrical toothbrush again, and this time, nan worldly they collected was immoderate had been forced down into nan stone’s crevices. They repeated this process connected nan surfaces of adjacent rocks that weren’t utilized arsenic metates to service arsenic a control.

With samples successful hand, nan squad turned to their microscopes to observe starch granules. Both nan metate and power surfaces revealed virtually nary granules. But nan deeply-embedded samples contained hundreds.

“It accrued our assurance that what we were seeing was nonstop grounds that different works type pinch starchy organs were processed connected nan metate,” Wilks recalls.

Having proven that they could extract starch granules from nan bedrock metates, nan squad past began to found what works type nan granules came from. It was a time-consuming process: Wilks analyzed hundreds of starch granules from aggregate works type to study their morphological characteristics, past compared them to granules of works type presently increasing successful nan area.

They were capable to constrictive down nan works family of galore granules, and immoderate could moreover beryllium identified down to nan genus level. For example, members of nan carrot family were common, including a group of plants called biscuit root. They besides recovered chaotic grasses—most apt chaotic rye—and plants belonging to nan lily family. These are each works taxa that were, and proceed to be, important nutrient sources for section Indigenous groups.

“Starch study is adjuvant successful studying human diets of nan past because immoderate works parts don’t sphere successful nan archaeological record,” Wilks says.

Root vegetables, for example, will break down faster than seeds aliases grains. This caller method of recovering starch granules provides researchers different measurement to study nan domiciled of plants successful quality diets. It besides demonstrates really bedrock metates, often overlooked astatine archaeological sites, incorporate valuable accusation astir past quality lifeways.

Source: University of Utah