Pecos River

The town of Artesia is located in the southeast comer of New Mexico (Fig. 1). The Artesia Yard, which is used for a variety of road repair and maintenance activities, is located along the west side of town on flat terrain that slopes from west to east toward the Pecos River. 

We have also subjected two modem samples to severe plasma treatments, far more vigorous than needed for dating and stable carbon isotopic analyses. These were (i) a piece of a T-shirt label, chosen because it had small writing that would make visual changes easy to see and (ii) a peyote button, selected because we had been asked to date an archaeological peyote button thought to be -7-8,000 BP excavated from Shumla Cave in the Lower Pecos River region of Texas. The results of the 5 C measurements on CO2 produced from our plasma chemical extractions on five different samples are shown in Table II. 

Average value of oxalate crusts from the Lower Pecos River region of southwest Texas. 

Prehistoric rock art (Fig. 2) from the Pecos River Culture, Seminole Valley, and Big Bend, Texas, U.S.A. an important grouping of 270 sites dating from about 4000 BC [7-9]. 

Figure 2 Rock art from Seminole Valley, Texas, Pecos River culture from -4000 bc the effect of the environmental deterioration can be seen in the spallation of fragments from the substrate. 

On the North American continent (Boatwright, 1990), a race of people living west of the Pecos River in Texas about 9000 b.c. also learned how to make a primitive paint. These people used their primitive paints in much the same manner as their European and Australian counterparts to paint the rock walls of their living quarters wdth pictures of animals and people. Their paints were also made of natural pigments and whatever binders they could procure. 

Weathering of continental rocks increases their TDS and concentrations of calcium and bicarbonate relative to sodium and chloride. The composition of streams so affected plot to the left of both diagrams and include the Columbia, Mississippi, Yukon, and Thames rivers. Evaportranspiration from arid climate drainage basins and streams such as the Colorado, Pecos, and Jordan rivers, which receive soil runoff and irrigation return waters, further increase the Na and TDS content of streams. Concomitant precipitation of CaC03 further shifts the prevalent chemical character of such streams back toward NaCl and the chemistry of seawater. 

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