10 that may be the result of human disturbance this inference is supported by independent evidence from geographic, palynologic, and dendroclimatologic data. The ostracode record shows some evidence of a progressive salinization process between A. Trace element data were used to reconstruct the canal water chemistry and to propose paleoclimatic and human-impact hypotheses for environmental change. Reconstructing Ancient Hohokam Irrigation Systems in the Middle Gila River Valley, Arizona, United States of America Zhu Tianduowa1 & Kyle C. Valves of Limnocythere staplini, Candona patzcuaro, and Cypridopsis vidua were analyzed using inductively coupled plasma mass spectrometry (ICP-MS) to determine the Mg/Ca and Sr/Ca ratios. Thus, fossil ostracodes reflect the water chemistry in which the valves were precipitated. Magnesium and strontium are commonly incorporated into the shell as trace elements, which can be used to track paleotemperature and paleosalinity variations.

Low-Mg calcite ostracode carapaces form in thermal and chemical equilibrium with the host water. Their fossil record in Hohokam canals can provide useful data to understand human/environment relationships in the past. Ostracodes are sensitive to hydrochemical changes. Hohokam irrigation systems were fragile and subject to episodic damage and destruction. Irrigation canals from rivers to the fields downstream were the answer. In the warmth of their arid environment the Hohokam could produce two crops a yearas long as they had enough water. They planned to take water from the Salt River by. The Hohokam were an agricultural people who supplemented their primary crop of maize with hunting, fishing, and gathering fruits and nuts. Environmental archaeology studies on samples from an agricultural context provide information that may be used to answer questions of climatic vs. In December 1867, a group of 17 of these new arrivals formed the Swilling Irrigation and Canal Company.