Hydrogen isotope biogeochemistry reactors in 1988, but nuclear weapons testing in the 1950s added large spikes of radioactive elements to the atmosphere, especially radiocarbon and tritium. This complicated measurements for geologists using radiometric dating of carbon. However, some oceanographers benefited from the tritium increase, utilizing the signal in the water to trace physical mixing of water masses. In biogeochemistry, scientists focused primarily on the stable isotope of deuterium as a tracer for environmental processes, especially the water cycle. The American geochemist Harmon Craig, once a graduate student of Urey's, discovered the relationship between rainwater's hydrogen and oxygen isotope ratios. The linear correlation between
Ixcateopan (archaeological site) de productos derivados del algodón, materia prima que debió ser la principal fuente de abasto y de culto en la región. The archaeological zone consists of a series of overlays built on a natural elevation of the terrain, which occupies approximately 5 thousand square meters. Construction materials employed include: stone slabs, marble, limestone, boulders; and stucco and red paint used for finishing. Ceramic artifacts are a large and important group of samples found, generally mentioned in archaeological reports, serve to describe as well as chronological placement of sites, although seldom are investigation and study specific subjects The typical ceramics used