The response of sediments on recent environmental changes was studied using Pb-210 technique of dating of sediments followed by the INAA determination of major and trace element composition of four sediment cores collected in the Gulf of California along the eastern coast of the Peninsula of Baja California.
Vertical profiles of Ca and Sc reveal regionally important weak tendency to the growth of Ca content in upper layers of all sediment cores during last decades, probably caused by the increase of the deposition of calcium carbonates, which could be induced in its turn by the anthropogenically controlled elevation of the carbon dioxide concentration in the atmosphere and related increase of the primary productivity of waters of the Gulf of California.
Historical records also manifest two kind of local anthropogenic influences : a) the increase of Zn , Zr and As contents in Santa Rosalia sediment core in layers which correspond in time scale to the period of copper mining and smelting of the ores ; b) the changes of Ca/Sc ratio (biogenic/terrigenic contribution) to the sediments of the El Coyote sediment core collected in the deep Alfonso Basin of the La Paz Bay which correlates with the time of the accelerated agricultural and economic development of the adjacent drainage basin in 1960s-1980s.