Mollusks consumption during the prehistory of Baja California
SPECIAL ARTICLE
Permanent or seasonal collection ?
Mollusks consumption during the prehistory of Baja California
By Enah Fonseca Ibarra
The rests of marine resources can be found at hunting , collecting and fishing camps . How to determine when these resources were consumed ? One of the strategies to answer that question is using isotopic techniques .
Fig . 4 Ancient residents of Baja California fishing . Author : Luis Gabriel Razo .
T he study of oxygen isotope composition of mollusk shells is a tool used in archeology to estimate paleotemperature and to identify the season of capture , through an analysis of the terminal growth band of prehistoric mollusks . It is based on the idea that the oxygen isotope composition depends mainly on temperature and the isotope composition of seawater and not from other processes , such as nutrition or organismal metabolism ( Wefer y Berger , 1991 ). Concerning development of empiric relations between isotope composition of water ( δ18Ow ) and biogenic carbonates grown at different temperatures , Epstein et al ., ( 1953 ) proposed an equation to estimate the temperature .
The use of isotopic techniques , plus the analysis of ecological variables of archaeofauna materials found at archaeological sites has resulted into an efficient duality for paleoenvironment reconstruction , as well as the study of nutrition habits , capture strategies and settling patterns of the human groups that inhabited the coasts along the peninsula of Baja California ( Téllez et al ., 2008 ; Celis , 2011 , 2015 ; Robles , 2013 ). With the intention to continue this research , isotope values of Mytilus californianus were compared , these shells were collected in the archeological camps located in the area of Bajamar-Jatay in the northwestern coast of the Pacific Ocean ( Fig . 1 ).
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