The nonmarine environment of Quaternary foraminifers in Yanghuzhuang, China: Evidence from boron and strontium isotopes

The concentrations and isotopic compositions of boron and strontium of Quaternary foraminifers and bivalve fossils collected in the Yanghuzhuang section of Yanqing, Beijing and of modern gastropods living in the Guishui River and of river water were measured. The concentrations and isotopic compo- sitions of Quaternary foraminifers and bivalve fossils differed from those of modern marine fo- raminifers and were similar to those of modern terrestrial gastropods from the Guishui River. These results indicate that early Quaternary foraminifers in the Yanghuzhuang section inhabited a nonmarine environment and that these foraminifers were not the result of a transgression or sea flooding. The foraminifers were not special halobios and can survive in the terrestrial condition that resembled those of the ocean.