Humans have been altering our planet throughout the Holocene, but the scale of impacts increased dramatically in the mid-20th century, representing the start of the proposed Anthropocene Epoch. These pervasive anthropogenic impacts are comparable in magnitude, uniqueness, and geologic perseverance to the global changes that mark previous major geologic time intervals. To identify the geologic signals that characterize the Anthropocene, we have been studying sediment cores Jasper Ridge Biological Preserve in the eastern foothills of the San Francisco Peninsula, California. This has included analyses of mercury, lead, and other heavy metals; carbon and nitrogen isotopes; radionuclides from nuclear fallout; and microfossils (pollen and microcrustaceans) which record local indications of human impacts.
Jasper Ridge recent update:
2023 Publication in the Anthropocene Review:
HKW Anthropocene Curriculum: