biostudies-literatureUnknown12(2)McCarthy FMNatural Sciences and Engineering Research Council of CanadaBrock UniversityHaus der Kulturen der WeltKulturveranstaltungen des Bundes in BerlinFour years after the Anthropocene Working Group (AWG) voted to work toward defining the Anthropocene series/epoch with a base in the mid-20th C, the varved sediments of Crawford Lake (Milton, ON, Canada) were selected as the Global boundary Stratotype Section and Point (GSSP) candidate. The initial major rise in activity of ^{239 + 240}Pu had been selected as the primary chronostratigraphic marker to define the base of the Anthropocene, but the precise year when this occurred could not be determined from measurements of samples combining multiple varves. Individual varves from freeze cores collected in April 2023 provide annual resolution for bomb radionuclides, allowing the varve age model to be refined, former assignments determined to have been 1 year too old. The increase in <sThe anthropocene review243-272https://www.ebi.ac.uk/biostudies/studies/S-EPMC12317751biostudies-literatureHigh-resolution analysis of the varved succession at Crawford lake across the base of the proposed Crawfordian stage and Anthropocene series.PMC12317751Head MJCumming BFRose NLCundy ABGaca PSteier PLafond KMHain KBoyce JIPatterson RTHamilton PBWalsh CPisaric MFMcCarthy FMTurner SDBoom AfalseHigh-resolution analysis of the varved succession at Crawford lake across the base of the proposed Crawfordian stage and Anthropocene series.Four years after the Anthropocene Working Group (AWG) voted to work toward defining the Anthropocene series/epoch with a base in the mid-20th C, the varved sediments of Crawford Lake (Milton, ON, Canada) were selected as the Global boundary Stratotype Section and Point (GSSP) candidate. The initial major rise in activity of ^{239 + 240}Pu had been selected as the primary chronostratigraphic marker to define the base of the Anthropocene, but the precise year when this occurred could not be determined from measurements of samples combining multiple varves. Individual varves from freeze cores collected in April 2023 provide annual resolution for bomb radionuclides, allowing the varve age model to be refined, former assignments determined to have been 1 year too old. The increase in <s2025-01-01T00:00:00Z2025 Aug2026-03-15T22:18:53.679Z2025-08-13T03:06:27.802ZS-EPMC123177514075638310.1177/20530196251315454