02033nas a2200313   4500000000100000008004100001100001900042700001800061700002000079700001700099700001600116700002000132700001600152700001600168700001900184700001600203700001400219700001600233700002200249700001800271700001400289700001500303700001700318245008600335856004600421300001100467490000700478520123400485       2023                            d1 aStephen Himson1 aMark Williams1 aJan Zalasiewicz1 aColin Waters1 aMary McGann1 aRichard England1 aBruce Jaffe1 aArnoud Boom1 aRachael Holmes1 aSue Sampson1 aCerin Pye1 aJuan Berrio1 aGenevieve Tyrrell1 aIan Wilkinson1 aNeil Rose1 aPawel Gaca1 aAndrew Cundy00aThe San Francisco Estuary, USA as a reference section for the Anthropocene series  uhttps://doi.org/10.1177/20530196221147607  a87-1150 v103 aA San Francisco Estuary core was analysed at high resolution to assess its component stratigraphic signatures of the Anthropocene in the form of non-native species, Hg, spheroidal carbonaceous particles, δ13Corg, δ15N, radiogenic materials, and heavy metals. Time series analysis of the core using Ti data provides a chronology to depth 167 cm into the 1960s. Below this, to depth 230 cm, the lowermost part of the core may extend to the 1950s or potentially a little earlier. The earliest anthropogenic marker recorded in the core is the excursion in Hg (beginning at 190 cm) which may denote the early 1960s and is the closest stratigraphic marker in the core to the proposed mid-20th century timing for the onset of the Anthropocene. Biostratigraphical signatures of non-native species arriving in the 1970s\textendash1980s are widespread key markers and are significant tools for the correlation of Anthropocene deposits across the estuary. The absence of signals that indicate pre-1950s deposits precludes the use of the core to mark the Holocene\textendashAnthropocene boundary. However, the core provides an important reference section to demonstrate the palaeontological distinctiveness of Anthropocene series deposits.