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1. Insights into Intragroup Variation in Precontact Paleodiet: A Middle Period Example from San Mateo County

   Goring, Daniel ; Eerkens, Jelmer W. ; Canzonieri, Chris ; Zwierlein, Irenne ; Zimmer, Michelle ; Bartelink, Eric J. ( November 2020 , Proceedings of the Society for California Archaeology)

   null (Ed.)

   This article reports new carbon, nitrogen, and sulfur isotope data for 10 individuals on the San Francisco Peninsula from CA-SMA-78 (Hamilton Mound 20; n = 6), CA-SMA-160 (Hiller Mound; n = 3), and a previously unrecorded site in downtown San Mateo (n = 1). We also report seven new bone collagen accelerator mass spectrometry radiocarbon dates, three from CA-SMA-78 that fall during the Early-Middle Transition and early Middle Period (ca. 2,400 and 1,700 cal BP), three from CA-SMA-160 that fall during the late Middle and Middle-Late Transition periods (ca. 1,080 and 770 cal BP), and one from the unrecorded site that falls during the Late Middle Period (ca. 1,260 cal BP). Dietary isotopes show a bimodal pattern, with most individuals (n = 8) consuming a mixed marine-terrestrial diet and two a terrestrial-dominant diet (n = 2). We propose two hypotheses to explain this variation, the first suggesting independent family-level hunting and gathering territories combined with little intra-group sharing of food, and the second suggesting exogamous marriage patterns with people migrating from regions to the south. Future isotopic research could provide support for one (or both) of these hypotheses. 

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2. Sex‐biased parental investment and female wealth accumulation in ancient California

   https://doi.org/10.1002/ajpa.24806  

   Greenwald, Alexandra M. ; Burns, Gregory R. ; Eerkens, Jelmer W. ; Bartelink, Eric J. ; Leventhal, Alan ; Arellano, Monica V. ( July 2023 , American Journal of Biological Anthropology)

   The mortuary record at Middle Period siteKalawwasa Rummeytak(CA‐SCL‐134) (2600‐1225 cal BP) in California's southern Santa Clara Valley shows pronounced wealth inequality;Olivellashell bead wealth, as well as other grave goods, are concentrated in the burials of several older adult females. The concentration of wealth among women, along with regional strontium isotopic evidence of male‐biased residential shifts in early adulthood, suggests a matrilineal kinship system that practiced matrilocal post‐marital residence patterns. We suggest local resource enhancement effects incentivized keeping women in their natal communities and investing more in female offspring.

   With the consent of, and in collaboration with, the Muwekma Ohlone Tribe of the San Francisco Bay Area, this paper employs isotopic analysis (δ¹⁵N andδ¹³C,⁸⁶Sr/⁸⁷Sr) to examine duration of exclusive breastfeeding, weaning age (complete cessation of breastmilk consumption), early childhood diet, and lifetime residential mobility of individuals interred atKalawwasa Rummeytakto test the assumption that the site inhabitants favored matrilocality and that female offspring received greater levels of investment in groups with female wealth/status attainment. First molars, third molars, and bone was sampled from 22 individuals.

   The average weaning age for females atKalawwasa Rummeytakis 36.3 months ± 9.7 (1 SD), or just over 3 years. The average weaning age for males is 31.2 ± 7.9 months (1 SD), or about 2.6 years. Infants at the site were provisioned with supplemental foods dominated by C₃plants and terrestrial herbivores, as well as anadromous fish. After weaning, individuals consumed a diet dominated by acorns, C₃plants, and terrestrial herbivores, with periodic inclusion of anadromous fish. 30% of the sampled population of females exhibit local first molar⁸⁷Sr/⁸⁶Sr values, suggesting thatKalawwasa Rummeytakis their natal community. None of the males interred at the site are locals.

   Despite the small sample size often unavoidable in archaeological contexts, we find possible female‐biased parental investment strategies. Cessation of breastfeeding (weaning) was, on average, 5 months earlier for males compared to females. There are no differences between females and males in the consumption of supplemental or post‐weaning foods. Strontium data suggest a flexible postmarital residence system that favored matrilocality. This may have incentivized greater investment in female offspring.

    

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3. A late Wisconsin (32–10k cal a BP) history of pluvials, droughts and vegetation in the Pacific south‐west United States (Lake Elsinore, CA)

   https://doi.org/10.1002/jqs.3018  

   Kirby, M. E. ; Heusser, L. ; Scholz, C. ; Ramezan, R. ; Anderson, M. A. ; Markle, B. ; Rhodes, E. ; Glover, K. C. ; Fantozzi, J. ; Hiner, C. ; et al ( February 2018 , Journal of Quaternary Science)

   Continuous, sub‐centennially resolved, paleo terrestrial records are rare from arid environments such as the Pacific south‐west United States. Here, we present a multi‐decadal to centennial resolution sediment core (Lake Elsinore, CA) to reconstruct late Wisconsin pluvials, droughts and vegetation. In general, the late Wisconsin is characterized by a wetter and colder climate than during the Holocene. Specifically, conditions between 32.3 and 24.9k cal a BP are characterized by large‐amplitude hydrologic and ecologic variability. Highlighting this period is a ∼2000‐year glacial mega‐drought (27.6–25.7k cal a BP) during which the lake shallowed (3.2–4.5 m depth). This period is approximately coeval with a Lake Manix regression and an increase in xeric vegetation in the San Bernardino Mountains (Baldwin Lake). The Local Last Glacial Maximum (LLGM) is bracketed between 23.3 and 19.7k cal a BP − a ∼3000‐year interval characterized by reduced run‐off (relative to the glacial), colder conditions and vegetative stability. Maximum sustained wetness follows the LLGM, beginning at 19.7 and peaking by 14.4k cal a BP. A two‐step decrease in runoff characterizes the Lateglacial to Holocene transition; however, the vegetation change is more complex, particularly at the beginning of the Younger Dryas chronozone. By 12.6–12.4k cal a BP, the climate achieved near Holocene conditions.

    

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4. Stable Isotopic Analysis at the Ancestral Ohlone Site of Yakmuy ‘Ooyákma-Tka (“Place of the East Ridge Site”): A Comparative Study of Prehistoric Dietary Variation

   Alexandria M. Firenzi, Alina Tichinin ( January 2022 , Proceedings of the Society for California Archaeology)

   We examine how Late Holocene people living at the ancestral Ohlone site of Yakmuy ‘Ooyákma-tka (“Place of the East Ridge Site” [CA-SCL-215]) interacted with their environment based on the foods they consumed. We examine dietary variation among 32 individuals buried at the site, located within the current city of San Jose. Radiocarbon dates indicate that Yakmuy ‘Ooyákma-tka spans the M4 phase of the Middle Period through the first half of the Middle to Late Period Transition (870 and 1170 ACE). This study examines carbon and nitrogen isotopes to provide insight into dietary variation, focusing especially on differences by sex and age. We show that Yakmuy ‘Ooyákma-tka inhabitants consumed mainly low trophic level resources, consistent with an almost entirely vegetarian based diet. Dietary variation among males and females follows a distinct life history pattern wherein dietary proteins increased markedly in females during their reproductive years and declined in their older years. 

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5. Holocene hydroclimate in highland Costa Rica: new evidence from hydrogen and carbon isotopes in n ‐alkanes of terrestrial leaf waxes in a 10 000‐year sediment profile

   https://doi.org/10.1002/jqs.3616  

   Kerr, Matthew T. ; Horn, Sally P. ; Lane, Chad S. ( March 2024 , Journal of Quaternary Science)

   We conducted compound‐specific stable hydrogen (δD) and carbon (δ¹³C) isotope analysis onn‐alkanes from terrestrial leaf waxes preserved in a 10 000‐year sediment profile from Lago de las Morrenas 1 (9.4925° N, 83.4848° W, 3480 m), a glacial lake on the Chirripó massif of the Cordillera de Talamanca in Costa Rica. Our results demonstrate millennial‐scale variations in hydroclimate across the Holocene, with drier than average conditions in the highlands during the early Holocene, but with gradually increasing precipitation; mesic conditions during the middle Holocene with a gradual drying trend; and highly variable conditions during the late Holocene. This general pattern is punctuated by several centennial‐scale manifestations of global climate events, including dry conditions during the 8200, 5200 and 4200 cal a bpevents and the Terminal Classic Drought (1200–850 cal a bp). Our δ¹³C analyses demonstrate that carbon isotope signals are responding to changes in hydroclimate at the site and reinforce prior interpretations of a stable páramo plant community that established following deglaciation and persisted throughout the Holocene. The shifts in hydroclimate inferred from analyses ofn‐alkanes in Lago de las Morrenas 1 sediments show correspondence with charcoal records in multiple lakes, with fires most common during drier intervals.

    

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