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Abstract Significant sediment flux and deposition in a sedimentary system are influenced by climate changes, tectonics, lithology, and the sedimentary system's internal dynamics. Identifying the timing of depositional periods from stratigraphic records is a first step to critically evaluate the controls of sediment flux and deposition. Here, we show that ages of single‐grain K‐feldspar luminescence subpopulations may provide information on the timing of previous major depositional periods. We analyzed 754 K‐feldspar single‐grains from 17 samples from the surface to ∼9 m‐depth in a trench located downstream of the Mission Creek catchment. Single‐grain luminescence subpopulation ages significantly overlap at least eight times since ∼12.0 ka indicating a common depositional history. These depositional periods correspond reasonably well with the Holocene intervals of wetter than average climate conditions based on hydroclimatic proxies from nearby locations. Our findings imply a first‐order climatic control on sediment depositional history in southern California on a millennial timescale.
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Bayesian ages for pollen records since the last glaciation in North America
Abstract Terrestrial pollen records are abundant and widely distributed, making them an excellent proxy for past vegetation dynamics. Age-depth models relate pollen samples from sediment cores to a depositional age based on the relationship between sample depth and available chronological controls. Large-scale synthesis of pollen data benefit from consistent treatment of age uncertainties. Generating new age models helps to reduce potential artifacts from legacy age models that used outdated techniques. Traditional age-depth models, often applied for comparative purposes, infer ages by fitting a curve between dated samples. Bacon, based on Bayesian theory, simulates the sediment deposition process, accounting for both variable deposition rates and temporal/spatial autocorrelation of deposition from one sample to another within the core. Bacon provides robust uncertainty estimation across cores with different depositional processes. We use Bacon to estimate pollen sample ages from 554 North American sediment cores. This dataset standardizes age-depth estimations, supporting future large spatial-temporal studies and removes a challenging, computationally-intensive step for scientists interested in questions that integrate across multiple cores.
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- Award ID(s):
- 1655898
- PAR ID:
- 10153743
- Publisher / Repository:
- Nature Publishing Group
- Date Published:
- Journal Name:
- Scientific Data
- Volume:
- 6
- Issue:
- 1
- ISSN:
- 2052-4463
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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