Time-averaging and stratigraphic resolution in death assemblages and Holocene deposits: Sydney Harbour’s molluscan record

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dc.contributor.authorDominguez, JGen_AU
dc.contributor.authorKosnik, MAen_AU
dc.contributor.authorAllen, APen_AU
dc.contributor.authorHua, Qen_AU
dc.contributor.authorJacob, DEen_AU
dc.contributor.authorKaufman, DSen_AU
dc.contributor.authorWhitacre, KEen_AU
dc.date.accessioned2017-05-03T05:08:59Zen_AU
dc.date.available2017-05-03T05:08:59Zen_AU
dc.date.issued2016-11-01en_AU
dc.date.statistics2017-04-03en_AU
dc.description.abstractTime-averaging has evolved from an unrecognized variable in paleoecological analyses to a key concept in understanding the dynamics of sedimentary systems and the formation of fossil deposits. Here we used radiocarbon-calibrated amino acid racemization ages from 173 Fulvia tenuicostata shells collected from Sydney Harbour (NSW, Australia) to quantify time-averaging in surficial and excavated death assemblages. A novel approach to estimating the total age-estimate variability of a collection of specimens is presented that integrates the age-estimation error associated with the AAR calibration model and the effect of time-averaging variability on the age distribution. Fulvia collected from a single 1.6-m deep excavation were used to quantify changes in time-averaging with burial depth. Fulvia collected from surficial death assemblages at six sites were used to quantify spatial variation in time-averaging. The median shell age increased from ∼ 150 yr to ∼ 4230 yr and time-averaging from ∼ 40 yr to ∼ 960 yr with increased burial depth. While four sites contained surface shell assemblages with median ages of ∼ 150 yr and time-averaging of ∼ 40 yr, two sites had death assemblages with older median ages and time-averaging > 1900 yr. A decline in the abundance of Fulvia in the post-colonial period is likely responsible for the rarity of very young shells in the surface death assemblages, while local factors such as dredging and other human activities are likely responsible for the total age-estimate variability in the two highly time-averaged surface collections. These analyses provide a geochronological context for assessing ecological changes in the harbor's benthic communities since colonization and offer an important perspective on the formation of Holocene fossil deposits. © 2016 GeoScience Worlden_AU
dc.identifier.citationDominguez, J. G., Kosnik, M. A., Allen, A. P., Hua, Q., Jacob, D. E., Kaufman, D. S., & Whitacre, K. (2016). Time-averaging and stratigraphic resolution in death assemblages and Holecene deposits: Sydney Harbour's molluscan record. Palaios, 31(11), 564-575. doi:10.2110/palo.2015.087en_AU
dc.identifier.govdoc7715en_AU
dc.identifier.issn1938-5323en_AU
dc.identifier.issue11en_AU
dc.identifier.journaltitlePalaiosen_AU
dc.identifier.pagination564-575en_AU
dc.identifier.urihttps://doi.org/10.2110/palo.2015.087en_AU
dc.identifier.urihttp://apo.ansto.gov.au/dspace/handle/10238/8663en_AU
dc.identifier.volume31en_AU
dc.language.isoenen_AU
dc.publisherGeoScience Worlden_AU
dc.subjectSample holdersen_AU
dc.subjectQuaternary perioden_AU
dc.subjectMolluscsen_AU
dc.subjectAmino acidsen_AU
dc.subjectAge estimationen_AU
dc.subjectFossilsen_AU
dc.titleTime-averaging and stratigraphic resolution in death assemblages and Holocene deposits: Sydney Harbour’s molluscan recorden_AU
dc.typeJournal Articleen_AU
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