The western shoal of the Lingding Bay is known to be an important deposition zone of terrestrial substance in the Pearl River Estuary (PRE). In this study, the vertical variations of concentration and fluxes of polycyclic aromatic hydrocarbon (PAH) are investigated in a core from the west shoal of Lingding Bay. In combining with 210Pb-dating, the PAHs sedimentary record in the last 100 years is reconstructed. The sigmaPAH concentration ranged from 59 ng x g(-1) to 330 ng x g(-1) throughout the core with two distinct peaks. An initial increase in sigmaPAH concentration was found around the 1860s, followed with the first maximum in the 1950s. There was a decrease in total PAHs concentration and flux in 1960s and 1970s. A sharp increase in PAHs levels was observed from 1980s and a maximum was found in the 1990s. PAHs diagnostic ratios indicate that PAH in the sediment core are mainly of pyrolytic origin. PAHs concentrations are found to correlate positively with the Gross Domestic Production, vehicle numbers and power generation in the surrounding regions, indicating that the PAHs in the sediment core are mainly anthropogenic. Atmospheric deposition and land runoff may serve as the important pathway of PAHs input to the sediment.
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Sci Rep
January 2025
Westchase Software, Houston, TX, 77063, USA.
It is well known that the sedimentary rock record is both incomplete and biased by spatially highly variable rates of sedimentation. Without absolute age constraints of sufficient resolution, the temporal correlation of spatially disjunct records is therefore problematic and uncertain, but these effects have rarely been analysed quantitatively using signal processing methods. Here we use a computational process model to illustrate and analyse how spatial and temporal geochemical records can be biased by the inherent, heterogenous processes of marine sedimentation and preservation.
View Article and Find Full Text PDFNat Commun
January 2025
Department of Evolutionary Anthropology, University of Vienna, Vienna, Austria.
Caves are primary sites for studying human and animal subsistence patterns and genetic ancestry throughout the Palaeolithic. Iberia served as a critical human and animal refugium in Europe during the Last Glacial Maximum (LGM), 26.5 to 19 thousand years before the present (cal kya).
View Article and Find Full Text PDFAn Acad Bras Cienc
December 2024
Universidade Federal do Rio de Janeiro, Departamento de Geologia e Paleontologia, Laboratório de Sistemática e Tafonomia de Vertebrados Fósseis (LAPUG), Museu Nacional, Campus de Pesquisa e Ensino, Avenida Bartolomeu de Gusmão, 875, São Cristóvão, 20941-160 Rio de Janeiro, RJ, Brazil.
Shell beds, or coquinas, have a complex origin, limiting their utility in paleoecology. However, such accumulations can serve as crucial paleoenvironmental indicators, since their bioestratinomic and diagenetic properties explain the physical-chemical and biological processes of their formation, as well as the ancient environments linked to their development. In 2016, the PALEOANTAR Project sampled coquinas from the James Ross Island (Antarctic Peninsula) in Passo São José (PSJ - San José Way) and Muro do Castelo (MDC - Castle Wall), two new localities with outcrops of the lower Lachman Crags Member, Santa Marta Formation, Marambio Group, Cretaceous of Larsen Basin.
View Article and Find Full Text PDFThe diversity and abundance of diagenetic textures observed in sedimentary rocks of the clay-sulfate transition recorded in the stratigraphic record of Gale crater are distinctive within the rover's traverse. This study catalogs all textures observed by the MAHLI instrument, including their abundances, morphologies, and cross-cutting relationships in order to suggest a paragenetic sequence in which multiple episodes of diagenetic fluid flow were required to form co-occurring color variations, pits, and nodules; secondary nodule populations; and two generations of Ca sulfate fracture-filling vein precipitation. Spatial heterogeneities in the abundance and diversity of these textures throughout the studied stratigraphic section loosely correlate with stratigraphic unit, suggesting that grain size and compaction controls on fluid pathways influenced their formation; these patterns are especially prevalent in the Pontours member, where primary stratigraphy is entirely overprinted by a nodular fabric, and the base of the stratigraphic section, where increased textural diversity may be influenced by the underlying less permeable clay-bearing rocks of the Glen Torridon region.
View Article and Find Full Text PDFMar Environ Res
November 2024
Estación el Carmen, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Carretera Carmen-Puerto Real km 9.5, 24157, Ciudad del Carmen, Campeche, Mexico. Electronic address:
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