DOI: 10.1016/j.palaeo.2013.12.004
论文题名: Palynofacies and stable C and N isotopes of Holocene sediments from Lake Macuco (Linhares, Espírito Santo, southeastern Brazil): Depositional settings and palaeoenvironmental evolution
作者: Lorente F.L. ; Pessenda L.C.R. ; Oboh-Ikuenobe F. ; Buso Jr. A.A. ; Cohen M.C.L. ; Meyer K.E.B. ; Giannini P.C.F. ; de Oliveira P.E. ; Rossetti D.F. ; Borotti Filho M.A. ; França M.C. ; de Castro D.F. ; Bendassolli J.A. ; Macario K.
刊名: Palaeogeography, Palaeoclimatology, Palaeoecology
ISSN: 0031-0182
出版年: 2014
卷: 415 起始页码: 69
结束页码: 82
语种: 英语
英文关键词: Carbon and nitrogen isotopes
; Holocene
; Organic matter
; Palynofacies
; Southeastern Brazil
英文摘要: Particulate organic matter in sediments constitutes a valuable proxy for paleoenvironmental reconstructions. A 192cm lacustrine sediment core (~7521calyr. B.P.) from the northern coast of the State of Espírito Santo, southeastern Brazil, was radiocarbon dated and then analyzed for palynofacies, stable isotopes (C and N), and grain size. The values for total organic carbon - TOC (1.91% to 20.89%), total nitrogen - TN (0.08% to 1.1%), δ13C (-27.10% to -29.01%), δ15N (1.92% to 5.09%) and C/N (12.87 to 50.11) suggest predominance of C3 plants and changing mixtures of terrestrial and aquatic organic matter in the sediments. Palynofacies and cluster analyses were used to identify four palynofacies associations that reflect different phases in the Lake Macuco evolution. Palynofacies 1 (192 to 106cm, ~7521calyr. B.P. to ~7054calyr. B.P.-interpolated age) is characterized mainly by amorphous organic matter (AOM), non-opaque phytoclasts (NOPs), mangrove pollen grains (Rhizophora sp. L. 1753 and Avicennia sp. L. 1753), and foraminiferal test linings. Palynofacies 2 (106 to 65cm, ~7054calyr. B.P.-interpolated age to ~4847calyr. B.P.) is dominated by NOPs and AOM, with an increase in the values of mangrove pollen grains relative to Palynofacies 1. Both palynofacies reflect marine and fluvial influences in a depositional environment related to the development of an estuarine system during the mid-Holocene transgressive stage. Palynofacies 3 (65 to 27cm, ~4847calyr. B.P. to ~3800calyr. B.P.-interpolated age) comprises high abundances of fluvial elements (NOP and opaque phytoclasts-OP) and low values of AOM. The depositional environment is interpreted as being an estuary during the marine regression, with the displacement of the estuarine basin and mangroves towards the sea. Palynofacies 4 (27 to 0cm, <~3800calyr. B.P.) is characterized by the predominance of AOM and NOP, increase in the values of freshwater algae, and no evidence of marine influence. This last phase reflects the beginning of the establishment of Lake Macuco and floodplain of the Barra Seca River under conditions similar to the present-day. © 2013 Elsevier B.V. All rights reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/69179
Appears in Collections: 过去全球变化的重建
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作者单位: Center for Nuclear Energy in Agriculture (CENA), Piracicaba, SP, Brazil; Missouri University of Science and Technology, Rolla, MO, United States; Federal University of Pará, PA, Brazil; Federal University of Minas Gerais, MG, Brazil; University of São Paulo, SP, Brazil; São Francisco University, SP, Brazil; National Institute of Space Research, SP, Brazil; Fluminense Federal University, RJ, Brazil
Recommended Citation:
Lorente F.L.,Pessenda L.C.R.,Oboh-Ikuenobe F.,et al. Palynofacies and stable C and N isotopes of Holocene sediments from Lake Macuco (Linhares, Espírito Santo, southeastern Brazil): Depositional settings and palaeoenvironmental evolution[J]. Palaeogeography, Palaeoclimatology, Palaeoecology,2014-01-01,415