A 6,000 year record of environmental change from the eastern Pacific margin of central Mexico

QUATERNARY SCIENCE REVIEWS

卷:202

Article

Davies, Sarah J.¹  Metcalfe, Sarah E.²  Aston, Benjamin J.^1,9  Byrne, A. Roger³  Champagne, Marie R.⁴  Jones, Matthew D.²  Leng, Melanie J.^5,6  Noren, Anders^7,8 

[1] Aberystwyth Univ, Dept Geog & Earth Sci, Aberystwyth SY23 3DB, Dyfed, Wales

[2] Univ Nottingham, Sch Geog, Univ Pk, Nottingham NG7 2RD, England

[3] Univ Calif Berkeley, Dept Geog, 505 McCone Hall 4740, Berkeley, CA 94720 USA

[4] US Geol Survey, Quaternary Paleoenvironm Res Lab, Geol Minerals Energy & Geophys, 345 Middlefield Rd,MS 975, Menlo Pk, CA 94025 USA

[5] British Geol Survey, NERC Isotope Geosci Facilt, Nottingham NG12 5GG, England

[6] Univ Nottingham, Sch Biosci, Ctr Environm Geochem, Sutton Bonington Campus, Loughborough LE12 5RD, Leics, England

[7] Univ Minnesota, Dept Earth Sci, Continental Sci Drilling Coordinat Off, 500 Pillsbury Dr SE, Minneapolis, MN 55455 USA

[8] Univ Minnesota, Dept Earth Sci, LacCore Facil, 500 Pillsbury Dr SE, Minneapolis, MN 55455 USA

[9] Environm Assessment Team, Yorkshire Water, Western House,Western Way, Bradford BD6 2SZ, W Yorkshire, England

关键词: Holocene;    Palaeolimnology;    North America;    Diatoms;    Geochemistry;    Pollen;   

DOI  :  10.1016/j.quascirev.2018.11.008

来源: Elsevier

【 摘 要 】

The transition from the mid-to late-Holocene in MesoAmerica saw increasing complexity in spatial patterns of change. Records from the western part of the region are sparse, with lacustrine sequences affected by long term anthropogenic disturbance or lacking chronological resolution. Here, we present a continuous palaeoecological and geochemical record from Laguna de Juanacatlan, a remote lake in the mountains of the western TMVB. Diatom assemblages, XRF scanning data and bulk organic geochemistry from a well-dated, 7.25-m laminated sequence were combined with summary pollen data from a 9-m partially laminated core to provide a continuous record of catchment and lake ecosystem changes over the last c. 6000 years. Relatively humid conditions prevailed prior to c. 5.1 cal ka, which supported dense oak-pine forest cover around a deep, stratified lake. A trend towards drier conditions began c. 5.1 cal ka, intensifying after 4.0 cal ka, consistent with weakening of the North American Monsoon. Between 3.0 and 1.2 cal ka, lower lake levels and variable catchment run-off are consistent with increasing ENSO influence observed in the Late Holocene in the neotropics. From 1.2 to 0.9 cal ka, a marked change to catchment stability and more intense stratification reflected drier conditions and/or reduced rainfall variability and possibly warmer temperatures. After 0.9 cal ka, conditions were wetter, with an increase in catchment disturbance associated with the combined effects of climate and human activity. In recent decades, the lake ecosystem has changed markedly, possibly in response to recent climate change as well as local catchment dynamics. (C) 2018 Elsevier Ltd. All rights reserved.

【 授权许可】

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