Knowledge Resource Center for Ecological Environment in Arid Area
DOI | 10.1016/j.sedgeo.2015.04.012 |
Deciphering the history of hydrologic and climatic changes on carbonate lowstand surfaces: calcrete and organic-matter/evaporite facies association on a palimpsest Middle Jurassic landscape from Portugal | |
Azeredo, Ana C.1; Wright, V. Paul2; Mendonca-Filho, Joao3; Cristina Cabral, M.1; Duarte, Luis V.4 | |
通讯作者 | Azeredo, Ana C. |
来源期刊 | SEDIMENTARY GEOLOGY
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ISSN | 0037-0738 |
EISSN | 1879-0968 |
出版年 | 2015 |
卷号 | 323页码:66-91 |
英文摘要 | The unusual occurrence of calcretes and prominent organic matter in the Middle Jurassic (Lower Bathonian, Serra de Aire Formation) of the Lusitanian Basin of western Portugal (Western Iberian Margin) revealed a complex palimpsest exposure record, here interpreted as reflecting hydrological changes caused by phases of emergence and immersion. It serves as a potential model for understanding stratigraphic development at lowstand surfaces in carbonate successions. The exposure-dominated fades association grades upwards into peritidal and lagoonal limestones, and the interval is assigned to the regressive peak of a Transgressive-Regressive Facies Cycle (2nd order) of the thick Middle Jurassic carbonate ramp succession. The Galinha Quarry, Fatima region, NE of Lisbon, a type section for this lowstand assemblage, exhibits varied calcretes, with black-dasts, interbedded with, and grading into: organic-rich marly/clayey seams and lenses, locally with carbonate nodules; carbonates with evaporite traces; microbial laminites; black-clast and fenestral limestones; some lithofacies are dolomitized. The palynofacies contains phytoclasts associated with less refractory, more prone to degradation components, which suggests natural combustion/pyrolysis (wild fires). The lowstand surface represents a low relief landscape with small depressions/ponds bordering a more distal marginal-littoral setting; the partly subaerial and partly subaqueous settings were subjected to lengthy exposure and to fluctuating, very shallow water bodies and water table. Coeval climatic regime was a seasonally dry/wet one, with dry/semi-arid phases dominating over the sub-humid, as shown by the combined record of intense calcrete development, rhizogenic structures, microbial mats, brecciation, desiccation, evaporites and wild fire evidence. However, sea level rise caused changes to shallow, sea-water influenced restricted lagoonal-peritidal settings. Comparisons and differences with modern and ancient coast marginal carbonates are made to provide a guide to the variability in such lowstand deposystems in the stratigraphic record. (C) 2015 Elsevier B.V. All rights reserved. |
英文关键词 | Calcretes Organic matter Lowstand carbonates Middle Jurassic Portugal |
类型 | Article |
语种 | 英语 |
国家 | Portugal ; Wales ; Brazil |
收录类别 | SCI-E |
WOS记录号 | WOS:000356556000005 |
WOS关键词 | SUBBASIN LUSITANIAN BASIN ; DISCONTINUITY SURFACES ; PALUSTRINE CARBONATES ; BLACK PEBBLES ; FRENCH JURA ; PALYNOFACIES ; LACUSTRINE ; PALEOSOLS ; EXAMPLES ; PLATFORM |
WOS类目 | Geology |
WOS研究方向 | Geology |
资源类型 | 期刊论文 |
条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/190427 |
作者单位 | 1.Univ Lisbon, Fac Ciencias, Dept & Ctr Geol, IDL, P-1749016 Lisbon, Portugal; 2.Natl Museum Wales, Nat Sci, Cardiff CF1 3NP, S Glam, Wales; 3.Univ Fed Rio de Janeiro, Inst Geociencias, Dept Geol, Ilha Fundao, BR-21949900 Rio De Janeiro, Brazil; 4.Univ Coimbra, Fac Sci & Technol, MARE Marine & Environm Sci Ctr, P-3030790 Coimbra, Portugal |
推荐引用方式 GB/T 7714 | Azeredo, Ana C.,Wright, V. Paul,Mendonca-Filho, Joao,et al. Deciphering the history of hydrologic and climatic changes on carbonate lowstand surfaces: calcrete and organic-matter/evaporite facies association on a palimpsest Middle Jurassic landscape from Portugal[J],2015,323:66-91. |
APA | Azeredo, Ana C.,Wright, V. Paul,Mendonca-Filho, Joao,Cristina Cabral, M.,&Duarte, Luis V..(2015).Deciphering the history of hydrologic and climatic changes on carbonate lowstand surfaces: calcrete and organic-matter/evaporite facies association on a palimpsest Middle Jurassic landscape from Portugal.SEDIMENTARY GEOLOGY,323,66-91. |
MLA | Azeredo, Ana C.,et al."Deciphering the history of hydrologic and climatic changes on carbonate lowstand surfaces: calcrete and organic-matter/evaporite facies association on a palimpsest Middle Jurassic landscape from Portugal".SEDIMENTARY GEOLOGY 323(2015):66-91. |
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