气候变化领域集成服务门户(CCPortal): Architectural evolution of a mixed-influenced deltaic succession: Lower-to-Middle Ordovician Armorican Quartzite in the southwest Central Iberian Zone; Penha Garcia Formation (Portugal)

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DOI	10.1007/s00531-020-01915-8
	Architectural evolution of a mixed-influenced deltaic succession: Lower-to-Middle Ordovician Armorican Quartzite in the southwest Central Iberian Zone; Penha Garcia Formation (Portugal)
	Bayet-Goll A.; de Carvalho C.N.
发表日期	2020
ISSN	14373254
起始页码	2495
结束页码	2526
卷号	109 期号:7
英文摘要	Facies stacking patterns and stratigraphic relationships resulting from the interaction of fluvial and wave processes, along with the paleoshoreline orientation and key surfaces, are essential to understand the temporal changes in the rate of change of accommodation space (A) versus sediment supply rate (S). High-frequency sea-level fluctuations in deltaic systems are controlled by changing accommodation and accumulation, which are explained mainly by autocyclic or allocyclic mechanisms. In deltaic systems, changes in the A/S ratio can be showed by significant variations of the internal facies architecture and the external morphology of the delta complex. These criteria have been used to investigate the relationship between autocyclic and allocyclic processes on the architectural evolution of a mixed river- and wave-influenced asymmetrical delta during the Lower-to-Middle Ordovician in the southwest Central Iberian Zone, in Portugal. Relying on the sedimentary and ichnological characteristics, the herein defined Penha Garcia Formation is classified into two main groups of facies associations, which are interpreted as deposited in a mixed asymmetrical delta with a trend of along-strike variations between wave-dominated strandplain (updrift) and river-dominated deltaic settings (downdrift). The vertical stacking arrangements of parasequences led to the identification of five depositional phases (I to V). Detailed analysis of geometry and internal architecture of the depositional phases along depositional strike shows a highly variable number of shallowing-upward cycles and facies thicknesses/heterogeneity on the updrift and downdrift side due to changes in rates of accumulation and hydrodynamic processes. The stratigraphic architectural style of the depositional phases I to V, and the trend of the total regressive ascending shoreline trajectory, are evidences that the deposition of the Penha Garcia Formation likely took place under an increasing rate of accommodation due to long-term relative sea-level rise (allocyclic), and high subsidence rates coupled with an increase in sediment supply, which could have been locally amplified by compaction of the prodelta-related muddy beds (autocyclic). This study suggests that in evaluating the autocyclic mechanisms on deltaic processes in short-time scales, there is a remarkable difference in terms of its impact on the internal variability of the depositional phases, both in the updrift and downdrift regions of mixed-influenced asymmetrical deltas. The most important reasons for the different effects of autocyclic mechanisms can be related to facies-dependent differential compaction or local changes in subsidence pattern, differences in the proximity to the distributary channel system, and differences in the influence of intrinsic processes of storm and wave reworking (wave-sweeping mechanisms). © 2020, Geologische Vereinigung e.V. (GV).
英文关键词	Allocyclic; Architectural evolution; Armorican Quartzite; Autocyclic; Central Iberian Zone; Mixed-influenced delta; Penha Garcia Formation
语种	英语
scopus关键词	architecture; delta; deposition; facies analysis; ichnology; Ordovician; quartzite; sea level change; sediment transport; stratigraphy; subsidence; Central Iberian Zone; Portugal
来源期刊	International Journal of Earth Sciences
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/147618
作者单位	Department of Earth Sciences, Institute for Advanced Studies in Basic Sciences (IASBS), P.O. Box 45195-1159, Zanjan, Iran; Geology Office of Idanha-a-Nova, UNESCO Naturtejo Global Geopark, Avenida Joaquim Morão, Idanha-a-Nova, 6060-101, Portugal; Instituto D. Luiz, University of Lisbon, Campo Grande Edifício C1, Piso 1, Lisbon, 1749-016, Portugal
推荐引用方式 GB/T 7714	Bayet-Goll A.,de Carvalho C.N.. Architectural evolution of a mixed-influenced deltaic succession: Lower-to-Middle Ordovician Armorican Quartzite in the southwest Central Iberian Zone; Penha Garcia Formation (Portugal)[J],2020,109(7).
APA	Bayet-Goll A.,&de Carvalho C.N..(2020).Architectural evolution of a mixed-influenced deltaic succession: Lower-to-Middle Ordovician Armorican Quartzite in the southwest Central Iberian Zone; Penha Garcia Formation (Portugal).International Journal of Earth Sciences,109(7).
MLA	Bayet-Goll A.,et al."Architectural evolution of a mixed-influenced deltaic succession: Lower-to-Middle Ordovician Armorican Quartzite in the southwest Central Iberian Zone; Penha Garcia Formation (Portugal)".International Journal of Earth Sciences 109.7(2020).