Knowledge Resource Center for Ecological Environment in Arid Area
DOI | 10.1016/j.sedgeo.2017.09.002 |
Asymmetrical, inversely graded, upstream-migrating cyclic steps in marine settings: Late Miocene-early Pliocene Fish Creek-Vallecito Basin, southern California | |
Gong, Chenglin1,2; Chen, Liuqin2,3; West, Logan2 | |
通讯作者 | Gong, Chenglin |
来源期刊 | SEDIMENTARY GEOLOGY
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ISSN | 0037-0738 |
EISSN | 1879-0968 |
出版年 | 2017 |
卷号 | 360页码:35-46 |
英文摘要 | Cyclic steps are ubiquitous in modern sedimentary environments, yet their recognition remains sparse in the rock record. Here, we interpret three sets of undulating backsets CI to 3) recognized in the late Miocene-early Pliocene Latrania Formation in the Anza-Borrego Desert, the Fish Creek-Vallecito Basin, southern California, USA as the first cm- to dm-scale outcrop record of cyclic steps, based on asymmetrical cross-sections, upstream migration, and inversely graded laminae. Upstream migration and asymmetrical cross-sections of bacicsets and concomitant backset laminae are attributed to supercritical-to-subcritical flow transitions through weak hydraulic jumps, which are composed of: (i) thin (tens of centimetres) and slower (reported as flow velocities ((U) over bar) of 0.45 to 1.45 m s(-1), with mean value of (U) over bar = 0.89 m s(-1)) subcritical (represented by internal Froude numbers (Fr) of 0.67 to 0.99, with mean value of Fr = 0.84) turbidity currents on the stoss sides, and (ii) thin (tens of centimetres) and faster (reported as (U) over bar of 0.99 to 4.03 m s(-1), with mean value of (U) over bar = 2.24 m s(-1)) supercritical (represented by Fr of 1.84 to 3.07, with mean value of Fr = 2.42) turbidity flows on the lee sides. The inversely graded laminae in the troughs of backsets are 2 to 5 cm thick, and consist of two discrete divisions: (i) 1 to 2 cm thick, lower finer-grained divisions made up of parallel laminated siltstones, overlain by very fine-to fine-grained sandstones, and (ii) 2 to 3 cm thick, upper divisions composed of medium- to coarse-grained sandstones, with sporadic occurrence of subrounded pebbles. These inversely graded laminae are related to stratified, collisional and/or frictional traction carpets under conditions of high fall-out rates. Due to the poor preservation potential of cyclic steps, the rock record of cyclic steps is generally considered to be rare. The present outcrop-based study presents a detailed analysis of sedimentary facies, growth patterns, and flow dynamics of marine cyclic steps, thereby contributing to better understand architectural styles and lithological properties of cyclic steps in the geological record. (C) 2017 Elsevier B.V. All rights reserved. |
英文关键词 | Cyclic steps Supercritical-to-subcritical flow transitions Weak hydraulic jumps Inversely graded laminae Traction carpets Fish Creek-Vallecito Basin |
类型 | Article |
语种 | 英语 |
国家 | Peoples R China ; USA |
收录类别 | SCI-E |
WOS记录号 | WOS:000413885600003 |
WOS关键词 | FORE-ARC BASIN ; TURBIDITY CURRENTS ; SUBMARINE CANYONS ; DENSITY FLOWS ; SUPERCRITICAL FLOWS ; MONTEREY CANYON ; HYDRAULIC JUMPS ; SEDIMENT WAVES ; SALTON TROUGH ; SEA-FLOOR |
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/2XILL650/202398 |
作者单位 | 1.China Univ Petr, Coll Geosci, Beijing 102249, Peoples R China; 2.Univ Texas Austin, Dept Geol Sci, Jackson Sch Geosci, Austin, TX 78712 USA; 3.East China Univ Technol, Sch Earth Sci, Dept Geosci, Nanchang 330013, Jiangxi, Peoples R China |
推荐引用方式 GB/T 7714 | Gong, Chenglin,Chen, Liuqin,West, Logan. Asymmetrical, inversely graded, upstream-migrating cyclic steps in marine settings: Late Miocene-early Pliocene Fish Creek-Vallecito Basin, southern California[J],2017,360:35-46. |
APA | Gong, Chenglin,Chen, Liuqin,&West, Logan.(2017).Asymmetrical, inversely graded, upstream-migrating cyclic steps in marine settings: Late Miocene-early Pliocene Fish Creek-Vallecito Basin, southern California.SEDIMENTARY GEOLOGY,360,35-46. |
MLA | Gong, Chenglin,et al."Asymmetrical, inversely graded, upstream-migrating cyclic steps in marine settings: Late Miocene-early Pliocene Fish Creek-Vallecito Basin, southern California".SEDIMENTARY GEOLOGY 360(2017):35-46. |
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