FACIES MODELS FOR DEEPWATER GRAVITY- DIS-PLACED DEPOSITS IN ANCIENT MARINE BASINS, SOUTH CHINA
-
摘要: 通过对华南地区诸多海相盆地深水沉积物的详细解剖,识别出一个由重力搬运沉积形成的完整岩类系列,包括孤立岩块、滑动滑塌和重力流沉积三个基本端元大类。这些重力流沉积以不同的型式组合构成了三大类七亚类各具特征的深水沉积体系。Ⅰ陆源碎屑体系包括(1)海底扇和(2)轴向搬运沉积亚体系。Ⅱ碳酸盐体系包括(1)碳酸盐缓坡,(2)沟槽型碳酸盐斜坡和(3)碳酸盐陡坡。Ⅲ混合物源体系包括(1)碳酸盐斜坡体系与陆屑海底扇组合;(2)碳酸盐斜坡体系与火山碎屑重力流轴向搬运沉积体系。Abstract: A spectrum of gravity-displaced deposits from isolated rock blocks through slides and slumps to various kinds of gravity flow sediments can be recognized through anatomizing deepwater deposits in many marine basins of South China.Their different association reflects the different types of sedimentary system to which they belong and their different distribution in each given system.Based on major sources those systems related lo gravity-displacement are divided into three categories: (1) gravity-displaced clastic system: (2) grivi-ty-displaced carbonate system; and (3) gravity displaced mixing sediment system.Category 1 includes two subdivisions of submerine fan and axial-transported system. In terms of the slope gradient of carbonate platform margin category 2 provides three kinds of the models or systems. 1) Ramp-type: besides some thin turbidites and small slumps, its sedimentary characteristics are the dominant fine deposits from sediment rain and the lack of gravity flow deposits containing the materials derived from shallow platform although reefs or mounds and shoals or ooids bands can exist in upper slope or outer shelf. 2) Middle slope gradient- type: it consists of four parts: a) a steeper bypass zone- upper slope which is indicated by periplatform fine sediments deposited in areas between numerous small channels that are perpendicular to the trend of the slope arid are filled with coarse gravity-displaced deposits; b) a gentle middle and lower siope which is the most important site for almost all kinds of gravity-displaced deposits; c) a slope toe in which channelized deposits disappear obviously but are replaced mainly by finer and thiner sheet beds of gravity flow depostits, and the combination of these beds constitutes a banded zone parallel to the trend of the slope along the slope toe; and d) a flat basin floor in which only fine deposits from sediment rain are developed and occasionally interlayered with thin turbidites. 3) Steep slope-type: it includes a very steep slope and a very adjacent fiat basin floor, and is characterized by the lack of channelized deposits and the development of gravity flow calcirudite sheets in large scale. In category 3 the framework of sedimentary systeem is the most complex and commonly is a combination of several subsystems, including: 1) carbonate slope system and clastic submarine fan; and 2) carbonate slope system and pyroclastic gravity flow axial-transported system.
-
[1] (1)王一刚,1986,黔南桂西早二叠世大陆斜坡碳酸盐重力流沉积。沉积学报,第4卷,第2期。
(2)孙枢、李继亮,1984,我国浊流与其它重力流沉积研究进展概况和发展方向问题当议,沉积学 报,第2卷,第4期。
(3)刘宝君、张锦泉、叶红专、1987,黔西南中三叠世陆棚一斜坡沉积物征,沉积学报,第5卷,第2期。
(4)杨振强,1985,湖南道县宁远一带中泥盆统棋梓桥组中台地前缘斜坡异地碳酸盐沉积。沉积学报,第3卷,第4期.
(5)高振中,段太中,1985,湘西黔东寒武纪深水碳酸盐重力沉积。沉积学报,第3卷,第3期。
(6)高振中,刘怀波,1983,十万大山盆地北缘早三叠世碳酸盐重力流及其地质意义,石油与天然气 地质,第4卷,第1期。
(7)高振中、段太中,1986,滇西北泥盆纪海槽中的陆源碎屑海底扇及坡脚碳酸盐异地沉积,天然气地质,第7卷,第4期。
(8)段太中,曾允孚、.高振中,1988,根据沉积历史分析华南古大陆边缘的板块构造,石油与天然气地质,第9卷,第4期。
(9)候方浩,黄继祥,1984,南盘江断陷区二、三叠系的火山碎屑浊积岩-种独特的尤海底扇浊流沉积模式,沉积学报,第2卷,第4期,
(10) Bouma, A.H,1962, Sednnentology of Some flysch deposits: Agraphlc approach to furies in-terpretron, Elsevier, A mstcrdam.
(11)Dolt, R H,Jr,1963, Dynamics of subaqueous gravity deposltiona
(12)Lowc. D. R.,1982, Special reference to the deposits of high- densy turbnlny crurrents.Jour.Sed.Petrology.Vo1.52 p.279-297.
(I 3)Miall, A. D. 1984, Principles of Sedimentary basin analysis. Spring-Verlag. Now york Berlm Heuelberg Tokyo
(14)ulhns, H T., et al、1984, Anatomy of modern open-ocean carbonate slope Northern LUR 1e Bahamn Bank, Sednnentology, 31: 141-168.
(15) Muhns, H T 1986, ,hook, H.E., ('arbonate apron models: AlternaUves to the ,ubmanm I, nmodel for paleoenvitonmental analysis and hydrocarbon exploration. Sed.Geology V -48 p 37-79,.
(16) Mudleton, G.V. and Hampton, M.A.,1976, subaqueous sediment transport and depositmn by sediment gravity flows. In: Marine sediment Transport and Environmental Managemml(rd D.J Stanley and D.J.P.Swift),John Wiley, New York
计量
- 文章访问数: 464
- HTML全文浏览量: 10
- PDF下载量: 510
- 被引次数: 0