风暴沉积的遗迹学研究  

Ichnological Studies on Tempestites

作　　者：S.G.Pemberton 周志澄[2] J.Mac Eacher 

机构地区：[1]Department of Earth and Atmospheric Sciences Edmonton,AlbertaT6G2E3.Canada [2]中国科学院南京地质古生物研究所,南京210008 [3]Department of Earth Sciences Simon Fraser University,Burnaby,British Columbia,V5A156,Canada

出　　处：《沉积学报》2000年第4期489-494,共6页Acta Sedimentologica Sinica

基　　金：国家自然科学基金!(批准号 :49872 0 4 6);古生物所创新基金成果

摘　　要：遗迹化石正在证明其在鉴别和解释事件地层中的作用。风暴沉积含有一套混合的、与能量水平变化相适应的遗迹化石组合 ,两种不同的遗迹群落反映变化着的行为方式对生物所移居的两种连续的 ,但是单个性质不同的生境所作出的反应 :常住的或平常天气的遗迹群落可以作为一种稳定的底栖群落的代表 ,在这一群落里单个的居群达到或接近它们的承载能力 ;而周期性产生的风暴遗迹群落则代表着在一种不稳定的、生态环境恶化的、机械控制的环境下繁盛的机会主义生物的群落。典型的陆源碎屑的风暴沉积中的遗迹群落可以加拿大艾伯塔上白垩统卡迪组中的遗迹群落为例 ,而碳酸盐风暴沉积中的遗迹群落则可以中国华北地台东部上寒武统崮山组中的碳酸盐风暴沉积序列中的遗迹群落为例 ,本文详细介绍这两种类型的成因及结构、构造特点。Trace fossils are proving to be powerful tools for recognition and interpretation of event beds. Tempestites contain a mixed trace fossil assemblage that reflects fluctuations in energy levels. The two different ichnocoenoses reflect varying behavioral responses of the organisms colonizing two successive, individually distinct habitats. The resident or fair weather ichnocoenose can be considered representative of a stable benthic community, within which individual populations are at or near their carrying capacity. Periodic generation of the storm ichnocoenose, on the other hand, represents the flourishing of a community of opportunistic organisms in an unstable, high stress, physically controlled environment. The general succession, typical terrigenous tempestites represented by the tempestites in the Upper Cretaceous Cardium Fm. of Alberta , Canada , consists of (1)a fair weather resident trace fossil suite; (2) a sharp basal contact, with or without a basal lag; (3)parallel to subparallel laminations (reflecting hummocky or swaley cross stratification); (4)common escape structures; (5) the dwelling burrows of opportunistic organisms that colonize the unexploited storm unit; (6) gradational burrowed tops, representative of bioturbation resulting from subsequent burrowing by organisms from higher colonization levels; and (7) a fair weather resident trace fossil suite indicative of a return to quiescent conditions following abatement. Up to now, the ichnology in the carbonate tempestites has not been well studied and reported. The succession found in the Upper Cambrian Gushan Fm. from eastern North China Platform can be regarded as the typical carbonate tempestites . The succession includes the following parts (from bottom to top): (1) the trace fossils on the sole of the thin bedded limestone containing Phycodes, Thalassinoides, Palaeophycus and Planolites etc; (2) 1-2 cm thick muddy limestone or limestone with or without lamination; (3) the opportunistic trace fossils Diplocraterion, Arenicoli

关 键 词：风暴沉积 机会主义遗迹化石 均衡遗迹化石 幕式沉积事件 成因 结构 

分 类 号：Q911.28[天文地球—古生物学与地层学] P512.2[生物学—古生物学]