遗迹组构的精细分析功能及其应用:第15届国际遗迹组构专题研讨会综述

第15届国际遗迹组构专题研讨会于2019年4月26日至5月9日在捷克首都布拉格顺利召开。从口头报告、展板、野外地质考察及专题讨论等方面可以得出遗迹学理论取得的新进展及其应用主要集中于4个方面: (1)遗迹组构内涵的外延和精细分析功能的完善,为沉积微环境分析、成因地层学解译和油气水储集层的精细表征提供了科学的理论基础和实用的工作方法;(2)遗迹化石在古生态、古气候等研究中的应用已成为遗迹学的重要工作领域,旨在通过研究古生物丰富的行为学、埋藏学特征,解译(古)生物与沉积物的相互作用,揭示遗迹化石发育段的古生态与古气候特征,进而搭建古生物学、沉积学和层序地层学之间的桥梁;(3)遗迹化石在重大地质事件研究方面具有重要应用,特别是为研究生物大灭绝后生态恢复期因没有矿化骨骼而无法保存为实体化石的生物提供了良好的信息载体,同时也为研究生物复苏期生态系统状况和大地构造-沉积环境条件提供了宝贵的线索;(4)新技术和新方法正在遗迹学研究中得到广泛应用,必将推动遗迹学理论的进一步完善和生产应用的快速发展。     

21世纪遗迹学热点与前沿:第14届国际遗迹组构专题研讨会综述

第14届国际遗迹组构专题研讨会于2017年4月29日至5月2日在中国台北台湾大学顺利召开。从会议口头报告、展板、会间和会后野外地质考察以及交流讨论可以看出遗迹学热点与前沿:(1)遗迹化石的系统分类将一直是遗迹学家努力的方向,旨在为古生物学研究提供丰富的行为学资料,并为沉积学、古生态学等研究提供科学、客观和简便的遗迹分类学框架;(2)遗迹组构分析在沉积学中的深入应用,能提供大量传统沉积学、地球化学分析所无法揭示的生物学信息;(3)重大地质事件的遗迹学响应以及遗迹化石的演化古生态学为地质—生命突变期研究提供了独一无二的新素材;(4)地微生物学与遗迹学的结合进行了初步有益尝试;(5)特殊化石行为如求偶行为的报道扩大了深时行为类型;(6)定量形态表征和统计分析是遗迹学研究精细化和定量化的重要途径,通过遗迹组构分析来定量刻画沉积环境因子是遗迹组构研究的重要前景方向。     

连结过去、现在和未来的遗迹组构研究:第13届国际遗迹组构专题研讨会综述

第13届国际遗迹组构专题研讨会于2015年5月14日—21日在日本高知大学召开。从会议报告、展板和野外地质考察可以看出:(1)遗迹化石的演化古生态学和复杂遗迹化石的古生态学、埋藏学精细分析将是未来遗迹学的研究热点;(2)遗迹化石的正确分类命名及其形态功能和古环境分析依然是遗迹学的基础和主要内容;(3)新遗迹学展示了巨大的生命力,成为了将今论古的重要钥匙;(4)三维动画模拟未来将推动遗迹学、生态学的科学普及;(5)遗迹组构在油气勘探应用中已取得了重大的成果。学科交叉和高新技术测试方法、跨越多学科的思维路线将是遗迹学发展的重要推动力。     

遗迹学的研究现状与新进展--第8届国际遗迹组构专题研讨会综述

第8届国际遗迹组构专题研讨会于2005年2月17~23日在新西兰奥克兰大学召开。从会议报告、展板、论文摘要集和野外地质旅行可以看出: 遗迹化石正确的分类命名及其形态功能和生态环境再造仍然是遗迹学的基础和主要内容,常见和复杂遗迹化石的精细研究和重新解释将导致遗迹化石指示古环境和古生态意义的重大变革,遗迹化石特征的实验模拟和实证观测是定量解释造迹生物行为习性和生态环境意义的有效手段,许多鲜为人知或被忽略的问题和现象走进遗迹学家的视野, 陆相遗迹化石群落与遗迹组构研究有了新的进展,遗迹组构的岩心成像技术和三维模拟在油气勘探中正发挥越来越大的作用,学科交叉融合和高新技术测试方法的引进是遗迹学发展的重要推动力。     

辽河油田陆相遗迹组构类型及其环境解释

遗迹组构自Ekdale(1983）首次提出以来，其研究成果主要来自海相沉积，我国是世界上陆相沉积最为发育的地区之一，特别是能源勘探与开发积累了大量宝贵的岩心资料。这些钻孔岩心表面新鲜，垂向连续性好，有利于研究遗迹化石的垂向演化关系，本文在详细观察描述辽河油田古近系200口井岩心的遗迹化石资料基础之上，首次将陆相岩心遗迹组构划分为2类11种，通过古生态学与沉积学研究相结合，对每种遗迹组构的环境意义进行解释。     

豫西北奥陶系马家沟组三段遗迹组构及沉积演化规律

豫西北奥陶系马家沟组三段碳酸盐岩中遗迹化石丰富。在对野外露头实地观测的基础上,利用室内切片、薄片分析等对研究区奥陶系马家沟组三段遗迹化石、遗迹组构及沉积演化规律进行研究。结果表明:(1)研究区奥陶系马家沟组三段共鉴定出遗迹化石类型7属10种。(2)根据遗迹化石的分子组成、产状、共生关系、丰度与分异度以及生物扰动的程度,结合沉积学特征分析,共识别出遗迹组构4种:Psilonichnus遗迹组构主要发育在潮上带与潮间带上部(高潮坪)低能的沉积环境;Thalassinoides遗迹组构代表潮间带中-下部和台内滩等高能沉积环境;Helminthopsis遗迹组构反映局限碳酸盐岩台地内的潟湖和开阔台地内的滩间海等较低能的沉积环境。Helminthopsis-Chondrites遗迹组构揭示开阔碳酸盐岩台地中滩间海-台内洼地等非常低能的沉积环境。(3)建立了研究区马家沟组三段的层序地层格架,并在层序格架内对遗迹组构和沉积微环境的演化规律进行了研究,解译出研究区马家沟组三段经历了两次区域性的海侵—海退;综合岩石类型、岩石序列组合、沉积构造、生物化石、遗迹化石组合、遗迹组构等资料,建立了研究区奥陶系马家沟组三段各遗迹组构与沉积微环境的三维相模式。这对研究华北奥陶系沉积环境与沉积演化具有重要的借鉴意义。     

第9届国际遗迹组构专题研讨会综述*

第9届国际遗迹组构专题研讨会于2007年8月13—18日在加拿大卡尔加里大学召开。从会议报告、展板、论文摘要集和野外地质考察可以看出:自1983年遗迹组构概念提出以来,一些新思维、新方法的应用极大地拓宽了遗迹学的研究领域,其已经被广泛应用到地层学和沉积学的诸多领域,并随着油气的勘探与开发得到了迅速发展。海相、陆相遗迹组构分析及其在储集层沉积环境和高分辨率层序地层学精细研究中的应用仍然是当前遗迹学的主题,遗迹组构的CT成像技术和三维可视化模拟在地下水勘查和油气勘探中正在发挥越来越大的作用。     

中国遗迹学研究十年进展

近十年来,中国遗迹学的研究取得许多新进展和新认识,重要成果概述如下:(1)在显生宙海相和过渡相沉积中新识别出84个遗迹属和211个遗迹种,新建28种遗迹组合及26种遗迹组构;在中生代和新生代陆相冲积扇、河流与湖泊沉积中识别出44个遗迹属和107个遗迹种,新建22种遗迹组合及10种遗迹组构;(2)论述了寒武纪底质革命对早...     

琼东南盆地北部新近系三亚组遗迹组构特征及其沉积环境

琼东南盆地北部新近系地层厚度巨大,遗迹化石非常发育。在对7口取心井岩心详细观测的基础上,综合利用薄片分析、成像测井与相关实验等资料,对琼东南盆地北部新近系三亚组遗迹组构特征及其沉积环境进行了研究。结果表明:(1)琼东南盆地北部新近系三亚组共识别出遗迹化石14属,根据遗迹化石的类型、产状、丰度和分异度、扰动程度、生物潜穴之间的共生关系等,可划分出5种遗迹组构,其中OphiomorphaThalassinoides遗迹组构主要发育在临滨上部沉积环境中,Palaeophycus遗迹组构主要发育在临滨中部沉积环境中,Planolites-Thalassinoides遗迹组构主要发育在临滨下部沉积环境中,Phycosiphon-Planolites遗迹组构主要发育在浅海上部沉积环境中,Phycosiphon-Chondrites遗迹组构主要发育在浅海下部沉积环境中;(2)根据遗迹组构和测井相分析认为琼东南盆地北部新近系三亚组沉积环境为滨-浅海,三亚组一段的沉积环境为由滨岸向浅海过渡,而三亚组二段的沉积环境为浅海;(3)综合岩相、生物化石、遗迹组构、测井相和沉积微相分析结果,建立了琼东南盆地北部新...     

粤北晚泥盆世天子岭组遗迹组构及其环境解释

遗迹组构是由生物成因改造的沉积岩组构,它是物理过程和生物过程相互作用的产物。本文在广东韶关晚泥盆世天子岭组碳酸盐岩沉积中建立了4个遗迹组构,即反映局限台地或封闭海湾环境的Planolies montanus遗迹组构,反映台地潮下低能环境的Thalassinoides—Planolites遗迹组构,反映潮上-潮间环境的．Skolithos遗迹组构和受固底底质控制的Thalassinoides遗迹组构。对遗迹化石和生物扰动构造进行阶层分析,从中识别出受固底底质控制的遗迹化石Thalassinoides.sp,这类遗迹化石常常代表层序地层学中的重要界面。     

Linking invertebrate burrow distributions (neoichnology) to physicochemical stresses on a sandy tidal flat: implications for the rock record

Invertebrate burrow distributions (neoichnology) across a modern tidal flat are presented as an analogue for interpreting the ichnology of palaeo‐tidal‐flat successions. Burrow distributions are linked to physical and chemical (physicochemical) stresses to establish the main controls on the distribution of biosedimentary structures. Across the tidal flat, there is clear heterogeneity in both the diversity of traces and the intensity of burrowing. This heterogeneity reflects a myriad of physicochemical stresses, with the sedimentation rate dominating burrow distributions. Across all substrates, the total area occupied by organisms rarely exceeds 3% of the tidal‐flat surface, and is commonly <1%; this equates to a bioturbation index value of one. To reach bioturbation index values of two to six, sediments must be available to biogenic reworking and/or recolonization. With an increasing sedimentation rate, substrates are rapidly buried and re‐exposed, which limits the time when a substrate is available to colonization. For palaeo‐ichnological studies, this research presents several key results. (i) Burrow cross‐cutting relationships in tidal‐flat successions commonly reflect natural heterogeneities in the areal distribution of infaunal communities, rather than infaunal tiering. (ii) Ichnofabric analysis of palaeo‐tidal flats with a high sedimentation rate would yield fabrics that reflect heterogeneities in the areal distribution of infaunal communities rather than variability in the physicochemical stresses of the environment. (iii) The composite trace‐fossil assemblage of tidal flats cannot be attributed to a single ichnofacies, but instead comprises elements typical of multiple ichnofacies. (iv) The main controls on trace assemblages across tidal flats in fully marine settings are sedimentological and include the sedimentation rate and, to a lesser extent, grain size.     

Sub‐fossil Chironomidae as indicators of palaeoflow regimes: integration into the PalaeoLIFE flow index

The sub‐fossil head capsules of larval Chironomidae have been widely exploited as palaeoecological indicators of lentic ecosystems but their value in the interpretation of the evolution of lotic systems has been underutilised by comparison. Recent research has demonstrated that the remains of Chironomidae are abundant within fluvial sequences and that they offer a valuable record of channel change and floodplain evolution that may complement that derived from existing biological and sedimentological techniques. This paper demonstrates the use of Chironomidae in characterising the palaeoflow regime of a large mid–late Holocene floodplain palaeochannel (5470–4960 to 1530–1350 cal. a BP) of the River Trent (Derbyshire, UK). Using expert knowledge and published information regarding flow preferences, larval Chironomidae were incorporated into the PalaeoLIFE (Lotic‐invertebrate Index for Flow Evaluation) methodology. The results clearly demonstrate that the sub‐fossil record provided by Chironomidae can be used to characterise changes in the flow regime within palaeochannel sections. At the scale of the channel section, species‐ and generic‐level ecological associations can provide useful information regarding habitat characteristics, including the presence of instream vegetation, mineral substrates and woody debris. The ability to undertake environmental reconstruction and channel evolution history was significantly enhanced through the application of a multi‐proxy approach, by incorporating other aquatic insect groups (Trichoptera and Coleoptera) into the PalaeoLIFE metric, together with sedimentological data. Copyright © 2010 John Wiley & Sons, Ltd.     

Ichnological analysis of transgressive marine tongue in prograding deltaic system: Evidences from Ukra Hill Member, Western Kachchh, India

The Ukra Hill Member exposed only in Western part of Kachchh basin comprises of fossiliferous shales, limestones and glauconitic sandstones in between thick unfossiliferous sandstone. The present study documents abundance of trace fossil Teredolite, occurring as driftwood and bedload log ground as well as re-worked log ground from the basal part of the Ukra Hill Member. These Teredolite bearing horizons are underlain by coarse grained cross bedded sediment with monodominant Psilonichnus tubiformis, while abundant Gyrolithes cycloides along with Rhizocorallium irregulare, R. Jenense occurs in overlying horizons. Three ichnofabrics recognized within the Ukra Hill Member are inferred to represent near shore high energy conditions (Psilonichnus ichnofabric), transgressive condition with subsequent erosion (Teredolites Ichnofabric) and shelf environment (Gyrolithes-Rhizocorallium Ichnofabric). TheTeredolite bearing horizons also occurs with abundant belemnites Neohibolithes ewaldi, which is considered to be index fossil for the Early Aptian sediments. Thus, based on the ichnofabric analysis, the basal part of the Ukra Hill Member represents an Early Aptian transgressive event in Kachchh basin.     

Ichnofabrics and geometric configurations of Ophiomorpha within a sequence stratigraphic framework: an example from the Upper Cretaceous US western interior

Ichnofabric in the Upper Cretaceous Sego Sandstone and Anchor Mine Tongue of east-central Utah can be differentiated into two components: (1) discrete Ophiomorpha and (2) mottling and other trace fossils. The ichnofabric index method was employed to evaluate spatial variability of the ichnofabrics within depositional sequences and component systems tracts. Indices were logged for amount of bioturbation caused solely by Ophiomorpha (Oii) and that represented by all other biogenic features (Bii). Values of Oii> 1 are more pervasive in lowstand systems tracts compared to transgressive systems tracts. This is consistent with the predominance of marginal and nearshore marine, sand-dominated settings that are characteristic of lowstands, which are favourable habitats for colonization by Ophiomorpha producers. Ichnofabric index values vary both vertically and laterally within any given systems tract, reflecting differences in physical and biological parameters operating in the palaeoenvironment. These parameters include the total number and behaviours of organisms occupying the substrate, as well as substrate texture and grain size, and rates of sedimentation. The architectural style of Ophiomorpha was examined within five depositional facies: shelf, storm deposit, lower shoreface, shoreface, and estuarine. Inclinations of individual burrow elements were approximated relative to bedding planes, categorized as either vertical, inclined or horizontal, and then plotted on ternary diagrams. Based on the types of facies present, these results suggest that variations in the geometric configurations of Ophiomorpha are controlled primarily by physical energy levels, and the rate and nature of sedimentation. Results of this study have broad implications for understanding the physical factors affecting facies variability within sequences and systems tracts. When coupled with sedimentologic data, recognition of variations in the distribution of ichnofabrics and architectural style of Ophiomorpha can provide additional information useful for characterizing depositional environments, and therefore could be integrated with other basin analysis techniques to test and refine sequence stratigraphic interpretations.     

辽西北票地区义县组地层层序与化石层位

辽西北票地区义县组是一套中生代火山-沉积地层.义县组火山活动具有明显的旋回性特征,主要由下部基性-中基性火山喷发-沉积旋回和上部酸性、偏碱性火山活动旋回组成.具体可划分6个岩性段,自下而上分别为底砾岩段,基性、中基性火山岩段,湖相沉积岩段,酸性、偏碱性火山岩段,上部基性火山岩段和顶部砾岩段.义县组底砾岩段和基性、中基性火山岩段的沉凝灰岩中产有丰富的以鹦鹉嘴龙为主的古脊椎动物化石.湖相沉积岩段含有大量热河生物群化石,包括著名的中华龙鸟、孔子鸟和辽宁古果等珍稀化石,该层位记录了侏罗-白垩纪界限附近重大的生物演化事件.     

Climate change in Lake Baikal: diatom evidence in an area of continuous sedimentation

The presence of inhomogeneous sedimentation is acknowledged as being an important problem in palaeolimnological studies. Sediment records can be disturbed by erosional and redepositional events, which redeposit microfossils within a basin and may then lead to misinterpretations of fossil diatom assemblages. This study uses a combination of sedimentological tools, magnetic susceptibility measurements and high-resolution diatom analysis to show that a sediment core, BAIK80, taken in 345 m water depth from a shoulder region in the North Basin of Lake Baikal, is free of disturbances. Our results confirm that the sediment record is consistent and continuous for the uppermost sediment. Consequently, the fossil diatom data can be used to establish a continuous record of past climate variability over approximately the past 1300 years. Distinct changes occur in downcore abundances of endemic taxa Aulacoseira baicalensis and Cyclotella minuta, and principal components analysis (PCA) indicates a gradual transformation of taxa over the past 1300 years. These changes are likely to be related to climate, although definite links still have to be established. Received: 15 December 1998 / Accepted: 13 September 1999     

Transport, sorting, and reworking of late Wisconsinan plant macrofossils from Lake Erie, Canada

Stratigraphic, sedimentological, and plant macrofossil studies on proglacial lacustrine and deltaic sequences dating from the Mackinaw Interstadial on the north shore of Lake Erie, Canada, indicate long-distance transport, selective sorting and reworking of the plant fossils. Transport, sorting, and reworking may make detailed paleoclimatic indices irrelevant and may account for incongruent phytogeographic indicators in the fossil assemblage. Details of the stratigraphic and sedimentological setting of the study site and the state of preservation of the fossils should be considered more carefully as aids to the interpretation of macrofossil assemblages.