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1、1 引言31.1 生物礁问题31.2 生物礁和碳酸盐泥丘的构造分类42 地质学中生物礁的概念52.1 有机生物礁（Organic reefs）52.1.1 生物丘和生物层62.1.2 生物礁和滩62.1.3 建隆和地层礁72.1.4 丘：有机丘（organic mounds）、碳酸盐丘、礁丘72.1.5 胶结物礁82.1.6 构造（Structure）、相互依赖的生物集团（Guilds）和生物建筑体（Bioconstrucations）92.2 碳酸盐泥丘92.3 微生物礁112.4 生物礁岩石分类体系(Reef rock classification)122.5 生物礁大小和地势起伏143
2、过程、组成和构造（Processes, components, and structure）163.1 生物礁过程163.1.1 建设性过程163.1.2 破坏作用过程173.2 生物礁构成和MSC图解(Reef components and MSC diagrams)193.2.1. 沉积构成（Sedimentary components）203.2.2. MSC图解（MSC diagrams）213.3 生物礁构造（Reef structure）214. 生物礁和环境（Reefs and environment）254.1. 低和高能生物礁（Low and high energy reef
3、s）254.2. 分带和序列（Zonation and succession）265. 构造分类：有机生物礁（Structural classification: organic reefs）265.1 基质支撑的生物礁（Matrix-supported reefs）275.1.1 聚合的微生物礁（Agglutinated Microbial Reefs）275.1.2 丛状礁（Cluster Reefs）295.1.3 体节状生物礁（Segment Reefs）355.2 骨架支撑的生物礁365.2.1 骨架生物礁（Frame Reefs）365.3. 胶结物支撑的生物礁435.3.1. 胶
4、结物生物礁436 构造分类体系：碳酸盐泥丘486.1. 低起伏碳酸盐泥丘（Low Relief Carbonate Mud Mounds）496.2 高起伏碳酸盐泥丘（High Relief Carbonate Mud Mounds）516.2.1. 颗粒沉积物536.2.2. 早期石化作用（Early lithification）546.2.3. 微生物过程（Microbial processes）546.2.4 层状晶洞（Stromatactis）556.2.5 碳酸盐泥丘的多成因（Combined origins of carbonate mud mounds）556.2.6. 现代相似
5、物（Modern analogues）567 结语56Appendix A. Original definitions and early usage of some previous terms58Appendix B. Definitions introduced or refined here61生物礁和碳酸盐泥丘的构造和组成：概念和分类Robert Riding. Structure and composition of organic reefs and carbonate mud mounds: concepts and categories. Earth-Science Revi
6、ews, 2002, 58: 163231. (ridingcardiff.ac.uk )摘要：在这里被定义为“由固着生物形成的而且本质上为原地的钙质沉积”，生物礁是一种具有漫长地质历史的多样且复杂的构造。关于生物礁的分类一直是一个激烈争论的话题，争论的焦点常常集中在许多主观特征之上，这些特征包括抗浪性、区别“第一（原生）”和“第二（次生）”礁的定性描述的努力等。相反，在这里则主要集中在沉积支撑类型的客观特点之上，即主要区分该类沉积的沉积构成。（Defined here as essentially in place calcareous deposits created by sessile
7、 organisms, Organic Reefs are diverse and complex structures with a long geological history. Their classification has been the subject of fierce debate, often characterized by reliance on subjective features such as wave-resistance and qualitative attempts to discriminate between first and second cl
8、ass reefs. In contrast, emphasis is here placed on the objective characteristic of the type of sedimentary support, which largely determines the sedimentary composition of the deposit. ）建设性沉积过程主要产生三大类沉积组分：基质（M），本质上为原地的骨架（S），以及孔穴/胶结物（C），它们的比例可以用三角图解来加以图示。不管是作为特性还是共性，这些组分也为生物礁提供了结构支撑。以这些组成和结构为基础，就可以识别
9、出生物礁的三大类型：（1）基质支撑的生物礁（凝聚微生物礁，丛状生物礁，体节状生物礁）；（2）骨架支撑的生物礁（骨架礁）；（3）胶结物支撑的生物礁（胶结物礁）。（Constructional and depositional processes result in three principal sedimentary components: matrix (M), essentially in place skeletons (S) and cavity/cement (C), whose proportions can be represented on MSC triangular plo
10、ts. Separately or together, these components also provide the structural support for the reef. On these compositional and structural bases, three main categories of Organic Reef are recognized: (1) Matrix-supported reefs (Agglutinated Microbial Reefs, Cluster Reefs, Segment Reefs), (2) Skeleton-supp
11、orted reefs (Frame Reefs), (3) Cement-supported reefs (Cement Reefs).）凝聚微生物礁（Agglutinated Microbial Reefs）：由于沉积颗粒的微生物捕获作用而具有纹理状、凝块状和隐晶质组构，原地骨屑和大型原生孔穴较为稀少，早期胶结作用可能提供了另外的支撑，地势起伏受到那些为增生面提供沉积物的水流的一些必要条件的限制。（Agglutinated Microbial Reefs: possess laminated, clotted, or aphanitic fabrics created by microbi
12、al trapping of particulate sediment; in place skeletons and large primary cavities are rare; early cementation may provide added support; topographic relief is limited by the need for currents to provide sediment to accreting surfaces.）丛状生物礁（Cluster Reefs）：这是一种与本质上原地的骨屑呈相邻产出的而不是直接产出的骨架礁，从而产生基质支撑，以相对
13、较高的基质/骨架比例以及骨架外早期胶结物的较小体积为特征。沉积物的捕获作用是骨架生长的一个重要的必然结果，而且丛状礁生物能容纳松散沉积物。骨架构造的缺乏限制了该类生物礁的地势起伏，因此，丛状礁只能达到一定的空间发育程度，而且在生物礁体内部还会发育层理。紧密型丛状生物礁往往具有一个分隔开的骨架单元（unit-distance apart），分隔型丛状生物礁常常具有两个以上的骨架单元；随着骨架分割程度的增加会逐渐变为水平-底生物群落。（Cluster Reefs: skeletal reefs in which essentially in place skeletons are adjacent
14、, but not in contact, resulting in matrix support; characterized by relatively high matrix/skeleton ratios and low volumes of extra-skeletal early cement. Sediment trapping is an important corollary of skeletal growth and Cluster Reef organisms are tolerant of loose sediment. Absence of framework li
15、mits the topographic relief that Cluster Reefs can attain relative to spatial extent, and may permit bedding to develop within the reef. Close Cluster Reefs have skeletons up to 1 unit-distance apart. Spaced Cluster Reefs have skeletons more than 1, and up to 2 unit-distances apart; with increasing
16、separation of skeletons they grade to level-bottom communities.）体节状生物礁：这是一种基质支撑的生物礁，其中与骨架相邻，或者与骨架直接接触，但是多呈节状，而且主要是准原地的。基质较为丰富，但早期胶结物较少。在与强烈的生物礁之上的沉积物产生作用响应的过程中可以发育成中等的地势起伏程度。（Segment Reefs: matrix-supported reefs in which skeletons are adjacent, and may be in contact, but are mostly disarticulated a
17、nd mainly parauthochtonous. Matrix abundance is high, and early cement relatively low. Moderate relief can develop in response to intense on-reef sediment production.）骨架生物礁：生物骨架礁是指那些本质上原地的生物骨架（包括钙化的微生物）直接接触的生物礁，以较高的骨屑/基质比例为特征。骨架支撑使其生长在地层之上，不受胶结作用和颗粒沉积作用的控制。同时，由于局部的遮蔽空洞的产生，骨架支撑更有利于早期胶结物的形成。起伏程度和早期石化作
18、用会促使边缘碎屑岩块的形成。骨架形状和定向性用于区别以下特征：锥状/棒状、树形状、穹窿状以及纹层状骨架。这些不同形状的骨架也可能是空的，也可能是填充的。空的骨架礁：在生物礁生长的早期阶段孔洞是空的，而且被隐秘的结壳状生物、早期胶结物、以及间沉积物占据；暴露的估价会有利于内部石化。填充的骨架礁：骨架间的空间，在生物礁的生长过程中常常被表面沉积物准同生封闭。（Frame Reefs: skeletal reefs in which essentially in place skeletons (including calcified microbes) are in contact; charac
19、terized by relatively high skeleton/matrix ratio. Skeletal support enables them to raise themselves above the substrate independently of cementation and particulate sedimentation. Simultaneously, by creating partly open shelter cavities, skeletal support may facilitate early cementation. Both relief
20、 and early lithification promote marginal talus formation. Skeletal shape and orientation distinguish: conical/stick-like, dendritic, domical, and laminar frames. Each of these may be open or filled. Open Frame Reefs: cavities remain open during the early stages of reef growth and are occupied by cr
21、yptic encrusters, early cements and internal sediment; exposed skeleton encourages endoliths. Filled Frame Reefs: inter-skeletal spaces penecontemporaneously occluded by surficial sediment during reef-growth.）。胶结物礁：生物礁由本质上属于原地的生物的胶结物作用所形成。胶结物提供了强度和体积，这与骨架生长较为类似，而且可以形成在非骨架以及骨架生物之上。（Cement Reefs: reef
22、s created by cementation of essentially in place organisms. Cement provides strength and volume, mimicking skeletal growth, and can form on non-skeletal as well as skeletonized organisms.）非骨骼胶结物生物礁：实质上由原地骨骼生物的同沉积胶结作用所形成。该作用过程可以将那些保存潜力较低的软沉积物转变成坚硬的石化体：如河流和湖泊中的钙华胶结物生物礁（Tufa Cement Reefs(phytoherms)）以及
23、与热泉相关的可能的灰华胶结物生物礁（Travertine Cement Reefs）。如果生物是骨架状的，同沉积胶结作用将形成另外的强度和稳定性，也就是说，形成丛状的或骨架状的生物礁，即骨架-胶结物礁。胶结物礁表现出了胶结物、基质和骨架之间的一个复杂关系。（Non-skeletal Cement Reefs: created by synsedimentary cementation of essentially in place non-skeletal organisms. This converts a soft deposit with relatively poor preserva
24、tion potential into a rigid lithified mass: e.g., Tufa Cement Reefs (phytoherms) in rivers and lakes and possibly Travertine Cement Reefs associated with hot springs. If the organisms are skeletal, synsedimentary cementation imparts extra strength and stability to what otherwise would be a Cluster o
25、r Frame Reef, and results in SkeletonCement Reefs. Cement Reefs exhibit complex relationships between cement, matrix and skeletons.）。凝聚状微生物礁、丛状和体节状生物礁在组构上较为简单，原生地势起伏程度较低，而且有时还具有层理。骨架生物礁（包括微生物形成的微骨架）以及胶结物生物礁常常是非层理性的，组构复杂，而且具有较高的地势起伏程度（Agglutinated Microbial, Cluster and Segment reefs tend to be struc
26、turally simple, have low primary relief, and may show bedding. Frame (including microbial Microframe) and Cement Reefs tend to be unbedded, structurally complex, and can have high relief.）。碳酸盐岩泥丘：具有一定地势起伏程度或多或少发育叠层石、凝块石原地生物骨屑的以碳酸盐泥为主的沉积，则组成碳酸盐泥丘。低起伏碳酸盐泥丘特别薄；高起伏碳酸盐泥丘较厚，而且常常见到内部层理、滑塌构造、平底晶洞（stromatact
27、is）体系、陡边缘斜坡。生物礁是生物成因的、钙质的，而且几乎全部为原地生物所形成；碳酸盐泥丘可能是生物成因的，也可能是非生物成因的，而且成因上难以区别。（Carbonate Mud Mounds: carbonate mud-dominated deposits with topographic relief and few or no stromatolites, thrombolites or in place skeletons. Low Relief Carbonate Mud Mounds are typically thin. High Relief Carbonate Mud M
28、ounds are thick, and internal bedding, slumping, stromatactis cavity systems, and steep marginal slopes may be common. Whereas Organic Reefs are biogenic, calcareous, and are created by essentially in place organisms, Carbonate Mud Mounds can be organic and/or inorganic in origin and it can be diffi
29、cult to distinguish their origins）。1 引言1.1 生物礁问题生物礁，在本文被定义为本质上由原地固着生物所产生的钙质沉积，其发育历史较为漫长，从太古代的微生物礁到今天的珊瑚珊瑚藻礁。在漫长的历史演变过程中，参与造礁的生物以其不同的形式和造礁方式达到一个相同的结果：将这些造礁生物以其必要的强度维持在周围的沉积物中或沉积物之上，所谓的必要强度是指抗拒周围水体的运动所需要的强度。单个的固着生物也需要一定的地势起伏和稳定性；但是，在生物礁中整体的生物群落均得益于每一个个体的生长，最为有意义的是在同一地点得益于它们的祖先，将它们建筑为能面对沉积作用和水体运动的特殊筑积体
30、。（Reefs, defined here as calcareous deposits created by essentially in place sessile organisms, have a long history, from Archaean microbial reefs to present-day coralcoralline algae reefs. The organisms participating in reef formation through time have employed differing techniques to achieve essen
31、tially the same result: to maintain themselves at or above the level of the surrounding sediment with strength necessary to withstand ambient water movement. Solitary sessile organisms also need relief and stability, but in reefs entire communities benefit from the efforts of each individual, andsig
32、nificantlyfrom those of their predecessors on the same site, to establish themselves in the face of sedimentation and water movement.）。 生物礁是水生的生物沉积构造体，生态的差异确定了生物在各种环境中成礁的能力，不管水体是淡水还是海水、是深海还是浅海、宁静还是动荡、寒冷还是温暖(Fagerstrom, 1987)。当然，随着时间和空间的变化环境条件是变化的。相对海平面变化决定了浅海的范围和程度，包括堆积的沉积物以及温度和盐度的变化、波浪越过的的台地边缘相对宽窄的
33、变化程度。海水中碳酸钙的沉淀作用速率常常呈振荡性变化，该变化对微生物石化作用和早期胶结作用产生巨大影响，而这些作用加固生物礁又特别重要。环境条件的这些变化，与成交历史过程之中演化和灭绝事件一起，对生物礁类型的发育产生了主要的控制作用（Twenhofel, 1950; Newell, 1971, 1972; Heckel, 1974; Copper, 1974; James, 1978, 1983; James and Macintyre, 1985; Fagerstrom, 1987; James and Bourque, 1992; Tucker and Wright, 1990, pp.
34、190227; Kauffman and Fagerstrom, 1993; Webb, 1996; Wood, 1995, 1999; Kiessling et al., 1999）。随着时间的演变和环境条件的变化，其结果是生物礁极为复杂的变化。（Reefs are aquatic biosedimentary structures; ecological differences determine the abilities of organisms to build reefs in conditions where the water is fresh or marine, deep
35、or shallow, quiet or rough, cold or warm (Fagerstrom, 1987). Environmental conditions have, of course, varied through time as well as spatially. Relative sea-level changes have determined the extent of shallow seas, with accumulated sediment and temperature and salinity variations, relative to narro
36、w wave-swept platform margins. The rate of marine CaCO3 precipitation, influencing both microbial lithification and early cementation which are often crucially important in strengthening reefs, has also fluctuated. These changes in conditions, together with evolutionary and extinction events in the
37、history of reef-building organisms, have exerted major controls on the development of reef-types (Twenhofel, 1950; Newell, 1971, 1972; Heckel, 1974; Copper, 1974; James, 1978, 1983; James and Macintyre, 1985; Fagerstrom, 1987; James and Bourque, 1992; Tucker and Wright, 1990, pp. 190227; Kauffman an
38、d Fagerstrom, 1993; Webb, 1996; Wood, 1995, 1999; Kiessling et al., 1999). The result is a wide variety of reefs, adapted to different environments at different times.）。较为遗憾的是，类型的多样和复杂型使生物礁变得极为引人注目，从而也造成了建立生物礁清晰的定义和分类体系的若干困难（Heckel, 1974）。长期的研究表明分类太容易而使那些用来进行生物礁分类的基本属性常常落在视线之外（It has proved all too
39、easy to lose sight of the fundamental attributes that unite reefs.）。同时，关于区分不同类型生物礁的识别标志常常很少达成一致意见。长期以来，生物礁的讨论总是以缺乏清晰性、方向性和主观性的争论为特征（For too long, discussion of reefs was characterized by arguments that lacked clarity, direction and objectivity）。反过来看（In hindsight），似乎一个基本的错误是“又大又强的途径”（it appears that
40、a fundamental mistake was the “big and strong” approach）：生物礁的概念体系建立在表面形状特征之上，而不是其本质的定性特征。尤为特别的是，过多地关注现代实例常常使人误入歧途（the appeal of modern examples has been misleading）。如果理想的生物礁只是根据一些现代的六射珊瑚（scleractinian）珊瑚藻障壁礁来加以简单概括的话，那么许多地质历史时期的生物礁将会成为附属品（inferior）。（Unfortunately, the variety and complexity that mak
41、e reefs so interesting, have also made it difficult to establish clear definitions and classifications (see Heckel, 1974). It has proved all too easy to lose sight of the fundamental attributes that unite reefs. At the same time, there has been little agreement concerning recognition of differing re
42、ef categories. For too long, discussion of reefs was characterized by arguments that lacked clarity, direction and objectivity. In hindsight, it appears that a fundamental mistake was the big and strong approach: the tendency to base reef concepts on superficial quantitative rather than on essential
43、 qualitative features. In this respect particularly, the appeal of modern examples has been misleading. If the ideal reef were epitomized simply by the scale and grandeur of some modern scleractinian coralline barrier reefs, then many fossil examples would appear inferior.）。这种情况似乎可以比喻为否认一个螺旋桨驱动的小型飞机
44、与大型喷气式飞机的真正的相似性（Riding, 1976），尽管存在该基本事实，这些飞机均以其不同的方式完成同一个任务。如果所有的飞行器均只是通过与喷气式飞机的飞行能力来加以表的话，毫无疑问，在对“小型”飞行器进行分类时就会存在许多困难。一个合理的途径应该不是只是追寻一个涵盖各种意义的定义，不但包括喷流和螺旋桨驱动的飞行器，还包括滑翔机和气球。客观地区分这些飞行器的工作应该开始进行。该途径的目的是寻求一个宽广的对分类体系的外部限制，在其内部还可以识别亚类。相反，定义生物礁的许多努力似乎搞错了，一直在努力区分“好的”和“差的”生物礁（In contrast, attempts at reef d
45、efinition seem to have stumbled persistently by attempting to separate good and poor reefs）。（This can be likened (Riding, 1976) to denying the essential similarities between a small propeller-driven biplane and a large jetliner, despite the fact that, in their own ways, they fundamentally perform th
46、e same task. If all flying machines were assessed only by comparison with the capabilities of jet planes, there would inevitably be some difficulties in categorizing lesser aircraft. A rational approach should rather seek an inclusive definition, encompassing not only jet and propeller-driven craft
47、but also gliders and air balloons. The task of objectively distinguishing these different types of aircraft could then commence. This approach to classification seeks broad outer limits within which sub-categories can be recognized. In contrast, attempts at reef definition seem to have stumbled pers
48、istently by attempting to separate good and poor reefs.）。 对于生物礁的定义，“又大又强”的方法和途径的弱点是通过寻求“不适当的属性”作为定义特征的趋势变得越来越强烈。一个明显的例子是“抗浪性”。该概念的基本内容是，为了识别生物礁，生物礁首先应该具有抗浪性是极其有用的。当研究者努力去寻找古代生物礁是否具有抗浪性的时候，就开始产生怀疑了。然而，抗浪性概念的根本的不利条件不是该概念很难应用到古代实例，相对而言，任何保留在原地的沉积都是以不同的方式抗水流的，因为在其发育过程中首先面对的就是水流。（The weakness of the big
49、and strong approach to reef definition has been compounded by a tendency to invoke inappropriate attributes as defining characters. The obvious example is wave-resistance. The idea that a reef, in order to be recognized as a reef, must be or have been wave-resistant seemed useful at first sight. Doubt set in when workers tried to fin
