中国黔南晚石炭世生物灰泥丘生长发育特征研究

  本文关键词：黔南晚石炭世生物灰泥丘生长发育特征研究，由笔耕文化传播整理发布。

        中国南方晚石炭世海域广大,普遍发育了一套台地相碳酸盐岩,黔南是其中的一个代表性地区。该区碳酸盐台地浅水非常适宜生物生存,特别是底栖生物大量繁盛,生物造岩作用十分强烈。工作区晚石炭世地层发育较典型的生物泥丘,是开展生物灰泥丘研究的良好场所。本文对生物礁发育的地层开展了生物地层学研究工作,详细分析了产礁地层中蜒等生物群特征,通过对比研究,确定本区生物灰泥丘的产出层位为上石炭统上部地层,即马平组下部地层。黔南晚石炭世各种类型生物礁都发育在碳酸盐台地边缘,受台地边缘环境频繁变化的影响,不同类型生物礁发生明显的造礁群落取代,不同造礁群落建造不同的礁体。在台地边缘的不同环境,各种造礁生物也建造了不同礁体,尤其灰泥丘这一特殊生物礁更加特别。黔南晚石炭世地层中,蓝细菌是另一种重要的粘结生物,其作用方式有三种：粘结作用、粘结覆盖作用和缠结包绕作用,在工作区形成了大小不一的泥丘。生物灰泥丘在黔南地区分布较为广泛,尤其在路马寨较集中分布。根据其发育规模,作者将黔南生物灰泥丘分为3种类型,分别为大型泥丘、中型泥丘、小型泥丘。其特征如下：1组构特征外貌均呈穹形隆起,丘核均为泥晶灰岩,不显层理,均呈块状,且藻丝发育,偶见团块状粒状体(推测为藻颗粒)。丘顶与丘核无明显差异。丘两翼均为生物碎屑灰岩,主要为蜒碎屑灰岩。野外露头和显微镜下观察均可见晶洞,孔内为亮晶方解石充填。2岩石构成主要为泥晶灰岩及少量藻凝块岩,但骨骸颗粒较低而泥晶基质含量较高,表明为较深水的,水动力条件较弱的沉积环境。3古生物化石及其古生态同层位的滩相沉积富含多种生物,腕足类、蜒类、非蜒有孔虫、海百合、苔藓虫以及珊瑚类,与此形成鲜明对比的是,灰泥丘的生物丰度很低且种属单调。偶见单体珊瑚化石,薄片中见少量海百合、有孔虫以及蜒类化石。但在灰泥丘中发现大量的藻丝,是蓝细菌存在的遗迹。灰泥丘夹于灰色—灰黑色含化石丰富的灰岩之中。经过观察以及较为深入的研究,作者把工作区灰泥丘的生长发育过程分为三个阶段：基底的建立(发育期)、丘核的建立(繁盛期)、丘顶的建立(衰退期)对于生物灰泥丘建造的影响有很多因素：1海侵速率的影响研究发现：海侵速率与灰泥丘的增长速率是在大致相当的条件下进行的。在海水深度较小的条件下,当海侵速率略大于或等于灰泥丘的增长速率时,灰泥丘的生长空间大,以垂向加积为主,发育灰泥丘丘核;当海侵速率小于灰泥丘的增长速率时,灰泥丘由垂向加积生长转为侧向退积生长。在海水深度较大的情况下,当海侵速率小于或等于灰泥丘的增长速率时,利于菌、藻类等微生物繁殖,发育灰泥丘丘核;当海侵速率大于灰泥丘的增长速率时,海水深度变为不利于菌、藻类等微生物繁殖。灰泥丘的增长受到限制,泥晶凝块间被层纹状、网状泥灰质、灰泥质所分隔;当海平面波动适合于菌、藻类微生物繁殖时,便又开始发育泥丘丘核。2海水深度和阳光照射的影响在研究区发现,灰泥丘无明显的障积作用,丘两翼无明显差异,且灰泥颗粒细小,主要为泥晶灰岩和微晶灰岩,骨骸颗粒和非骨骸颗粒少,证明研究区灰泥丘的生存水动力条件较弱。灰泥丘内生物量极少,且种属单一,个体小。证明灰泥丘发育的水深不适合珊瑚等需要光照和大量养料的生物生存发展。根据以上分析,证明研究区灰泥丘的发育环境应为较深水的水动力条件较弱的透光沉积环境。当水深,水动力条件适合造丘微生物的生长和繁殖的时候,微生物开始大量繁殖,并且分泌粘液粘结水体中的钙质及生物碎屑。随着海平面的抬升,水动力条件的加强,微生物的生长繁殖受阻,灰泥丘的建造速度减慢。当海平面再度升高,水动力条件再度加强,造丘微生物停止生长,灰泥丘生长终结。3水温的影响许多学者都认为灰泥丘是通过微生物造岩作用而形成的,而且,在现代湖泊中发现了由蓝细菌的生命活动所形成的灰泥沉积物及灰泥丘。灰泥丘的形成被认为是从生物薄膜触发碳酸钙沉淀开始的。蓝细菌的适宜生存的温度为较温暖的环境。随着温度的降低,蓝细菌的代谢速率降低,致使蓝细菌分泌的粘液减少,使灰泥丘的生长速率减慢。当温度降低到某个临界值时,蓝细菌代谢停止,进而灰泥丘生长停止。这种蓝细菌的遗迹在工作区的灰泥丘中也有所发现(充当造丘生物),因此海水水温也是控制灰泥丘生长的重要因素之一。综上所述,灰泥丘的建立受到多方面因素的影响,只有在适合其生长发育的环境中它才能生长发育至繁盛。通过与世界Waulsortian丘进行对比研究发现,黔南地区所发育的灰泥丘与Waulsortian丘具有明显的差异,因此确定黔南地区所发育的灰泥丘并非Waulsortian相,是石炭纪特殊的灰泥构造。

    The sea area of south China in late Carboniferous is large,it develops a series of platform facies carbonate,The south Guizhou province is one of the typically area.The carbonate platform with low water in this area is feasible for life surviving,especially for the benthos blooming,and the biological lithogenesis is very intensity. Our workaround that the stratum of late carboniferous is including kinds of mud mound,and it is the ideally area to research the mud mound of late carboniferour of south China.This text did biological and stratigraphical research on the stratum which develops reefs, analyzing the character of Fusulinida, Brachiopoda and coral particularly. By researching and contrasting confirm that the horizon producing reefs belongs to the upper carboniferous and namely the underpart of maping formation.Reefs of late carboniferous all develop at the margin of carbonate platform,under the infection of frequency changing environment,different kinds of reefs are replaced by reef-building community and form other reefs. Under different environment of the margin of platform,kinds of reef-building biology build different reefs, In particular,the mud mound is special.Cyanobacteria that in the stratum of late carboniferous southern Guizhou province is another kind of important agglomerating biology:cyanobacteria, it effects through three manners:binding action, binding covering action and wrapping action. It forms different sizes of mud mound. There are a lot of filamentous from algae in the mud mound.It is the remains of the cyanobacteriaThe distribution of mud mound in southern Guizhou provience is more extensive,especially in the place of lumazhai. According to the scale of its development, the author will divide mud mound into three types, namely:large mud mound, mud mound of medium, small mud mound. The following features: 1. Fabric features:The characteristics of appearance is quaquversal.The core of mud mound is made up by mud calcareous rock,which contain the filament of algal, and occasionally there are some mass.There are no clear difference between the core of mud mound and the tip of mud mound.The both sides of mud mound is made up by bio-clastic limestone. From outocrop and under the microscope are visible crystal holes,which is filled by calcite.2.Rock compositionThe composition of mud mound is mud limestone and little clot rock.However, bones particles is less, mud is more,which indicating that for the deeper water, the hydrodynamic conditions of the depositional environment is thin.3.Fossils and ancient ecological:in the same stratum,there is rich in a variety of sedimentary biological, brachiopods, triticites, foraminiferal, crinoids, bryozoans and corals, in sharp contrast with this is that the mud mound is low abundance and species monotonous. Occasional we can find single coral fossils, a small amount of flakes in crinoids, foraminifera, as well as types of triticites fossil.The mud mounds were pressed from both sides gray to gray-black limestone.though the deep observation and studying, The author divide mound building process into three types,namely:the building of fundus、the building of core、the building of tip.There are a lot of factors which can affect the building of mud mounds:1. Rate of transgressionThe study also found that:when the rates of transgression and mud mound growth rate at a similar conditions, the mud mound can grow better. When water depth in a smaller conditions, the transgression rate is slightly larger than the growth rate of mud mound, the mud mound has large growth space to vertical grow,then to build the core of mud mound; when transgression rate is less than the growth rate of mud mound, the mud mound change the growth from vertical aggradation to lateral growth.In depth water circumstances, when the transgression rate less than or equal to the growth rate of mud mound,it is beneficial to bacteria, algae and other micro-organisms breeding;when the rate of transgression is larger than the growth rate of mud mound, it is not conducive to bacteria, algae and other microbial reproduction. Mud mounds’growth hare restricted, when the sea-level fluctuations is adapt to the bacteria, algae micro-organisms breeding, they began to building the core.2. The effects of water depth and sunlightWere found in the study, mud mounds hare no significant barrier deposition,there are no significant difference between the two sides, and small particles, mainly be made up by limestone and mud limestone, bone particles and other small particles are less.It proves that the hydrodynamic conditions of mud mound living in the work area is weak. There are little biomass in the mud mound which is single.It prove that the depth of water which is suit for mud mound growing is not suit for other biological who need more illumination and a large amount of nutrients.Namely:the environment of mud mound growing is the weak hydrodynamic transmission and transmittance of sedimentary environment.When the water depth, hydrodynamic conditions is suit for the growing of microorganisms, they begin to reproduct large population, and secret slime to bond the calcium in water and bioclastic.flowing the sea levels rising, the hydrodynamic conditions get strengthening, the building of mud mounds is impeded,the mud mound construction gets slow.when the sea levels rising again,the growth of mud mound will end.3. The impact of water temperatureMany scholars believe that mud mounds are made by microorganisms, also we find that it can make carbonate precipitation in modern lakes. The mud mounds’building is considered that it is the beginning of biofilm to trigger precipitation of calcium carbonate. Cyanobacteria which has been found in work area often live in warm environment.When the temperature falls, microorganisms metabolize slowlyand the rate of building mud mound gets slow. When the temperature falls to someone, microorganisms stops building the mud mound.The rising of mound get stoping.So water temperature is one of the important factors which can control the growth of mud mound.To sum up, the building of mud mound subjects to many factors, only suit to their growth and development environment, their growth and development can be flourish. Namely:The survival of the fittest.Through the comparative study with Waulsortian, founding that the mud mounds which develop in southern Guizhou provience are more difference with Waulsortian, so as to identify that the mud mounds are not Waulsortian like.

中国黔南晚石炭世生物灰泥丘生长发育特征研究

摘要5-8Abstract8-11目录12-14前言14-18第一章 生物灰泥丘研究概况18-24    1.1 世界泥丘的研究历史及现状18-19    1.2 中国泥丘研究概况及评述19-20    1.3 存在问题和研究晚石炭世生物泥丘意义20-24第二章 黔南晚石炭世区域地质特征24-28    2.1 自然地理概况24    2.2 黔南晚石炭世大地构造背景24-25    2.3 研究区地层及古生物概况25-26    2.4 黔南晚石炭世沉积类型26-28第三章 黔南晚石炭世泥丘相地层生物地层学研究28-38    3.1 泥丘相剖面28-33        3.1.1 路马寨泥丘的横剖面29-30        3.1.2 路马寨泥丘的纵剖面30-31        3.1.3 路马寨泥丘剖面31-33    3.2 礁相地层生物群特征33-38        3.2.1 蜓类33-36        3.2.2 泥丘中的其他生物36-38第四章 黔南晚石炭世生物灰泥丘特征38-52    4.1 黔南生物灰泥丘分类38-42    4.2 成岩作用特征42-46    4.3 影响灰泥丘发育的因素46-47    4.4 灰泥丘的生长发育过程47-50    4.5 黔南地区生物灰泥丘总特点50-52第五章 黔南生物灰泥丘与世界Waulsortian丘对比研究52-64    5.1 Waulsortian丘概述52-56        5.1.1 Waulsortian相的结构53-55        5.1.2 密西西比Waulsortian丘实例55        5.1.3 Waulsortian丘总特点55-56    5.2 黔南生物灰泥丘与世界Waulortian丘对比56-64        5.2.1. 规模对比57-58        5.2.2. 岩相对比58-59        5.2.3. 造丘生物对比59        5.2.4. 丘内常见生物对比59        5.2.5. 成丘地层对比59-60        5.2.6. 晶洞充填及裂隙充填对比60-61        5.2.7. 丘体结构对比61        5.2.8. 成岩作用对比61-62        5.2.9. 沉积环境对比62-64第六章 主要结论64-66图版说明66-70图版70-78参考文献78-86致谢86

  本文关键词：黔南晚石炭世生物灰泥丘生长发育特征研究，由笔耕文化传播整理发布。