The Mud Mound Developing Feature Of Late Carboniferousin In South Guizhou Province, China

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.