【摘要】 地表钙华,是喀斯特地区普遍存在的一种沉积体,是陆相碳酸钙沉积的重要类型。长期以来陆相碳酸钙沉积的水动力成因观点为大多数人所熟悉(1)(2),生物成因观点则研究较少,在实际中生物作用过程也是不可忽略的,特别是藻类的沉积作用。论文以几种典型的蓝藻为例,通过对自然界水动力条件的模拟,对蓝藻藻类进行了几种水动力条件下的碳酸钙生物沉积试验研究,对比研究了在不同水动力条件下,蓝藻钙化沉积过程。试验得出了钙藻生长与钙化沉积的最适宜水动力为0～60 rpm,在过强的水动力条件下,蓝藻的生长将受到抑制,从而降低蓝藻的钙化沉积速率。文章讨论了在瀑布条件下的陆相碳酸钙沉积是以水动力成因为主导,而在水动力条件较弱的河流中以生物成因为主导,从而提出了,陆相碳酸钙沉积的水动力—生物双成因观点。文章还探讨了在静止状态下,藻类沉积对碳酸钙沉积的贡献大小,叠层石所指示的安静的沉积环境。更多还原

【Abstract】 The surface calcification is a kind of deposit on the earth,which is an important deposit type of land calcium carbonate.For a long time,the hydrodynamic formation cause of land calcium carbonate deposit is familiar to the researchers.The research of the biological cause of the formation is relatively fewer.In fact,the biological cause should be not ignored as well,especially algous deposit process.From imitating for field hydrodynamic force condition,taking the blue-green algae for example,the research makes a biological deposit test under the different hydrodynamic force condition.From the test,we get optimum hydrodynamic condition of algae growth and their calcification rate,that is under the rate of 0~60 rpm,under the excessive strong,the growth of blue-green algae will be restrained,and reduce the deposit rate of calcium carbonate.Under the condition of waterfall,hydrodynamic force is strong,in calcium carbonate depositing process,hydrodynamic formation cause of land calcium carbonate deposit is the lead cause;Under the weaker hydrodynamic condition,such as in river bed,biological calcification deposit will be the lead cause.Therefore,hydrodynamic-biological cause viewpoint has been proposed in the article.From the field algous samples,the calcium carbonate depositing test has been done under the different water hydrodynamic conditions.The test results show that under the faster water condition,most calcium carbonate will deposit very quick,and fewer algae calcium carbonate will precipitate because of adverse living environment under the condition.And under the slower water condition,because of being avail for algae’s living,more algae calcium carbonate will precipitate,and few calcium carbonate will deposit under the condition without algae.Also,under the motionless condition,contribution of calcium carbonate deposit have been compared in the article between the algous environment and without algous environment.The article presents,while without algous,under the motionless condition,the calcium carbonate depositing is controlled by liquid equilibrium state,over saturation liquor will keep the deposition going,unless the liquor is saturated.But,while algous join,under the motionless condition,the calcium carbonate depositing may not be controlled by liquid equilibrium state,algous calcium carbonate deposit will keep going,even if it is saturated.So,under the faster flow condition,without doubt,fast flow makes CO2 in liquor overflow,calcium carbonate will deposit in quantity,while the contribute from algous calcium carbonate deposit is few.Under the motionless condition,Mechanism of CO2 overflowing almost disappear,or weak,corresponding calcium carbonate deposit is few,and algous calcium carbonate deposit is main.Then,in nature,largely stromatolite may indicate a quiet deposit environment.更多还原