Determination Of The Content Of Black Carbon From Black Rock Series And Geological Significance In Songlin, Zunyi

Black carbon is usually considered the remnant coming from incomplete burning of fossil fuel or biology organism and has two kinds of source, one is local sourse: the carbon particle by biology direct combustion;The other is ecdemic: the micron and hypo-micron class particle that result from the burning of fossil fuel such as coal and petroleum during industry activity and traffic transport float in the air, then drop and sediment into soil after long-distance transfer. The sedimented carbon particle settle again by the action of mechanical transit such as water erodibility and wind raises. In the early Cambrian of Zunyi area, the content of balck carbon is more abundant in the extensive black rock series. We conjecture the black carbon may be source of the incomplete combustion of firedamp gas during volcano activity and then get together to drop and sediment by atmosphere and water in the early Cambrian black rock series, Zunyi according to the condition of anoxic atmosphere, unicellular fungoid, algae biology, no grass and forest.Standing on the supposition, we begin experiment about determining the content of black carbon of rock samples in black rock series. According as the method of determining black carbon form soil and sediment, we take the example for standard samples and igneous clay rock in black rock series and experiment, and analyse corresponding error in order to check up the reliability of experiment method. We make dusty gabbro and standard microlite graphite into sample by different proportion and measure the content in order to prove the reliability of experiment method, as a result the reliability is fine. Because the error is main source of loss of oxidation, we make experiment to determine the rate of loss of extra oxidation. The result means the loss ratio of oxidation differs with each other after the extra oxidation for different kind of examples. We determine the content of black carbon of rock sample in black rock series by chemistry analysis. After one-off ration procedure and experiment step by step, the gross relative deviation reduces to 3.77% for the whole experiment procedures, of which 1.99% accounts for HF/HCl single treatment and 3.11% for K₂Cr₂O₇ oxidation. So the experiment means the analysis way is feasible.After confirming the reliability of experiment, we choose two typical black rock series sections of jianfengding and xiaozhuliushui near zhongnan village in Songlin area, Zunyi, and ascertain the abnormity of the content of black carbon down the sections by the way of experiment, and discuss the origin of black carbon according to the abnormity in order to open out the relation between black carbon and volcano activity in the early Cambrian.The data of experiment tell that the content of black catbon indicates two large-scale volcano activity in the early Cambrian companied by three abnormity spots. I-alkalescence volcano activity, II-carbonate volcano activity of seabed. Along the combinatorial section of phosphorite—volcano lava^K-bentonite--argillite including tuberculose phosphate rock under niutitang group of jianfengding, the two abnormity spots of the content of black carbon indicate two different period volcano action of the first volcano activity(K-bentonite ZNRP3-8, the average content of black carbon is 6.8150% and ZNRP3-1, 10.3249%). The content of black carbon increases gradually from the bottom to the top along the section of xiaozhuliushui, and appears the abnormity spots (9.9270%) in the rock-coal layer. It indicatethe secondly volcano activity.We come to conclusion we can reappear to the history of volcano activity in the earlyCambrian because the contentof black carbon is able to be the indication of volcano activity inthe Low-Cambrian because of it's more complete record in the samples of black rock seriesdown the section.