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1、Arsenic in the hydrothermal fluids :Why?Arsenic: environmental toxinore-forming elementrarely investigated 第1页/共13页第一页，共14页。 The amount of As in different settings the amount of As in different settings(g L-1)emerging settingopen ocean seawaterMOR BAB settingsIA shallow-water settingsthe amount of A
2、saround 1.72480.513865850第2页/共13页第二页，共14页。Factors controlling the amount of AsA.TemperatureB.PressureC.PHD.As mobility and speciationE.reaction time and maturity of the systemF.diverse chemical reactionsG.第3页/共13页第三页，共14页。第4页/共13页第四页，共14页。The relationship between the distribution of hydrothermal ven
3、ts and the depthHydrothermal vents are distributed in the range of hundreds of meters to 5000 mThe hydrothermal vents in the mid-ocean ridge area are distributed in the water depth of 2000-3000m第5页/共13页第五页，共14页。Phase separationResults:A.Produce a high Cl “brine” phase and a low Cl “vapor” phaseB.Ele
4、ments are fractionated between the brine and vapor phases C.As tend to enter into the vapor phase，it is due to the domination of the uncharged arsenite species at the prevailing pH and redox conditions, addition to Sulfur cyanide (HS) complexation. 第6页/共13页第六页，共14页。Additional input of As A.The syste
5、m offshore in Montserrat: enrichment of As here may be caused by enhanced magmatic input (in the form of magmatic volatiles) during the eruptive cycle. B.Sediment-fluid interaction: an additional cause for As enrichment could be leaching from As-rich sediments, prior to discharge.(no evidence)第7页/共1
6、3页第七页，共14页。Concentration of As in different marine rocks and sedimentsThe difference in As concentration between andesites and dacites (0.5-5.8)from the IA systems and the MORBs (1.0)is slight第8页/共13页第八页，共14页。ConclusionsA.Hydrothermal fluids from shallow-water island-arc (IA) settings are mostly ver
7、y high in As ，followed by fluids from deep-water hydrothermal systems in back-arc basins (BAB) ，and As concentration of mid-oceanic ridges (MOR) is comparably much lower .B.The only slightly higher bulk rock concentration of underlying acidic dacites and andesites from IA systems cannot be responsib
8、le for the overall much higher values of As compared to deep-water systems underlain by MORB. C.Phase separation produces a high Cl “brine” phase and a low Cl “vapor” phase. It is one of the most important factors controlling the concentration of As.D.Additional input of As due to magmatic volatiles
9、 and sediment-fluid interaction has to be considered. 第9页/共13页第九页，共14页。FollowingplanA.Conversion process of arsenate (AsV) and arsenite (AsIII) in submarine hydrothermal fluidB.The influence of pH and biological effects on the change of the valence state of arsenic第10页/共13页第十页，共14页。Reference1 Christ
10、ian Breuer , Thomas Pichler . Arsenic in marine hydrothermal fluids. Chemical Geology 348 (2013) 214.2马力. 基于地球化学模型对低温(dwn)热液中Au、As赋存状态的研究D.中国地质大学(北京),2017.3杨振林,丘宝国.砷元素与砷污染J.化学教学,1999(06):27-28.4陈雪刚,邱中炎,段威,李小虎,叶瑛,陈镇东.中国台湾龟山岛热液自然硫中微观包体的元素富集特征J/OL.地球科学:1-162018-10-16. 第11页/共13页第十一页，共14页。Thankyou!第12页/共13页第十二页，共14页。感谢您的观赏(gunshng)！第13页/共13页第十三页，共14页。内容(nirng)总结Arsenic in the hydrothermal fluids :Why。2马力. 基于地球化学模型对低温热液中Au、As赋存状态的研究D.中国地质大学(北京),2017.。3杨振林,丘宝国.砷元素与砷污染J.化学教学(jio xu),1999(06):27-28.。感谢您的观赏第十四页，共14页。
