2Kinetics_homo.pdf

Geochemical Kinetics! Part I.! Kinetics of homogeneous reactions Please Read ?! Zhang, 1994, EPSL, 122, 373-391 (reactions of reversible reactions during cooling) ?! Textbook: Pages 96-172 in Zhang, 2008 137 in !#$% ?! Papers to be discussed: April 25 and 27 Discussion topic 1 Fe-Mg order-disorder reaction in opx: kinetics and geospeedometry Besancon, 1981; Anovitz et al., 1982; ! Ganguly,1982; Saxena, 1983 Ganguly et al, 1994, 1996, 1999, 2000 Kroll et al., 1997, Eur J Mineral 9, 705! Stimpfl et al., 1999, CMP 136, 297! Wang et al., 2005, GCA 69, 5777! Discussion Leader: Youxue Zhang! Discussion topic 2 Hydrous species reaction: kinetics and geospeedometry Zhang et al. 1995, Am Mineral, 80, 593 Zhang et al. 1997, GCA, 61, 2167 Zhang et al. 2000, GCA, 64, 3347 (improvement) Xu and Zhang 2002, EPSL, 200, 315 Wallace et al. 2003, Bull Volcanol 65, 105 Discussion Leader: How to contribute to discussion ?! Read the distributed papers and understand them. Go through the derivations ?! If you have questions, ask during the discussion. We may not have enough time to go through every derivation step. Hence try to solve these before coming to the class ?! If you understand something well, summarize it ?! If you gain insights that the authors did not reveal, let the class know ?! If you think some aspect of the research can be improved, discuss it in the class ?! If you think that the authors made mistakes, raise these points ?! Anything else related to the papers that you want to point out Kinetics of homogeneous reactions, examples ?! Nuclear reaction: 87Rb ! 87Sr ?! Nuclear reaction: 41H ! 4He (in star cores) ?! Chemical reaction in gas: ! 2CO(gas) +O2(gas) ! 2CO2(gas) ?! Chemical reaction in water: ! H2O(aq) + CO2(aq) ! H2CO3(aq) ?! Chemical reaction in melt: ! H2O(melt) +O(melt) ! 2OH(melt) ! Q2(melt) + Q4(melt) ! 2Q3(melt) ?! Chemical reaction in orthopyroxene: ! Mg2+M1(opx)+Fe 2+ M2(opx) ! Fe 2+ M1(opx)+Mg 2+ M2(opx) Kinetics of homoge