Ocean stagnation and ventilation defined by δ34S secular trends in pyrite and barite, Selwyn Basin, Yukon
Ocean stagnation and ventilation defined by δ34S secular trends in pyrite and barite, Selwyn Basin, Yukon
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DOI：
10.1130/0091-7613(1984)12
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发表时间：
1984-10
期刊：
影响因子：
5.8
通讯作者：
W. Goodfellow;I. Jonasson
中科院分区：
文献类型：
--
作者：
W. Goodfellow;I. Jonasson
在表层塞尔温盆地内，古生代至少可以识别出三个旋回，水体从开放、通风状态交替到封闭、分层状态。这些循环是通过黄铁矿中的 δ34S 值记录的，这些值在停滞期间超过了同时期海水的 δ34S 值，并在较大循环期间显着下降。分层海中形成的黄铁矿 δ34S 值的显着增加是由细菌还原为硫化物的硫酸盐的高百分比以及黄铁矿沉积过程中从封闭系统中去除同位素较轻的硫控制的。在此期间重晶石的 δ34S 曲线具有与平均蒸发岩曲线相似的形状，只是它发生正位移，特别是在弗拉斯尼期。弗拉斯尼亚时代重晶石 δ34S 值的显着增加与同位素较重的硫（较早在分层水柱中积累）与通风事件期间地表水的混合相一致。
Within the epicratonic Selwyn Basin, at least three cycles can be recognized for Paleozoic time when the water column alternated from open and ventilated to closed and stratified conditions. These cycles are recorded by δ34S values in pyrite that exceed those for coeval seawater during periods of stagnation and decrease markedly during periods of greater circulation. The marked increase in δ34S values for pyrite formed in stratified seas is controlled by the high percentage of sulfate bacterially reduced to sulfide, coupled with the removal of isotopically lighter sulfur from a closed system during pyrite sedimentation. The δ34S curve for barite during this time has a shape similar to the mean evaporite curve except that it is displaced positively, particularly in Frasnian time. This pronounced increase in δ34S values for barite of Frasnian age coincides with the mixing of isotopically heavier sulfur, accumulated earlier in a stratified water column, with surface waters during a ventilation event.