Evaporites through time: Tectonic, climatic and eustatic controls in marine and nonmarine deposits
Evaporites through time: Tectonic, climatic and eustatic controls in marine and nonmarine deposits
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DOI：
10.1016/j.earscirev.2009.11.004
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发表时间：
2010-02
影响因子：
12.1
通讯作者：
J. Warren
中科院分区：
文献类型：
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作者：
J. Warren
在整个地质时期，蒸发岩沉积物是由太阳能驱动的表面或近表面盐水的浓缩形成的。以岩盐（巨型岩盐）或硬石膏（巨型硫酸盐）矿床为主的大型、厚而广的矿床往往是海相碳酸盐矿床，并可能与大量钾盐（巨型钾盐）矿床有关。古代海洋蒸发岩沉积需要特定的气候、海平面或构造并置，这种情况在过去已经发生过多次，将来也会再次发生。古海相碳酸盐岩在规模、厚度、构造和水文方面通常与第四纪碳酸盐岩相比发育较差。当巨型蒸发岩在适当的干旱气候和水文环境中活跃时，大量的海水被吸入海平面下的碳酸盐洼地。这些系统是典型的海洋沃茨蒸发率最大的地区，因此集中在过去的纬度相当于今天的马纬度。但是，就像今天的非海相碳酸盐岩一样，海相碳酸盐岩的位置在适当的绝热干燥和大陆性的区域延伸到赤道带。已开采的硼酸盐、碳酸钠（苏打灰）和硫酸钠（盐饼）盐矿床，沿着含富锂卤水的碳酸盐沉积物，需要大陆-大气而非海洋水文。利用地理信息系统绘制的世界中生代和新元古代蒸发岩矿床图表明，第四纪蒸发岩矿床与世界上大部分中生代蒸发岩矿床的对应关系很差。它们只与过去相同规模的大陆水文学直接相关，因此，本文中使用它们来更好地了解创建富含盐饼、苏打灰、硼酸盐和锂盐的床所需的条件。这些沉积物往往是新近纪的，大多发生在超sealevel水文地理隔离（内陆）大陆山间和沙漠边缘设置，受到新近纪冰室气候的雨-雨间振荡。与古代海相碳酸盐岩相比，现今的海相海底沉积物往往是小型的海缘沉积物，其分布和范围受到当前冰室驱动的海平面上升和缺乏适当的水文隔离的海底构造凹陷的限制。在过去的40年里，第四纪陆相湖泊存款模式一直被用于解释古代海相蒸发岩盆地，而没有认识到这种类型的比较具有时间限制的性质。古代巨型蒸发岩矿床（台地和/或盆地范围的矿床）需要陆表海道（温室气候）和/或大陆-大陆接近的条件。在板块构造尺度上（威尔逊旋回中的晚期阶段E到阶段B），大陆-大陆的接近促进了全盆地蒸发岩沉积。这就产生了均衡反应，在适当的干旱气候带，大部分碰撞缝合带或初期张开的裂谷可能处于海平面以下，水文地理上是孤立的（海洋蒸发岩下降盆地），但仍通过持续的渗漏和偶尔的海洋溢流相结合而注入海水。盆地蒸发岩矿床按其形成的构造环境可分为：汇聚型（碰撞盆地）、发散型（裂谷盆地、前裂谷、同裂谷和后裂谷）和克拉通内型。古台地碳酸盐岩可以是盆地范围内沉积的一个子集，特别是在克拉通内凹陷盆地中，或者是广泛分布的陆表海台地充填的一部分。在后一种情况下，它们倾向于形成大型硫酸盐矿床，并与水文孤立的沉积物有关。
Throughout geological time, evaporite sediments form by solar-driven concentration of a surface or nearsurface brine. Large, thick and extensive deposits dominated by rock-salt (mega-halite) or anhydrite (mega-sulfate) deposits tend to be marine evaporites and can be associated with extensive deposits of potash salts (mega-potash). Ancient marine evaporite deposition required particular climatic, eustatic or tectonic juxtapositions that have occurred a number of times in the past and will so again in the future. Ancient marine evaporites typically have poorly developed Quaternary counterparts in scale, thickness, tectonics and hydrology. When mega-evaporite settings were active within appropriate arid climatic and hydrological settings then huge volumes of seawater were drawn into the subsealevel evaporitic depressions. These systems were typical of regions where the evaporation rates of ocean waters were at their maximum, and so were centred on the past latitudinal equivalents of today's horse latitudes. But, like today's nonmarine evaporites, the location of marine Phanerozoic evaporites in zones of appropriate adiabatic aridity and continentality extended well into the equatorial belts. Exploited deposits of borate, sodium carbonate (soda-ash) and sodium sulfate (salt-cake) salts, along with evaporitic sediments hosting lithium-rich brines require continental–meteoric not marine-fed hydrologies. Plots of the world's Phanerozoic and Neoproterozoic evaporite deposits, using a GIS base, shows that Quaternary evaporite deposits are poor counterparts to the greater part of the world's Phanerozoic evaporite deposits. They are only directly relevant to same-scale continental hydrologies of the past and, as such, are used in this paper to better understand what is needed to create beds rich in salt-cake, soda-ash, borate and lithium salts. These deposits tend be Neogene and mostly occur in suprasealevel hydrographically-isolated (endorheic) continental intermontane and desert margin settings that are subject to the pluvial–interpluvial oscillations of Neogene ice-house climates. When compared to ancient marine evaporites, today's marine-fed subsealevel deposits tend to be small sea-edge deposits, their distribution and extent is limited by the current ice-house driven eustasy and a lack of appropriate hydrographically isolated subsealevel tectonic depressions. For the past forty years, Quaternary continental lacustrine deposit models have been applied to the interpretation of ancient marine evaporite basins without recognition of the time-limited nature of this type of comparison. Ancient mega-evaporite deposits (platform and/or basinwide deposits) require conditions of epeiric seaways (greenhouse climate) and/or continent–continent proximity. Basinwide evaporite deposition is facilitated by continent–continent proximity at the plate tectonic scale (Late stage E through stage B in the Wilson cycle). This creates an isostatic response where, in the appropriate arid climate belt, large portions of the collision suture belt or the incipient opening rift can be subsealevel, hydrographically isolated (a marine evaporite drawdown basin) and yet fed seawater by a combination of ongoing seepage and occasional marine overflow. Basinwide evaporite deposits can be classified by their tectonic setting into: convergent (collision basin), divergent (rift basin; prerift, synrift and postrift) and intracratonic settings. Ancient platform evaporites can be a subset of basinwide deposits, especially in intracratonic sag basins, or part of a widespread epeiric marine platform fill. In the latter case they tend to form mega-sulfate deposits and are associated with hydrographically isolated …