Stress-induced chemical waves in sediment burial diagenesis
Stress-induced chemical waves in sediment burial diagenesis
复制标题
沉积物埋藏成岩作用中应力诱发的化学波
DOI：
10.1038/ncomms1684
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发表时间：
2012
影响因子：
16.6
通讯作者：
D. Budd
中科院分区：
文献类型：
--
作者：
Yifeng Wang;D. Budd
在许多白云岩地层中发现了孔隙度和成分的横向米级周期性变化。这种变化可能包含有关白云岩形成和转化的重要信息。在这里，我们表明，这些变化可能是在沉积物埋藏成岩作用过程中出现的应力介导的矿物-水相互作用的化学波。在上覆载荷作用下，孔隙度较高的晶畴中的晶体受到较高的有效应力，导致压溶。溶解的物质扩散到邻近的较低孔隙度区域并在其中沉淀，从而进一步降低孔隙度。这种正反馈导致了白云岩的侧向孔隙度和成分模式。图案几何形状取决于流体流动状态。在扩散主导的情况下，低孔隙度域和高孔隙度域在空间上交替，没有方向偏好，而在存在平流的情况下，这种交替仅沿着流动方向发生，像化学波一样传播。我们的工作为解释沉积岩中的成岩特征提供了一个新的视角。
Lateral metre-scale periodic variations in porosity and composition are found in many dolomite strata. Such variations may embed important information about dolomite formation and transformation. Here we show that these variations could be fossilized chemical waves emerging from stress-mediated mineral-water interaction during sediment burial diagenesis. Under the overlying loading, crystals in higher porosity domains are subjected to a higher effective stress, causing pressure solution. The dissolved species diffuse to and precipitate in neighbouring lower porosity domains, further reducing the porosity. This positive feedback leads to lateral porosity and compositional patterning in dolomite. The pattern geometry depends on fluid flow regimes. In a diffusion-dominated case, the low- and high-porosity domains alternate spatially with no directional preference, while, in the presence of an advective flow, this alternation occurs only along the flow direction, propagating like a chemical wave. Our work provides a new perspective for interpreting diagenetic signatures in sedimentary rocks.