Influence of pore water chemistry on silica diagenesis: evidence from the interaction of diagenetic reaction zones with polygonal fault systems
Influence of pore water chemistry on silica diagenesis: evidence from the interaction of diagenetic reaction zones with polygonal fault systems
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孔隙水化学对二氧化硅成岩作用的影响：成岩反应带与多边形断层系统相互作用的证据
DOI：
10.1144/0016-76492009-049
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发表时间：
2010
影响因子：
2.7
通讯作者：
Ireland M
中科院分区：
文献类型：
--
作者：
Ireland M
来自东北大西洋边缘的三维地震资料显示，在渐新世地层中赋存的蛋白石-A-蛋白石-CT反应带是横切地层反射的明亮反射事件。在一些地区，反应带顶部的地形起伏具有显著的几何形状，包括大致圆形的平坦区域，相距1-3公里，由陡峭的凹槽或山脊组成的网络分隔，起伏可达200米。这里我们表明，这些地形结构形成于多边形断层的上端周围，残留物存在于蛋白石-A到蛋白石-CT横切反射以下的更深层次的地层中。此外，我们还推断，通过多边形断层瞬时排出的地层水的化学作用在它们的形成中一定起到了关键作用。在含硅系列中，蛋白石-A转变为蛋白石-CT，之后是更深层次的蛋白石-CT向石英的转变。蛋白石-CT到石英的转变释放镁，众所周知，镁可以在较低温度下促进蛋白石-A到蛋白石-CT的转变。因此，我们认为，当蛋白石-A-蛋白石-CT反应带接近多边形断裂系统的顶部时，它在被富含镁的孔隙水冲刷的地层中推进得更快。
Three-dimensional seismic data from the NE Atlantic margin have revealed opal-A to opal-CT reaction zones hosted in Oligo-Pliocene strata as bright reflection events that cross-cut stratigraphic reflections. In some areas, the topographic relief at the top of the reaction zone has a remarkable geometry comprising roughly circular flattish regions, spaced 1–3 km apart, separated by networks of steep-sided troughs or ridges with a relief of up to 200 m. Here we show that these topographic structures formed around the upper tips of polygonal faults, and that remnants exist at deeper stratigraphic levels below the opal-A to opal-CT cross-cutting reflection. Furthermore, we deduce that the chemistry of formation water expelled transiently through the polygonal faults must have played a key role in their formation. Within silica-bearing successions, the transformation of opal-A to opal-CT is followed by the transformation of opal-CT to quartz at greater depth. The opal-CT to quartz transformation releases magnesium, which is known to promote opal-A to opal-CT transformation at lower temperatures. Consequently, we suggest that when the opal-A to opal-CT reaction zone nears the top of the polygonal fault system, it advances more rapidly through strata flushed by pore water that is richer in magnesium.
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DOI：
--
发表时间：
2000
期刊：
Geological Society Special Publication
影响因子：
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作者：
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通讯作者：
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影响因子：
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作者：
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P. Holler
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影响因子：
3.5
作者：
J. Hein;D. Scholl;J. Barron;Marjorie G. Jones;Jacquelyn Miller
通讯作者：
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影响因子：
3.2
作者：
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通讯作者：
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