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鄂西利川晚二叠世长兴期碳酸盐台地的东缘与东南部,发育有台缘堤礁和缓坡丘状礁。在两类礁及相邻层段中,微量元素锶的分布有明显的规律性。堤礁的锶含量变化规律是:盆地相(平均1100ppm)>盆地边缘相(平均600ppm)>泻湖相(平均315ppm)>前礁斜坡相(平均161ppm)>礁核相(平均117ppm)。丘状礁的锶含量(平均458—531ppm)远大于堤礁的锶含量,且由礁核经礁翼到泻湖相锶含量渐增。锶的这一分布特征反映了不同类型的礁和同一礁的不同相段所经历的沉积和早期成岩环境不同。堤礁礁核形成于强水动力条件下,早期成岩作用处于相对开放的系统中,原生沉积物中的锶被充分淘汰,形成低锶段,而丘状礁和盆地相沉积物形成于弱水动力条件下,早期成岩作用处于相对封闭系统之中,因而锶的剩佘含量也偏高。
Late Permian Permian Changxing period carbonate platform in the eastern and southeastern part of western Hubei, developed a platform edge reefs and gentle slope reefs. In two types of reefs and adjacent layers, the distribution of trace elements strontium has obvious regularity. The variation of strontium content in the dike reefs is: basin facies (average 1100ppm)> basin margin (600ppm average)> lagoon facies (315ppm average)> forerock slope facies (161ppm average)> reef nuclear phase (117ppm average). Strontium reef strontium content (average 458-531ppm) is much larger than the strontium reef strontium content, and by reefs to the lagoon strontium content increased. This distribution of strontium reflects the different depositional and early diagenetic environments experienced by different types of reefs and different phases of the same reef. The dike reef reef core formed under strong hydrodynamic conditions, the early diagenesis was in a relatively open system, the strontium in the primary sediment was fully eliminated to form a low strontium segment, while the fossil reef and basin sediments formed in the weak water Under dynamic conditions, the early diagenesis is in a relatively closed system, so the residual content of strontium is also high.