A cyclicity in the early brigantian (D2) limestones east of the clwydian range, north wales and its use in correlation
A cyclicity in the early brigantian (D2) limestones east of the clwydian range, north wales and its use in correlation
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DOI：
10.1002/gj.3350140105
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发表时间：
2007-04
影响因子：
1.8
通讯作者：
I. Somerville
中科院分区：
文献类型：
--
作者：
I. Somerville
对于第一次，轻微的周期性被描述为从一些石灰岩在下半部分的Brigantian（D2）继承的模具区北威尔士，可以追溯到整个地区，使详细的相关性建立。小的周期性可能是由海平面升降引起的。与每个海退阶段相关联的出现时期由陆上特征和陆地沉积物的存在来证明。通过与已建立的动物群和岩性层位进行比较，证实了这些周期的横向持久性。简要讨论了与约克郡、德比郡和布里斯托其他旋回布里冈阶地层的对比。描述了北威尔士的Asbian/Brigantian（D1/D2）边界，并记录了与英格兰北部层型区相似的独特的动物群和岩性变化。
For the first time, minor cyclicity is described from some limestones in the lower part of the Brigantian (D2) succession of the Mold district North Wales which can be traced throughout the area enabling a detailed correlation to be established. The minor cyclicity may have been caused by eustatic sea-level fluctuations. Periods of emergence associated with each regressive phase are demonstrated by the presence of subaerial features and terrestrial deposits. The lateral persistence of the cycles is confirmed by comparison with established faunal and lithological horizons. Correlation with other cyclic Brigantian strata in Yorkshire, Derbyshire and Bristol is briefly discussed. The Asbian/Brigantian (D1/D2) boundary in North Wales is described and distinctive faunal and lithological changes similar to those in the area of the stratotype in north England have been recorded.