A skeletal assemblage classification system for non-tropical carbonate deposits based on New Zealand Cenozoic limestones
A skeletal assemblage classification system for non-tropical carbonate deposits based on New Zealand Cenozoic limestones
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DOI：
10.1016/0037-0738(95)00071-2
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发表时间：
1995-12-01
影响因子：
2.8
通讯作者：
Hood, SD
中科院分区：
文献类型：
--
作者：
Hayton, S;Nelson, CS;Hood, SD
新西兰新生代石灰岩主要是在非热带气候条件下，在开阔的海陆架或斜坡环境下形成的骨架灰岩和包岩。在对近500个石灰岩样品中的骨骼组分的性质和丰度进行岩石学分析后，完整的连锁聚类分析确定了7个主要的骨骼组合，它们可能是Lees和Buller(1972)为温带地区碳酸盐沉积定义的单一有孔虫骨骼组合的亚类。这7个组合的缩写名称如下：(A)Barnamol=藤壶/双壳类为主；(B)Bimol=双壳类为主；(C)苔藓类=苔藓类/双壳类为主；(D)棘皮类=棘皮类/底栖有孔虫为主；(E)Nannofor=超微化石/浮游有孔虫为主；(F)红藻=钙质红藻为主；(G)Rhdechfor=钙质红藻/棘皮动物/底栖有孔虫为主。根据未知样品的三种主要骨架成分，设计了一种用于命名未知样品骨架组合的复合三角分类图。该图解成功地刻画了超过85%的新西兰新生代石灰岩样品，似乎也适用于许多海外非热带碳酸盐矿床的骨架组合指定。限制主要涉及当地常见的骨骼类型(例如锯齿类、腕足类)，这些类型目前没有纳入新西兰的方案。七个骨骼组合中每一个的主要骨骼贡献者的一般生态偏好构成了将这些组合与广阔的陆架生境联系起来的基础。因此，除了为不同工作者之间的比较研究提供更一致的骨骼组合术语的好处之外，该方案还可以帮助进行非热带骨骼碳酸盐相的古环境解释。
Cenozoic limestones in New Zealand are mainly skeletal grainstones and packstones formed under non-tropical climatic conditions in open marine shelf or ramp environments. Following petrographic analysis of the nature and abundance of the skeletal components in nearly 500 samples of these limestones, a complete linkage cluster analysis identified seven major skeletal assemblages that may be regarded as subdivisions of the single foramol skeletal association defined by Lees and Buller (1972) for temperate-region carbonate deposits. The seven assemblages are given contracted names, as follows: (a) barnamol = barnacle/bivalve-dominated; (b) bimol = bivalve-dominated; (c) bryomol = bryozoan/bivalve-dominated; (d) echinofor = echinoderm/benthic foraminiferal-dominated; (e) nannofor = nannofossil/planktonic foraminiferal-dominated; (f) rhodalgal = calcareous red algal-dominated; and (g) rhodechfor = calcareous red algal/echinoderm/benthic foraminiferal-dominated. A composite triangular classification diagram has been devised for naming the skeletal assemblage of an unknown sample on the basis of its three main skeletal components. The diagram successfully characterises more than 85% of the New Zealand Cenozoic limestone samples and also appears to be applicable for the skeletal assemblage designation of many overseas examples of non-tropical carbonate deposits. Limitations relate mainly to locally common skeletal types (e.g. serpulids, brachiopods) that are presently not incorporated into the New Zealand-based scheme. The general ecological preferences of the main skeletal contributors in each of the seven skeletal assemblages form a basis for relating the assemblages to broad shelf habitats. Consequently, as well as the benefits of providing a more consistent skeletal assemblage terminology for comparative studies between different workers, the scheme can assist with the paleoenvironmental interpretation of non-tropical skeletal carbonate facies.