The diagenesis of travertine and tufa is rarely considered an issue due to the common difficulty of distinguishing what is primary from secondary, as in most of cases these diagenetic changes occur very early. The main diagenetic features of travertine and tufa formed within a volcanic ravine in the north of Gran Canaria (Canary Islands, Spain) are cementation within pores and cavities, and of micropores (< 0.06 mm), micritization, aggrading neomorphism, aragonite-to-calcite transformation, and dissolution. One of the most striking features is cementation of micropores between fibrous crystals of shrubs, spherulites and crusts. Micropore cementation leads to a textural change of the primary aragonite and calcite fibres to a massive crystalline texture retaining the original fibres. Early cementation of micropores in fibrous textures can be significant in understanding their preservation in ancient shrubs and spherulites, such as those of Cretaceous Pre-salt reservoirs. These diagenetic changes are strongly controlled by their low porosity and permeability, whereas diagenesis occurred in a different way in the more porous and permeable textures. The diagenetic changes described here occurred very early in both tufa and travertine, being almost totally restricted to the period immediately after deposition.

中文翻译：

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来自火山环境的全新世石灰华和凝灰岩的早期成岩特征（西班牙大加那利岛 Azuaje）

钙华和凝灰岩的成岩作用很少被认为是一个问题，因为在大多数情况下，这些成岩变化发生的很早，因此很难区分什么是原生的和次生的。在大加那利岛（西班牙加那利群岛）北部火山沟内形成的石灰华和凝灰岩的主要成岩特征是孔洞内的胶结作用，以及微孔（<0.06 毫米）、微晶化、变质新形作用、文石到方解石转化和溶解。最显着的特征之一是灌木、球晶和地壳的纤维状晶体之间的微孔胶结。微孔胶结导致原始文石和方解石纤维的质地变化为保留原始纤维的块状结晶质地。纤维结构中微孔的早期胶结对于了解它们在古代灌木和球晶中的保存具有重要意义，例如白垩纪盐下储层。这些成岩变化受到其低孔隙度和渗透率的强烈控制，而在更多孔隙和渗透性的构造中，成岩作用以不同的方式发生。这里描述的成岩变化发生在石灰华和石灰华的早期，几乎完全限于沉积后的时期。