The small Plio-Quaternary volcanic centre of Cabezo Negro de Tallante in SE Spain includes a thick deposit of polymictic pyroclastic tuff-breccia, whose fragments are agglutinated by a carbonate-rich component. This feature is also observed in other monogenetic volcanic centres cropping out in the Tallante-Cartagena volcanic district. The carbonate fraction has been recently interpreted in literature as representing a mantle component, therefore pointing to the existence of a diffuse carbonatitic activity in the area.

Based on detailed sedimentological (presence of pisoids and root remnants), petrographic (presence of plagioclase and absence of euhedral silicate minerals in the calcite plagues), mineral chemistry (Ba-Sr-poor calcite composition), whole-rock chemistry (overall low incompatible element content in the pure carbonate fraction and a monotonous trace element negative correlation with CaO) as well as isotopic constraints (perfect correlations between Sr-Nd-Pb isotopic ratios with CaO in the basaltic and carbonate fraction, as well as heavy δ¹⁸O and light δ¹³C isotopic composition of the carbonate fraction), we propose a secondary origin for the carbonate component, excluding any contribution of mantle carbonatite melts. The presence of carbonates infiltrating the abundant mantle and crustal xenolith fragments found in the pyroclastic breccia is not related to the presence of carbonatitic melts at mantle to lower crustal depths, but to in-situ fragmentation of the Strombolian tuff-breccia deposit, followed by secondary carbonate infiltration. The pyroclastic breccia was indeed affected by an alternation of carbonate precipitation and dissolution in a vadose zone, where the activity of bacteria, fungi, roots and meteoric water led to the formation of a calcrete (caliche)-type deposits.

Basaltic rocks (hawaiites and basanites) occur in the area as scoria and lava fragments in the pyroclastic breccia as well as small lava flows. They have been modelled with a low-degree partial melting of an amphibole-bearing peridotitic mantle close to the lithosphere-asthenosphere boundary. The origin of the mildly alkaline sodic basaltic activity in SE Spain post-dates the abundant and long-lasting subduction-related volcanic phase in the Betic Chain. Its origin is explained without requiring the presence of any thermal anomaly, but simply as consequence of the difference of lithospheric depths and edge-driven-type small-scale convection.

西班牙东南部Cabezo Negro de Tallante的小第四纪第四纪火山中心包括厚厚的多发性火山碎屑角砾岩沉积物，其碎片被富含碳酸盐的组分凝集。在塔兰特-卡塔赫纳火山区的其他单相火山中心也观察到了这一特征。碳酸盐馏分最近在文献中被解释为代表地幔组分，因此指出该地区存在弥散的碳酸盐活动。

基于详细的沉积学（类胡萝卜素和根残留物），岩石学（方解石鼠疫中存在斜长石和不含正硅酸盐矿物），矿物化学（方解石中钡锶锶含量低），全岩石化学（总体上为低相容性）在纯碳酸盐馏分并与CaO的单调微量元素负相关元件的内容）以及同位素约束（在玄武和碳酸盐分数锶的Nd-Pb同位素比率与CaO的之间完美的相关性，以及重质δ ¹⁸ O和光δ ¹³碳酸盐馏分的C同位素组成），我们提出了碳酸盐组分的次要成因，但不包括地幔碳酸盐熔体的任何贡献。碳酸盐岩渗透到火山碎屑角砾岩中发现的大量地幔和地壳异岩碎屑中，与地幔中较低地壳深度的碳酸盐岩熔体的存在无关，而是与斯特伦伯利亚凝灰岩角砾岩沉积物的原位破碎，然后是次生的碳酸盐渗透。火山碎屑角砾岩确实受到碳酸盐沉淀和溶质在渗流带中交替变化的影响，在渗流带中，细菌，真菌，根和流水的活动导致钙质（钙镁矿）型沉积物的形成。

玄武岩（夏威夷岩和玄武岩）以火山碎屑角砾岩中的火山灰和熔岩碎片以及少量熔岩流出现在该区域。它们是通过岩石圈-软流圈边界附近的含闪石的橄榄岩地幔的低度局部熔融来模拟的。西班牙东南部温和碱性苏打玄武岩活动的起源可以追溯到比蒂克链中与俯冲有关的丰富而持久的火山相。解释其起源时无需存在任何热异常，而仅是岩石圈深度和边缘驱动型小尺度对流差异的结果。