A late Stephanian forest swamp with Sporangiostrobus fossilized by volcanic ash fall in the Puertollano Basin, central Spain
A late Stephanian forest swamp with Sporangiostrobus fossilized by volcanic ash fall in the Puertollano Basin, central Spain
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DOI：
10.1016/0166-5162(89)90064-5
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发表时间：
1989-06
影响因子：
5.6
通讯作者：
R. Wagner
中科院分区：
文献类型：
--
作者：
R. Wagner
卡斯蒂利亚-拉曼查普尔托拉诺盆地约600 m的煤系和油页岩含有晚期斯蒂芬尼亚植物群。一个火山灰瀑布，现在是一个夹在煤层III下部的凝灰岩带，使一个沼泽森林的地面变得肥沃，其中有丰富的成熟孢子囊叶松遗迹，这些遗迹与植物Bodeodendron（同一种石松植物）、pecopterid fern Scolecopteris和sphenophytesAsterophyllites和Annularia sphenophylloides有关。本文分析了这条凝灰岩带的植物区系组成，并确定了Sporangiostrobus断节过程的各个阶段。这些石松树的肥沃的顶端落在森林地面上，由于宽皮层区和管中柱的中心部分的腐烂，在那里发生了扁平化。随后，孢子叶的长的远侧层被去除，然后，孢子囊，只留下短的，水平的近侧部分的孢子叶附着在这些可育的茎尖或主要分支的船体。断节是这种异孢性石松植物的孢子囊传播的手段，产生Cristatisporites-Densosporites-Cingulizonatessmicrospores和Zonalesporites smegaspores. Sporangiostrobus是一个非常多产的致密孢子的生产者，并且Sporangiostrobus和煤层III的高致密孢子计数和硬粒岩含量之间有直接关系。描述了与煤层III相关的地层序列。环境条件进行了讨论，在有关的许多（超过一千标本）大，几乎完整的遗骸ofSporangiostrobus发现在较低的凝灰岩带。当火山灰落下时，这些分离的肥沃的顶点躺在森林的地面上，并在它们从Bodeodendrontree脱落的地方就地保存下来。这意味着没有水流，尽管从整体湖泊环境来看，总的环境一定是潮湿的。值得注意的是，这是欧洲和北美（古赤道带）罕见的例子之一，其中石松植物在斯蒂芬尼时代晚期仍然是主要的泥炭形成元素。并对孢子囊球孢属的系统地位作了简要讨论。该石松属植物属于保守类群，广泛分布于世界各地。由于很少有丰富的孢子虫化石，其在晚石炭世泥炭形成环境中的重要作用至今尚未被认识。
About 600 m of coal measures and oil shales in the Puertollano Basin of Castilla - La Mancha contain late Stephanian floras. An ash fall, now a tuff band intercalated in the lower part of coal seam III, fossilized a swamp forest floor with abundant matureSporangiostrobusremains that are associated with vegetativeBodeodendron(the same lycophyte), the pecopterid fernScolecopterisand the sphenophytesAsterophyllitesandAnnularia sphenophylloides. The floral composition of this tuff band was analyzed and the various stages of the disarticulation process ofSporangiostrobuswere determined. The fertile apices of these lycophyte trees fell onto the forest floor where flattening occurred as the result of decay of the wide cortical area and the central part of the siphonostele. Subsequently, the long distal laminae of sporophylls were removed and, afterwards, the sporangia, leaving only the short stubby, horizontal proximal parts of the sporophylls attached to the hulk of these fertile apices of stems or major branches. Disarticulation was the means of dissemination of the sporangia of this heterosporous lycophyte that producedCristatisporites-Densosporites-Cingulizonatesmicrospores andZonalesporitesmegaspores.Sporangiostrobuswas an extremely prolific producer of densospores, and there is a direct correlation betweenSporangiostrobusand the high densospore count and durite content of seam III. The stratigraphic succession associated with seam III is described. Environmental conditions are discussed in relation to the numerous (well over a thousand specimens) large, almost complete remains ofSporangiostrobusfound in the lower tuff band. The detached fertile apices were lying on the forest floor when the volcanic ash fall took place and were preserved in-situ where they were shed from theBodeodendrontree. This implies an absence of water currents, although the general environment must have been humid in view of the overall lacustrine setting. It is noted that this is one of the rare examples in Europe and North America (palaeoequatorial belt) where lycophytes continued to be the dominant peat-forming element in late Stephanian time. The systematic position ofSporangiostrobusis briefly discussed. This lycophyte belonged to a conservative group that was widely distributed throughout the world. Its important role in latest Carboniferous peat-forming environments has not been realized until now because of the rarity of richly preservedSporangiostrobusremains.