中国首次发现白垩纪桫椤科茎干化石

发布时间：2018-05-31 01:33

本文选题：桫椤科 + 树蕨　；参考：《地球学报》2017年02期

【摘要】：松辽盆地是我国白垩系分布最广、厚度最大、发育最全的陆相沉积盆地。孢粉分析发现桫椤孢在松辽盆地白垩系中比较常见。但由于桫椤孢与桫椤科或者蚌壳蕨科具有亲缘关系。桫椤孢在地层中的发现不能明确表明桫椤科植物的存在。这种状况影响了我们对松辽盆地古环境和古气候的精确分析。白垩纪桫椤科矿化茎干化石在黑龙江省齐齐哈尔市克山县的发现为解决桫椤科植物在松辽盆地存在与否的难题提供了重要证据。该化石为桫椤科树蕨植物的茎干片段,包括髓、网状中柱、皮层。分体中柱的横截面呈U、W或S形,外围具有厚壁组织鞘,分体中柱末端朝向髓部或者皮层。髓和皮层由薄壁组织组成,其中分布有许多维管束和根。创伤组织在髓中常见。当前化石是我国第一个桫椤科茎干化石记录。它的发现表明白垩纪时期松辽盆地北部曾经分布着现今多生长于热带、亚热带的桫椤科树蕨祖先类群。结合与其伴生的一些登普斯基树蕨、本内苏铁茎干等化石证据,可能指示当时气候为热带或者亚热带。
[Abstract]:Songliao Basin is the most widely distributed, thickest and most developed continental sedimentary basin in Cretaceous in China. Sporopollen analysis showed that Alsophila spinulosa is common in the Cretaceous system of Songliao Basin. However, Alsophila spinulosa is related to Alsophila or Crimopteris. The discovery of Alsophila spinulosa in the strata does not clearly indicate the existence of Alsophila. This situation affects our accurate analysis of paleoclimate and paleoclimate in Songliao Basin. The discovery of Cretaceous mineralized stem fossils of Alsophila in Keshan County, Qiqihar City, Heilongjiang Province, provides important evidence for solving the problem of the existence of Alsophila spinulosa plants in Songliao Basin. The fossil is the stem of the ferns of the family Alsophila, including the pulp, reticular column, and cortex. The cross section of the column in the split is UW or S shape, the outer part has thick wall tissue sheath, and the end of the column in the split is oriented towards the medullary part or cortex. The medulla and cortex are composed of parenchyma with many vascular bundles and roots. Traumatic tissue is common in the marrow. The present fossil is the first fossil record of the stem of Alsophila spinulosa in China. Its discovery indicates that the northern part of Songliao Basin during the Cretaceous period was dominated by tropical subtropical ferns of Alsophila spinulosa. Combined with the fossil evidence of some of the associated Dempkowski ferns and cycads, it may indicate that the climate was tropical or subtropical at that time.
【作者单位】：中国地质博物馆;
【基金】：国土资源部部门预算项目(编号:121113000000160034) 国家自然科学基金项目(编号:31170206)联合资助~~
【分类号】：Q914.2

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