中生代主要植物化石的古气候指示意义

中生代植物群以真蕨纲、苏铁纲、银杏纲、松柏纲为主,另有苔藓类、石松纲、楔叶纲及其他种子植物等。从化石的形态和结构、埋藏特点、分布及与现生类型的对比等方面，概要地分析了中生代植物群常见分子的古气候指示意义。其中,反映温暖潮湿气候或生境的主要有苔藓类,石松纲的Lycopodites和Selaginellites属等,楔叶纲,真蕨纲的单缝孢类、早白垩世的蚌壳蕨科、海金砂科的Ruffordia属、紫萁科及可能相关的小羽片大型的Cladophlebis,银杏纲银杏目的主要类型,松柏纲杉科的Athrotaxoites、Cunninghamia、Cephalotaxopsis、Sequoia等,紫杉科的Taxus、Torreya等，苏铁杉科Ferganiella、Podozamites、Swedenborgia等以及形态属Elatocladus；反映温凉气候的主要有松柏纲的松科和银杏纲的茨康目；适应热带、亚热带气候的包括真蕨类的海金沙科、合囊蕨科、马通蕨科、双扇蕨科、桫椤科、里白科以及中国蕨科的Onychiopsis等,苏铁目和本内苏铁目的主要类型；指示偏干旱型气候的主要有石松纲的Pleuromeia和Isoetites, 真蕨纲的Weichiselia, 本内苏铁目的Otozamites、Zamites、Ptilophyllum等,松柏纲掌鳞杉科的Pseudoflenelopsis、Flenelopsis、 Hirmeriella和可能属于掌鳞杉科的Brachyphyllum和Pagiophyllum,柏科的Cupressinocladus以及买麻藤目的Ephedrites等。

Palaeoclimatic implications of the main Mesozoic fossil plants of the Mesozoic

The typical Mesozoic floras are mainly composed of Filicopsida, Cycadopsida, Ginkgopsida and Coniferopsida, as well as some Bryophyta, Lycopdopsida, Sphenopsida and other seed plants. The palaeoclimatic implications of main fossil plants of the Mesozoic except the angiosperms are dealt with in this paper based on their morphologic and anatomic features, taphonomic data, geographic distribution and comparisons with their living affinitive groups. The Mesozoic plants with palaeoclimatic significances are roughly divided into four groups. The first one, which represents temperate-humid climate, consists of bryophytes; Lycopodites and Selaginellites of lycopods; sphenophytes; ferns including the Early Cretaceous Dicksoniaceae, Ruffordia of Schizaeaceae, Osmundaceae and Cladophlebis with large pinnules, monolete spore ferns, the main elements of the Ginkgoales; conifers including Athrotaxoites, Cunninghamia, Elatocladus, Swedenborgia, Cephalotaxopsis, Sequoia, Taxus, Torreya, Ferganiella, Podozamites, and etc..The second group mainly includes the Pinaceae of conifers and some of Ginkgopsida, especially the Czekanowskiales, which usually indicate a moderate-cool climate. The third group indicates warm tropical and subtropical climate, which mainly consists of ferns, such as Schizaeaceae, Marratiaceae, Matoniaceae, Dipteridaceae, Cyatheaceae, Gleicheniaceae and the possible sinopteridaceous fern Onychiopsis and most of the Cycadales and Bennettitales. The fourth group adapted to warm-arid climate is represented chiefly by the lycopod Pleuromeia and Isoetites; fern Weichselia; Bennettitales, such as Otozamites, Zamites, Ptilophyllum, Tyrmia, and etc.; the Cheirolepidaceae including Pseudoflenelopsis, Flenelopsis, Hirmeriella and the possible cheirolepidaceous conifers Brachyphyllum and Pagiophyllum; cupressaceous conifer Cupressinocladus; as well as the possible desert plant Ephedrites.