中文摘要：

报道藏北申扎永珠区德日昂玛一下拉剖面的永珠组孢子组合，发现孢子43属，70余种（包括未定种）。组合特征如下：1）缺乏欧美植物地理区早石炭世典型的石松类植物的小孢子Lycospora属及早石炭世晚期（维宪期）重要孢子属；2）出现较多早石炭世早期（杜内期），甚至泥盆纪晚期分子。呈现出新老化石的混合现象；3）北半球和南半球孢子的混合组合，同时也是冷、暖微古植物群混合，既有相当于中国早石炭世晚期大塘期以及西欧维宪期典型属种，又有南半球澳大利亚（包括巴西和非洲大陆）的维宪期的典型种。从孢子化石混合现象看，永珠组应为近岸浅水或滨海条件下的沉积，下伏地层的孢子化石再沉积现象说明当时有一次很大的海平面下降，在邻近地区出现了大面积的剥蚀区。说明杜内期末期一维宪期初期，申扎地区出现一次由冈瓦纳大陆冰川发育造成海平面相对下降。形成区域上不整合界面——洛工组或“巴日阿朗寨段”底部的不整合界面。混合孢子组合中的寒冷气候条件下的孢子化石的发现，印证了杨式溥、范影年和林宝玉推断的冈瓦纳冰川自早石炭世维宪期（大塘期）开始就影响到西藏申扎的推论。

英文摘要：

This paper reports the miospore assemblage of the lower part of the Yongzhu Formation, Xianza District, Northern Xizang （Tibet）. The age of the lower part of the Yongzhu Formation is late Early Carboniferous （Visean） based on the ammonites, conodonts, corals and brachiopods. Abundant miospores and some acritarchs are found in the silty mudstone of the lower part of Yongzhu Formation. 43 genera and more than 70 species are recognized. The characteristics of the miospore assemblage are as follows： （1） The Genus Lycospora is absent, which is a typical representative in the Euro-America plant province in the Early Carboniferous （Visean）. Besides, some of the important genera such as Schulzospora, Tripartites, Murospora, Tricidulus, Mooreisporites, Savitrisporites, Simezonotriletes, Reinschospora, Diatomozonotriletes, Alatisporites and Specerisporites are absent. （2） The redeposits of older miospores are one of the distinguished characters of the present assemblage. Some elements of the Late Devonian were also found, such as Lophozonotriletes lebedinganensis Naumova. A lot of elements of the early Early Carboniferous （Tournaisian） were found, such as： Raistrickia clarata （ Hacquebard） Playford, Baculatisporites fusticulus Sullivan, Apiculiretusispora fructicosa Higgs, Verrucosisporites depressus Winlsow, Acanthotriletes socraticus Neves and Ioannides, A. cf. ignatus Kedo, Lophozonotriletes bellus Kedo, Asperispora acuta （Kedo ） Van Der Zwan, Convolutispora tschernyschens （Kedo ） Gao comb. nov. , Dictyotriletes trivialis Naumova in Kedo, ？ Reticulatisporites fimbriatus Winlsow, Grandispora tenuispina （Hacquebard） Playford, G. echinatus Hacquebard, Densosporites variabilis （Waltz） Potonie and Kremp, Hymenozonotriletes ex- planatus （Luber） Kedo, Rugospora poluptycha Neves and Ioannides, Tumulispora varituberculata （ Luber ） Potonie, T. variverrucata （Playford） Staplin and Jansonius, Spelaeotriletes resolutus Higgs, S. resolatus Higgs, S. crustatus Higgs,