More Sandip, Paruya Dipak Kumar, Taral Suchana, Chakraborty Tapan, Bera Subir
Centre of Advanced Study, Department of Botany, University of Calcutta, 35, Ballygunge Circular Road, Kolkata, 700019, West Bengal, India.
Geological Studies Unit, Indian Statistical Institute, 203, B.T. Road, Kolkata, 700108, West Bengal, India.
PLoS One. 2016 Mar 1;11(3):e0150168. doi: 10.1371/journal.pone.0150168. eCollection 2016.
A rich and diverse palynoassemblage recovered from the Churanthi River section (26°53' 59.3" N, 88°34' 17.2" E), Darjeeling foothills Eastern Himalaya, has yielded 87 species assigned to 69 genera. The palynoassemblage is rich in angiosperm taxa (45.63%) followed by gymnosperms (0.45%), pteridophytes (18.49%) and fungal remains (23.88%). Based on their nearest living relatives, a wet evergreen to semi-evergreen forest under a humid tropical to sub-tropical environment during the Mio-Pliocene age has been suggested. A lot of angiosperms such as Palaeosantalaceaepites, Araliaceoipollenites, Malvacearampollis, Zonocostites, Neocouperipollis, Dicolpopollis, Palmidites, Palmaepollenites, isolated salt glands of mangrove plant leaves (Heliospermopsis) and Mediaverrunites type of fungal spores, along with ichnofossils like Planolites, Palaeophycus, Skolithos, Rosselia, Ophiomorpha and Teichichnus associated with rippled mudstone-siltstone suggest an environment strongly influenced by brackish water. Primary sedimentary structures in the associated strata indicate strong wave agitation common in shallow marine setting. Some high elevation components (5.14%) such as Alnipollenites, cf. Corylus (Betulaceae), Juglanspollenites, Engelhardtioipollenites (Juglandaceae), Quercoides, Cupuliferoidaepollenites, Lithocarpus, Castanopsis (Fagaceae), Abietineaepollenites (Pinaceae) represent hinterland vegetation possibly transported to the prograding deltaic coastline by the rivers. Reworked palynotaxa (Striatopodocarpites sp., Striatites sp., Faunipollenites sp., Circumstriatites sp., Crescentipollenites sp., Cuneatisporites sp., Parasaccites sp., Scheuringipollenites sp., Rhizomaspora sp., Marsupipollenites sp., Lophotriletes sp.) of Permian age have also been recorded in the palynoassemblage (11.55%) indicating the abundance of Permian Gondwana strata in the source area.
从喜马拉雅山东部大吉岭山麓楚兰蒂河段（北纬26°53′59.3″，东经88°34′17.2″）发现的丰富多样的孢粉组合，已鉴定出69个属的87个物种。该孢粉组合中被子植物类群丰富（45.63%），其次是裸子植物（0.45%）、蕨类植物（18.49%）和真菌残骸（23.88%）。根据其最近的现存亲缘关系，推测在中新世 - 上新世时期，该地区处于湿润的热带至亚热带环境下，存在着从湿润常绿到半常绿的森林。许多被子植物，如古檀香科孢粉、五加科花粉、锦葵科花粉、带肋花粉、新库珀粉、双沟粉、掌形花粉、棕榈科花粉、红树林植物叶的孤立盐腺（太阳花粉属）和中穴孢类型的真菌孢子，以及与波状泥岩 - 粉砂岩相关的遗迹化石，如迹痕化石、古藻迹、石针迹、罗斯氏迹、蛇形迹和苔藓虫迹，表明该环境受到微咸水的强烈影响。相关地层中的原生沉积构造表明，浅海环境中常见强烈的波浪搅动。一些高海拔成分（5.14%），如桤木粉、拟榛属（桦木科）、胡桃粉、黄杞粉（胡桃科）、栎粉属、壳斗科花粉、石栎属、锥属（壳斗科）、冷杉粉属（松科），代表了内陆植被，可能是由河流输送到不断推进的三角洲海岸线上的。在孢粉组合中（11.55%）还记录到了二叠纪的再沉积孢粉分类群（条纹 Podocarpites 属、条纹孢属、动物花粉属、环纹孢属、新月形花粉属、楔形孢属、副囊粉属、舍林粉属、根状孢属、有袋花粉属、冠三缝孢属），这表明源区中二叠纪冈瓦纳地层丰富。
