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鄂尔多斯盆地西南部西峰油田中上三叠统延长组长8段和长7段钻井岩心中发现丰富的孢粉化石,分别命名为Aratisporites-Punctatisporites组合和Asseretospora-Walchiites组合,组合特征分别与盆地东南部发现的铜川组孢粉组合和延长组孢粉组合相似,地质时代分别为中三叠世晚期Ladinian期与晚三叠世早期Carnian期。通过孢粉植物群类型地层分布特征及其生态环境讨论,推测盆地区中晚三叠世气候温暖潮湿,雨量充沛,植被茂盛。孢粉植物群所反映的古气候为温带—亚热带暖湿或湿热气候。这是由于本地区当时处于较低的纬度,且濒临大型湖泊,而长8—长7段沉积时期正处于湖泊扩张的鼎盛期。
Abundant sporo-pollen fossils are found in drilling cores of Chang 8 and Chang 7 of the Upper Triassic Yanchang Formation in the Xifeng Oil Field, southwestern Ordos Basin. They are named as Aratisporites-Punctatisporites and Asseretospora-Walchiites, respectively, and their assemblages are closely related to the southeastern part of the basin The discovered sporopollen assemblages in the Tongchuan Formation are similar to the sporopollen assemblages in the Yanchang Formation. The geologic times are the Late Middle Triassic Ladinian and Early Late Triassic Carnian. According to the stratigraphic distribution characteristics of the pollen flora and its ecological environment, it is speculated that the mid-late Triassic climate in the basin is warm and humid with abundant rainfall and luxuriant vegetation. The paleoclimate represented by the pollen flora is temperate-subtropical warm-humid or humid-hot climate. This is because the region was at a lower latitude and was on the verge of a large lake, while the deposition period of Chang 8 to Chang 7 was in its prime of lake expansion.