Palynoflora from the lower Jurassic Fuxian Formation in Ordos basin and its response to the Jenkyns event
For researching the influence of Jenkyns event on the paleoclimate of inland basins,we analysis the palynological characteristics of Fuxian Formation in the southern Ordos basin.Three palynological assemblage were divided from bottom to top as:Cyathidites-Deltoidospora-Chasmatosporites assemblage,whose age is the Pliensbachian of early Jurassic;Classopollis-Quadraeculina-Chasmatosporites assemblage,whose age is the early-mid Toarcian of the early Jurassic,which coincides with the Jenkyns event;Cyathidites-Cycadopites-Psophosphaera assemblage whose age is the late Toarcian of early Jurassic.The paleoclimate reflected by sporopollen community shows that the Ordos basin experienced the transformation as subtropical humid climate→subtropical semi-humid and semi-arid climate →subtropical humid climate during the early Jurassic Fuxian period.Different from the previous conclusions of the Tethys Oceanic and Pan-Oceanic studies,the Jenkyns event appears as a drying and heating event in the Ordos basin(the hinterland of Eurasia).
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