THE REDISCOVERY OF THE PLIOCENE FLORA FROM MT.CHO OYU,CENTRAL HIMALAYA AND ITS CHARACTERISTICS
This paper describes a plant macrofossil assemblage from the Pliocene strata of the Jiabula Formation,which is a lacustrine deposite,located on Mt.Cho Oyu in the central Himalaya(28° 28′ 1 2″N,86°58′64″E),enhancing our understanding of the region's paleoclimate and paleovegetation.Fieldwork conducted in 2023 collected 533 fossil specimens from two stratigraphic sections,and the measured thicknesses are 32.5 m and 35.25 m respectively within the Jiabula Formation.These specimens,encompassing various plant parts(branches,leaves,seeds,fruits,etc.),were identified using detailed morphological comparisons with extant relatives.The Jiabula flora comprises 19 species across 17 genera in 13 families,including Equisetum,Picea,Cupressus,Potamogeton,Berberis,Batrachium,Caragana,Argentina,Cotoneaster,Sorbus,Potentilla,Dasiphora,Hippophae,Alnus,Populus,Rhododendron,Lonicera.The fossil assemblage reveals a Picea-dominated landscape,with a variety of life forms,from coniferous trees and broad-leaved angiosperms to shrubs and herbaceous plants suggesting a forested landscape with distinct vertical vegetation zonation.Cold-tolerant alpine shrubs likely dominated higher altitudes,while warm-temperate taxa occupied lower elevations.The fossil evidence reveals a Pliocene landscape with vertically zoned vegetation,reflecting a warmer and wetter climate than that of the present.The rediscovery of diverse taxa within the Jiabula flora underscores the role of climate and topographic uplift in shaping the region's vegetation history.The vegetation patterns indicated by the Jiabula flora differ markedly from present-day alpine meadows in the region,highlighting significant climatic shifts since the Pliocene.Additionally,the presence of morphologically diverse,cold-and drought-resistant genera such as Caragana and Dasiphora suggests that the region was already experiencing aridification due to the uplift of the Himalayas.These findings align with other paleobotanical studies from adjacent areas,indicating a progressive shift from warm-temperate coniferous forests to the cold-adapted alpine meadows seen today,influenced by the uplift of the Himalayas and the intensification of aridification.
万方数据
维普
