scholarly journals Post-Pliocene establishment of the present monsoonal climate in SW China: evidence from the late Pliocene Longmen megaflora

2013 ◽  
Vol 9 (2) ◽  
pp. 1675-1701 ◽  
Author(s):  
T. Su ◽  
F. M. B. Jacques ◽  
R. A. Spicer ◽  
Y.-S. Liu ◽  
Y.-J. Huang ◽  
...  
Keyword(s):  
Tibet Plateau ◽  
Leaf Margin ◽  
Late Pliocene ◽  
Leaf Analysis ◽  
Asian Winter Monsoon ◽  
Monsoon Index ◽  
Coexistence Approach ◽  
Western Yunnan ◽  
Qinghai Tibet Plateau ◽  
Margin Analysis

Abstract. The paleoclimate of the late Pliocene Longmen flora from Yongping County located at the southeastern boundary of the Qinghai-Tibet Plateau was reconstructed using two leaf physiognomy based methods, i.e. Leaf Margin Analysis (LMA) and Climate Leaf Analysis Multivariate Program (CLAMP), to understand the paleoclimate condition and geographical pattern of monsoonal climate in southwestern China during the late Pliocene. The mean annual temperatures (MATs) estimated by LMA and CLAMP are 17.4 ± 3.3 °C and 17.4 ± 1.3 °C, respectively, compared with 15.9 °C at present. Meanwhile, the growing season precipitation (GSP) estimated by CLAMP is 1735.5 ± 217.7 mm in the Longmen flora, compared with 986.9 mm nowadays. The calculated monsoon index (MSI) of the Longmen flora is significantly lower than that of today. These results appear consistent with previous studies based on the coexistence approach (CA), and further suggest that there was a slightly warmer and much wetter climate during the late Pliocene than the present climate in western Yunnan. We conclude that the significant change of the monsoonal climate might have been resulted from the continuous uplift of mountains in western Yunnan, as well as the intensification of eastern Asian winter monsoon, both occurring concurrently in the post-Pliocene period.

scholarly journals Post-Pliocene establishment of the present monsoonal climate in SW China: evidence from the late Pliocene Longmen megaflora

2013 ◽  
Vol 9 (4) ◽  
pp. 1911-1920 ◽  
Author(s):  
T. Su ◽  
F. M. B. Jacques ◽  
R. A. Spicer ◽  
Y.-S. Liu ◽  
Y.-J. Huang ◽  
...  
Keyword(s):  
Tibet Plateau ◽  
Leaf Margin ◽  
Late Pliocene ◽  
Leaf Analysis ◽  
Intensity Index ◽  
Asian Winter Monsoon ◽  
Coexistence Approach ◽  
Western Yunnan ◽  
Monsoon Intensity ◽  
Qinghai Tibet Plateau

Abstract. The paleoclimate of the late Pliocene Longmen flora from Yongping County located at the southeastern boundary of the Qinghai-Tibet Plateau was reconstructed using two leaf-physiognomy-based methods, i.e., leaf margin analysis (LMA) and Climate Leaf Analysis Multivariate Program (CLAMP), to understand the paleoclimate condition and geographical pattern of monsoonal climate in southwestern China during the late Pliocene. The mean annual temperatures (MATs) estimated by LMA and CLAMP are 17.4 ± 3.3 °C and 17.4 ± 1.3 °C, respectively, compared with 15.9 °C at present. Meanwhile, the growing season precipitation (GSP) estimated by CLAMP is 1735.5 ± 217.7 mm in the Longmen flora, compared with 986.9 mm nowadays. The calculated monsoon intensity index (MSI) of the Longmen flora is significantly lower than that of today. These results appear consistent with previous studies on the late Pliocene floras in western Yunnan based on the coexistence approach (CA), and further suggest that there was a slightly warmer and much wetter climate during the late Pliocene than the present climate in western Yunnan. We conclude that the significant change of the monsoonal climate might have been resulted from the continuous uplift of mountains in western Yunnan, as well as the intensification of the eastern Asian winter monsoon, both occurring concurrently in the post-Pliocene period.

scholarly journals Late Pliocene temperatures and their spatial variation at the southeastern border of the Qinghai–Tibet Plateau

2015 ◽  
Vol 111 ◽  
pp. 44-53 ◽  
Author(s):  
Yong-Jiang Huang ◽  
Wen-Yun Chen ◽  
Frédéric M.B. Jacques ◽  
Yu-Sheng Christopher Liu ◽  
Torsten Utescher ◽  
...  
Keyword(s):  
Spatial Variation ◽  
Tibet Plateau ◽  
Late Pliocene ◽  
Qinghai Tibet Plateau

When are leaves good thermometers? A new case for Leaf Margin Analysis

Paleobiology ◽  
1997 ◽  
Vol 23 (3) ◽  
pp. 373-390 ◽  
Author(s):  
Peter Wilf
Keyword(s):  
Species Richness ◽  
Multivariate Data ◽  
Species Abundance ◽  
Western Hemisphere ◽  
Mean Annual Temperature ◽  
Leaf Margin ◽  
Data Set ◽  
Leaf Analysis ◽  
Climate Analysis ◽  
Margin Analysis

Precise estimates of past temperatures are critical for understanding the evolution of organisms and the physical biosphere, and data from continental areas are an indispensable complement to the marine record of stable isotopes. Climate is considered to be a primary selective force on leaf morphology, and two widely used methods exist for estimating past mean annual temperatures from assemblages of fossil leaves. The first approach, Leaf Margin Analysis, is univariate, based on the positive correlation in modern forests between mean annual temperature and the proportion of species in a flora with untoothed leaf margins. The second approach, known as the Climate-Leaf Analysis Multivariate Program, is based on a modern data set that is multivariate. I argue here that the simpler, univariate approach will give paleotemperature estimates at least as precise as the multivariate method because (1) the temperature signal in the multivariate data set is dominated by the leaf-margin character; (2) the additional characters add minimal statistical precision and in practical use do not appear to improve the quality of the estimate; (3) the predictor samples in the univariate data set contain at least twice as many species as those in the multivariate data set; and (4) the presence of numerous sites in the multivariate data set that are both dry and extremely cold depresses temperature estimates for moist and nonfrigid paleofloras by about 2°C, unless the dry and cold sites are excluded from the predictor set.New data from Western Hemisphere forests are used to test the univariate and multivariate methods and to compare observed vs. predicted error distributions for temperature estimates as a function of species richness. Leaf Margin Analysis provides excellent estimates of mean annual temperature for nine floral samples. Estimated temperatures given by 16 floral subsamples are very close both to actual temperatures and to the estimates from the samples. Temperature estimates based on the multivariate data set for four of the subsamples were generally less accurate than the estimates from Leaf Margin Analysis. Leaf-margin data from 45 transect collections demonstrate that sampling of low-diversity floras at extremely local scales can result in biased leaf-margin percentages because species abundance patterns are uneven. For climate analysis, both modern and fossil floras should be sampled over an area sufficient to minimize this bias and to maximize recovered species richness within a given climate.

The intensification of the East Asian winter monsoon contributed to the disappearance of Cedrus (Pinaceae) in southwestern China

2013 ◽  
Vol 80 (2) ◽  
pp. 316-325 ◽  
Author(s):  
Tao Su ◽  
Yu-Sheng (Christopher) Liu ◽  
Frédéric M.B. Jacques ◽  
Yong-Jiang Huang ◽  
Yao-Wu Xing ◽  
...  
Keyword(s):  
East Asian Winter Monsoon ◽  
East Asian ◽  
Winter Monsoon ◽  
Southwestern China ◽  
Natural Forests ◽  
Climate Data ◽  
Late Pliocene ◽  
Asian Winter Monsoon ◽  
Western Yunnan ◽  
Fossil Records

Climate change during the Quaternary played an important role in the distribution of extant plants. Herein, cone scales of Cedrus (Pinaceae) were uncovered from the Upper Pliocene Sanying Formation, Longmen Village, Yongping County of Yunnan Province in southwestern China. Detailed comparisons show that these fossils all belong to the genus Cedrus (Pinaceae), and a new species is proposed, Cedrus angusta sp. nov. This find expands the known distribution of Cedrus during the Late Pliocene to Yunnan, where the genus no longer exists in natural forests. Based on the analysis of reconstructed Neogene climate data, we suggest that the intensification of the East Asian winter monsoon during the Quaternary may have dramatically increased seasonality and given rise to a much drier winter in Yunnan. Combined with information on Cedrus fossil records and its seed physiology, we conclude that the intensification of a drier climate after the Late Pliocene may have prevented the survival of Cedrus seedlings, leading to the eventual disappearance of Cedrus in western Yunnan. This study indicates that the topography in southwestern China acted as a vital refuge for many plants during the Quaternary, but that other species gradually disappeared due to the intensification of the monsoonal climate.

The Kanaka Creek fossil flora (Huntingdon Formation), British Columbia, Canada — paleoenvironment and evidence for Paleocene age using palynology and macroflora

2020 ◽  
Vol 57 (3) ◽  
pp. 348-365
Author(s):  
Rolf W. Mathewes ◽  
David R. Greenwood ◽  
Renée L. Love
Keyword(s):  
British Columbia ◽  
Fungal Spores ◽  
Plant Macrofossils ◽  
Coastal Vegetation ◽  
Mean Annual Precipitation ◽  
Fossil Flora ◽  
Leaf Margin ◽  
Leaf Analysis ◽  
Thermal Maximum ◽  
Margin Analysis

Paleogene sediments of the Huntingdon Formation, a correlative to the Chuckanut Formation of neighbouring Washington State, USA, are exposed in the Greater Vancouver area, British Columbia, Canada. Palynology and plant macrofossils suggest the Kanaka Creek section is Paleocene rather than Eocene in age. Detrital zircon dating is less decisive, yet indicates the Kanaka rocks are no older than Maastrichtian. Analyses of plant macro- and micro-fossils suggest an early to middle Paleocene age for the Kanaka fossil flora. Paleocene indicators include macrofossils such as Platanus bella, Archeampelos, Hamamelites inequalis, and Ditaxocladus, and pollen taxa such as Paraalnipollenites, Triporopollenites mullensis, and Duplopollis. Paleogene taxa such as Woodwardia maxonii, Macclintockia, and Glyptostrobus dominate the flora. Fungal spores including the Late Cretaceous Pesavis parva and the Paleogene Pesavis tagluensis are notable age indicators. Physiognomy of 41 angiosperm leaf morphotypes from Kanaka Creek yields mean annual temperatures in the microthermal to lower mesothermal range (11.2 ± 4.3 to 14.6 ± 2.7 °C from leaf margin analysis; 14.8 ± 2.1 °C from Climate Leaf Analysis Multivariate Program), with mild winters (cold month mean temperature 3.9 ± 3.4 °C). Paleoclimate was cooler than the upper Paleocene and Eocene members of the Chuckanut Formation. Mean annual precipitation is estimated at ∼140 cm with large uncertainties. The Kanaka paleoflora is reconstructed as a mixed conifer–broadleaf forest, sharing common taxa with other western North American Paleocene floras and growing in a temperate moist climate. Kanaka Creek is a rare coastal Paleocene plant locality that provides new insights into coastal vegetation and climate prior to the Paleocene–Eocene Thermal Maximum.

The Neogene wood flora of Yuanmou, Yunnan, southwest China

IAWA Journal ◽  
2018 ◽  
Vol 39 (4) ◽  
pp. 427-474
Author(s):  
Ye-Ming Cheng ◽  
Yu-Fei Wang ◽  
Feng-Xiang Liu ◽  
Yue-Gao Jin ◽  
R. C. Mehrotra ◽  
...  
Keyword(s):  
Coniferous Forest ◽  
Lacustrine Sediments ◽  
Tibet Plateau ◽  
Southeastern Part ◽  
Vegetation Zones ◽  
Broad Leaved Forest ◽  
Western Yunnan ◽  
The Indian Ocean ◽  
Qinghai Tibet Plateau ◽  
Leaved Forest

ABSTRACTThe Pliocene fluvio-lacustrine sediments of the Yuanmou Basin, Yunnan, near the southeastern part of Qinghai-Tibet Plateau, China, have yielded diverse and abundant assemblages of fossilized mammals and woods. The Yuanmou fossil woods reveal a wood flora with the highest diversity in the Cenozoic wood in China. The woods can play an important role in understanding palaeofloristics and in reconstructing palaeoclimate of southeastern China. In this study, we describe ten angiosperm taxa and three gymnosperm taxa namely: Castanopsis makinoi (Ogura) Suzuki & Terada (Fagaceae), Cedreloxylon cristalliferum Selmeier (Meliaceae), Dalbergioxylon biseriatensis sp. nov. (Fabaceae), Lagerstroemioxylon yuanmouensis Cheng, Li, Jiang & Wang (Lythraceae), Lithocarpoxylon microporosum sp. nov., Lithocarpoxylon sp. (Fagaceae), Paraalbizioxylon sinica sp. nov., P. yunnanensis sp. nov. (Fabaceae), Pterocaryoxylon huxii sp. nov. (Juglandaceae), Zelkova wakimizui (Watari) Watari (Ulmaceae), Abies sp. (Pinaceae), Cephalotaxus sp. (Cephalotaxaceae), and Picea sp. (Pinaceae). Nearest living relative (NLR) comparisons of these taxa, coupled with previously identified taxa, suggest that altitudinal vegetation zones were present in the Yuanmou region during the Pliocene: (i) subtropical evergreen and deciduous mixed broad-leaved forest dominated by Pterocarya/Juglans, Albizia/Acacia, Bischofia and allied taxa at lower elevations, (ii) subtropical evergreen broad-leaved forest dominated by Quercus/Lithocarpus and Castanopsis at middle altitudes of mountains around the basin, and (iii) evergreen coniferous forest of Abies, Picea and other genera at the higher elevations of the mountains. Based on the habits of the NLRs, the prevailing climate was probably humid subtropical and thus differed from the present-day hot and dry climate supporting savanna. It is suggested that subtropical forest was predominant in Yunnan, while tropical rainforest occurred in southwest Asia and India during the same period. The uplift of the mountains near the Qinghai-Tibet plateau in western Yunnan presumably acted as a barrier to block warm and humid air from the Indian Ocean, which influenced the dispersal and distribution of plants.

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