Leaf Margin Analysis Research Articles

A Paleogene leaf flora (Profen, Sachsen-Anhalt, Germany) and its potentials for palaeoecological and palaeoclimate reconstructions

Leaves as main locations of photosynthesis show various adaptations of morphological and anatomical traits to habitat conditions. By implication, leaf traits of fossil dicotyledonous plants can be used as proxies for reconstructions of palaeoenvironmental and palaeoclimatic conditions. Herein, a Paleogene leaf flora, the Profen-Süd LC assemblage from central Germany, is introduced and its leaf traits are outlined. Based on a preliminary phytosociological analysis, a floristic evaluation with respect to modern comparative vegetation refers to azonal communities predominated by a Rhodomyrtophyllum-Steinhauera riparian association. It mirrors local rather but species-divers vegetation. Morphological (shape; margin; venation) and morphometrical (area; leaf mass per area) leaf parameters are determined on a representative subsample and applied to the Trait Combination Type (TCT) analysis for gross-morphological characterization of fossil leaf assemblages, and to quantitative methods for estimation of palaeoclimate parameters: Climate Leaf Analysis Multivariate Program, Coexistence Approach and Leaf Margin Analysis. As a result the assemblage contains only four out of 16 TCTs. Morphological diversity is assumed to be characteristically low as the TCT pattern is not fundamentally distinct from that of the coeval hinterland flora of Kučlin (Czechia). Leaf size is overwhelmingly microphyll, and leaf mass per area values are in accordance with present-day evergreen forests. Main results refer to a sclerophyllous evergreen broad-leaved forest. All palaeoclimate calculations deliver similar estimates for subtropical climate with frost-free winters and humid conditions but certain seasonality in precipitation. Results are briefly discussed in context to depositional environment and taphonomic aspects. Moreover, traces of insect herbivory on the fossil leaves are treated as additional traits beyond classical parameters. Respective patterns are briefly documented and discussed to obtain deeper insights into ecosystem structure and food webs. Finally, this case study gives rise to several open questions about reliability and meaningfulness of fossil leaf traits and the feasibility in palaeoecological investigations.

Warm climate under high CO2 level in the early Pleistocene based on a leaf fossil assemblage in central Japan

The atmospheric levels of CO2, a greenhouse gas, are closely related to global change, and investigation of historic CO2 levels can help achieve a better understanding of the global climate change in the deep past. While stomatal frequency of fossil leaves has been recurrently used for palaeo-CO2 reconstruction, simultaneous investigation of both palaeo-temperature and palaeo-CO2 using the same fossil assemblage has been rarely performed. In this study, based on the stomatal analyses of Quercus gilva from a leaf bed in the Sayama Formation (1.66–1.55 Ma) in central Japan, we estimated the palaeo-CO2 values in an interglacial stage (MIS 57 or 55) at 36.41 ± 2.58 pa, which is generally higher than the previously reported data from early Pleistocene. To understand the climate under this high CO2 level, we also calculated the mean annual temperature (MAT) based on the same leaf assemblage using the leaf margin analysis (LMA) approach. The calculated MAT was 11.0 °C, suggesting a relatively warm climate during the interglacial stage. Our results revealed a warm environment under high CO2 level during the early Pleistocene, which demonstrates the vital role of CO2 in controlling the early Pleistocene interglacial temperature.

Early Miocene climate estimations in Patagonia: The case of Pico Quemado, Ñirihuau Formation (Lower-Middle Miocene)

The climate during the early Neogene in Patagonia is characterized by the increase of the average temperatures until the mid-Miocene Climatic Optimum. However, the terrestrial paleoclimate of southern South America during this period is unclear. Therefore, a physiognomic analysis on the Pico Quemado (Ñirihuau Formation, lower-middle Miocene) megaflora was realized. Three types of analyses were performed: 1) Leaf Margin Analysis (LMA); 2) Leaf Area Analysis (LAA); and 3) a CLAMP analysis (Climate Leaf Analysis Multivariate Program) with two different dataset. The LMA and CLAMP predicted an estimated a Mean Annual Temperature of 10.4 ± 2.1 °C, 8.5 ± 2.1 °C and 7.2 ± 1.4 respectively. The estimations of Mean Annual Precipitation were of 123.7 ± 21.2 cm. Through the CCA, other parameters were estimated, i. e. Cold Mean Month Temperature (−3.3 ± 3.8 °C, 1.6 ± 1.6 °C); Warm Mean Month Temperature (17.4 ± 3.3 °C; 14.1 ± 1.2 °C); Mean Growing Season Precipitation (121.9 ± 42.6 cm; 78.1 ± 42.6 cm); Precipitation of the Three Consecutive Wettest Months (116.2 ± 15.3 cm; 88.5 ± 15.3 cm); and Precipitation of the Three Consecutive Driest Months (40.2 ± 19.8 cm; 54.1 ± 19.8 cm). From these results, the Pico Quemado megaflora can be characterized as having a cool temperate climate, with moderate precipitations and the development of bi-seasonality. The obtained estimations are concordant with previous morphological studies in Pico Quemado, which had proposed the same climate conditions. However, these results are inconsistent compared to other studies of early Neogene Southern Hemisphere that suggest that the climate could be warmer. This difference might be due to the few studies of climatic estimations during the early Neogene in Patagonia, precluding detailed comparisons. In conclusion, Pico Quemado paleoflora exhibits unique climatic conditions, and also floral compositions, as suggested in previous works and here corroborated. The study realized constitutes the first climatic estimations for an Argentinean megaflora developed during the Neogene.

Interpretações paleoclimáticas a partir da flora pliocênica de Nova Iorque, Maranhão, Brasil

The Nova Iorque fossil flora, located in northeastern Brazil, is the only fossil flora known for the Pliocene of the Nova Iorque Basin. Because the paleobotanical records in the areas populated by the Caatinga vegetation are scarce, this flora is very important to understand the climatic and environmental changes that occurred in northeastern Brazil. The main physiognomic characteristics – margin type and leaf area – of the angiosperm leaves of 26 species of this flora, allowed us to carry out a quantitative estimation of mean annual temperature (MAT) and mean annual precipitation (MAP) for the moment of its sedimentation. The different equations used to estimate the MAT and the MAP are based on univariate methods known as Leaf Margin Analysis and Leaf Area Analysis. The equations used indicate that the Nova Iorque fossil flora developed under a MAT between 26.1 and 26.7°C and a MAP between 580 and 833 mm. These values are very similar to those currently registered in the region where the Nova Iorque fossil flora is located; therefore, this flora lived under a climate similar to that of the Caatinga, which is characterized by being warm and semi-arid. Because this fossil flora has developed under conditions similar to those of the current flora, it is possible to infer that this flora represents a precursor of a phytophysiognomy of the Caatinga.

Leaf margin analysis of Chinese woody plants and the constraints on its application to palaeoclimatic reconstruction

AbstractAimLeaf margin states have been found to be strongly related to temperature, and hence have been used to reconstruct palaeotemperatures. Here, we aimed to explore the uncertainties and conditions of use of this technique in China by testing the influences of plant life‐form, precipitation and evolutionary history on the relationship between percentage of untoothed species and temperature.LocationChina.MethodsUsing distribution maps and leaf margin states (untoothed versus toothed) of 10,480 Chinese woody dicots and dated family‐level phylogenies, we evaluated the phylogenetic signal of leaf margin state, and demonstrated the variation in the patterns of leaf margin percentage and the relationship with temperature across different life‐forms (evergreen and deciduous; trees, shrubs and lianas), regions with different precipitation and species quartiles with different family ages.ResultsSignificant phylogenetic signals were found for the percentage of untoothed species within families. Relationships between leaf margin percentage and temperature were: (1) weak or insignificant for all woody dicots, shrubs, evergreen and deciduous dicots, but strong for trees and lianas; (2) significantly enhanced with increasing precipitation, and (3) significantly weakened for trees belonging to old families.Main conclusionsOur results showed the complete leaf margin spectrum found in China and revealed great uncertainties in its relationship with temperature induced by life‐form, precipitation and evolutionary history. These findings suggest that analysis of leaf margins for palaeotemperature reconstruction should be done cautiously: (1) only dicot trees with a relatively young family age can be used and their leaf margin states are more strongly affected by winter cold than by mean annual temperature; (2) the transfer function between leaf margin percentage and temperature is only reliable in humid and semi‐humid regions of China.

Paleoenvironment of the Quilchena flora, British Columbia, during the Early Eocene Climatic Optimum

The Quilchena fossil locality is dated (51.5 ± 0.4 Ma) to the Early Eocene Climatic Optimum, and this locality is reconstructed as the warmest and wettest of the Early Eocene upland sites from the Okanagan Highlands of British Columbia and northern Washington State. Mean annual temperature (MAT) is estimated from leaf margin analysis, using 55 dicot morphotypes, as 16.2 ± 2.1 °C/14.6 ± 4.8 °C. Using bioclimatic analysis of 45 nearest living relatives, a moist mesothermal climate is indicated (MAT 12.7–16.6 °C; cold month mean temperature (CMMT) 3.5–7.9 °C; mean annual precipitation (MAP) 103–157 cm/year. Leaf size analysis estimates MAP at 121 ± 39 cm/year. Estimates from the climate leaf analysis multivariate program corroborate these results, although with a slightly cooler MAT (13.3 ± 2.1 °C). Plants that support an interpretation of warm winters with minimal or no frost include Azolla, Glyptostrobus, Taxodium, Keteleeria, Pseudolarix, Eucommia, Dipteronia, Hovenia, Ternstroemia, and others. These thermophilous elements occur together with temperate genera such as Alnus, Betula, Ulmus, Calocedrus, and Fraxinus. Palynological assemblages at Quilchena are dominated by bisaccate conifers and Cupressaceae. Common angiosperms include Ulmus type, triporates, Pterocarya, and Alnus. Insect fossils at Quilchena that today inhabit tropical and subtropical regions also support warm and equable climate without significant frost, and include obligate palm-feeding beetles (Pachymerina), which indicate CMMT perhaps as high as 8 °C. These are found together with temperate aphids, wasps, giant lacewings, brown lacewings, and a panorpoid scorpionfly, supporting an interpretation of equable climatic conditions during the Early Eocene Climatic Optimum.

Plant megaflora from the Siwalik (Upper Miocene) of Darjeeling District, West Bengal, India and its palaeoclimatic and phytogeographic significance

Qualitative and quantitative analysis of fossil assemblage so far collected from the Middle Siwalik sediments of Darjeeling District, West Bengal revealed the occurrence of 35 new taxa belonging to 18 angiospermous families. On the basis of present data as well as already known data from there, the reconstruction of vegetation scenarios of Himalayan foothills during Siwalik time has been done. We also discussed problems related to plant diversity, endemism, and migratory pathways of mainly phytogeographically important taxa. The analysis of present day distribution of all the recovered taxa from the region shows that they are mostly known to occur in Northeast India, Bangladesh, Myanmar and the Malayan region where the climatic conditions are favourable. About 1/3 taxa of total assemblage are found to grow presently in the Himalayan foothills of the eastern region and the remaining 2/3 taxa are locally extinct. This indicates that the climatic changes must have taken place after Mio–Pliocene. The dominance of evergreen elements in present fossil assemblage indicates the prevalence of tropical warm humid climate with plenty of rainfall during the deposition of sediments. Foliar physiognomic approach for reconstruction of palaeoclimate further suggests that the Oodlabari area in the Himalayan foothills of West Bengal enjoyed a tropical climate (with MAT 28.9º C and MAP 448 mm) during the Miocene Period. This is, however, contrary to the present day climate of the area with reduced precipitation. On the basis of the present fossil assemblage, the coexistence intervals of different climatic parameters, i.e. Mean Annual Temperature (MAT), Warmest Month Temperature (WMT), Coldest Month Temperature (CMT), and Mean Annual Precipitation (MAP) have been estimated as 22º C–26.5º C, 17.8º C–20º C, 25º C–30º C, and 2650–3200 mm, respectively. However, Leaf Margin Analysis (LMA) suggests the MAT value as 28.9º C for the area during Upper Miocene.

Stable isotope paleoclimatology of the earliest Eocene using kimberlite-hosted mummified wood from the Canadian Subarctic

Abstract. The recent discovery of well-preserved mummified wood buried within a subarctic kimberlite diamond mine prompted a paleoclimatic study of the early Eocene "hothouse" (ca. 53.3 Ma). At the time of kimberlite eruption, the Subarctic was warm and humid producing a temperate rainforest biome well north of the Arctic Circle. Previous studies have estimated that mean annual temperatures in this region were 4–20 °C in the early Eocene, using a variety of proxies including leaf margin analysis and stable isotopes (δ13C and δ18O) of fossil cellulose. Here, we examine stable isotopes of tree-ring cellulose at subannual- to annual-scale resolution, using the oldest viable cellulose found to date. We use mechanistic models and transfer functions to estimate earliest Eocene temperatures using mummified cellulose, which was well preserved in the kimberlite. Multiple samples of Piceoxylon wood within the kimberlite were crossdated by tree-ring width. Multiple proxies are used in combination to tease apart likely environmental factors influencing the tree physiology and growth in the unique extinct ecosystem of the Polar rainforest. Calculations of interannual variation in temperature over a multidecadal time-slice in the early Eocene are presented, with a mean annual temperature (MAT) estimate of 11.4 °C (1 σ = 1.8 °C) based on δ18O, which is 16 °C warmer than the current MAT of the area (−4.6 °C). Early Eocene atmospheric δ13C (δ13Catm) estimates were −5.5 (±0.7) ‰. Isotopic discrimination (Δ) and leaf intercellular pCO2 ratio (ci/ca) were similar to modern values (Δ = 18.7 ± 0.8 ‰; ci/ca = 0.63 ± 0.03 %), but intrinsic water use efficiency (Early Eocene iWUE = 211 ± 20 μmol mol−1) was over twice the level found in modern high-latitude trees. Dual-isotope spectral analysis suggests that multidecadal climate cycles somewhat similar to the modern Pacific Decadal Oscillation likely drove temperature and cloudiness trends on 20–30-year timescales, influencing photosynthetic productivity and tree growth patterns.

Estimation of late Eocene (Bartonian–Priabonian) terrestrial palaeoclimate: Contributions from megafloral assemblages from central Germany

Abstract The Eocene, the world’s last global greenhouse period, shows distinct climatic developments through time, from subtropical towards warm-temperate conditions in Europe. The present paper investigates the response of five floras of the central German Weiselster Basin from different stratigraphic ages to terrestrial palaeoclimatic variations. The floras were selected from the Zeitz Floral Assemblage (“Florenkomplex”) and cover a time interval of ca. 3.5 Myr within the late Eocene, which is supposed to be a period of gradual decline of global mean annual temperatures. The Zeitz Floral Assemblage was characterized by mainly evergreen, notophyllous intrazonal vegetation, consisting of subtropical and warm-temperate elements. The five floras as well as the entire Zeitz Floral Assemblage have been analysed using the following quantitative techniques: leaf margin analysis (LMA), Climate Leaf Analysis Multivariate Program (CLAMP) and Coexistence Approach (CA). Furthermore, the results have been compared with previously published estimates for additional localities from the same area and age. The temperature estimates derived for the Zeitz Floral Assemblage are in a good agreement with those of previous studies i.e. mean annual temperature (MAT) 16.1–20.0 °C, warmest month mean temperature (WMMT) 24.9–26.4 °C, coldest month mean temperature (CMMT) 9.2–13.3 °C. Deviations have been determined for the calculated mean annual precipitation (MAP 1308–1335 mm) compared to previously published data, indicating values of about 2000 mm. Both CLAMP and CA reveal clear hints for seasonality in precipitation which is in agreement with previous phytosociological assumptions and palynological data. The estimates for the individual sites differ between the different techniques as well as among the individual sites, but generally indicate no temporal trends in temperature and precipitation development. Additionally, the applicability of these techniques for fluvial-estuarine plant assemblages, as well as the applicability of intrazonal vegetation for reconstructing transregional climate conditions are discussed. Taphonomic and methodical biases are also subject of debate.

Is climate warming advantageous for plants with untoothed leaves?

The percentage of dicotyledonous species with untoothed leaf margins is positively correlated with mean annual temperature across different continents and biomes. Paleobotanists commonly use this relationship as an index for inferring temperature in the past. However, leaf margin analysis often estimates cooler temperatures than alternative methods. Therefore, the following research hypothesis was stated: due to the observed climate warming, species with untoothed leaves are in better ecological status than species with toothed leaves. Responses of flora to global warming were studied for species with toothed vs. untoothed leaf margins after assigning species to the following categories based on data in the literature: (1) frequency; (2) population trends; (3) degree of endangerment; and (4) protected plants. A total of 2388 dicotyledonous woody and herbaceous plant species of Central Europe (separately from Germany and Poland) were analysed. The results were very similar in both analysed countries and for herbaceous and woody species. Contrary to assumptions, it was found that untoothed species clearly dominate in rare, disappearing, endangered, and protected plant groups. In contrast, plants with toothed leaf margins dominate in frequent and widespread species. The possible explanation is a delay in the response of local flora to climate change. This suggests a post-glacial relict nature of many species with untoothed leaves exists, persisting in local flora from the time of warmer periods. The constant error of underestimating past temperatures using the leaf margin method may explain the impact of today's flora in the models used because modern flora have more species with toothed leaves than expected. Taking into account the delayed reaction of flora to climate change may increase the accuracy of models predicting the climate in the past and in the future.

Paleoclimatic reconstruction for the Albian–Cenomanian transition based on a dominantly angiosperm flora from the Cedar Mountain Formation, Utah, USA

The Soap Wash flora from the Cedar Mountain Formation of Emery County, Utah (Albian–Cenomanian boundary) consists almost entirely of angiosperms and is positioned stratigraphically near the first appearance of flowering plants in this region. We applied both univariate (leaf margin analysis—LMA, and leaf area analysis—LAA) and multivariate (Climate Leaf Analysis Multivariate Program—CLAMP) methods to the 17 morphotypes recognized in the flora to reconstruct palaeoclimate. LMA produced a mean annual temperature (MAT) estimate ranging from 19 °C to 26 °C. CLAMP yielded 16 °C–18 °C. LAA produced a mean annual precipitation (MAP) of 81 cm, while CLAMP generated a mean growing season precipitation of 134–187 cm, within the range of standard error for the LAA estimation. CLAMP also estimated a nine to ten month growing season with some temperature seasonality and substantial seasonality in precipitation. This reconstruction is broadly consistent with sedimentological data that suggested a semiarid to monsoonal precipitation regime for the region and with climate models that predict warm summers and strong winter seasonality in precipitation. Leaf physiognomic parameters of the Soap Wash flora fall within the range of variation circumscribed by the calibration sets of all three methods, so the differences in reconstructed MAT values cannot be explained exclusively by this kind of systematic error. We propose two alternative hypotheses: First, modern leaf form-climate relationships may not yet have evolved. This seems unlikely because CLAMP has been successfully applied to older material elsewhere. Second, the Soap Wash flora may be out of equilibrium with its prevailing climate due to contemporaneous rapid climate flux. If correct, this pattern may suggest a link between mid-Cretaceous environmental perturbations and the rapid diversification and geographic spread of flowering plants.

Deriving temperature estimates from Southern Hemisphere leaves

The percentage of woody dicots with entire-margined leaves in a flora is known to be positively correlated with mean annual temperature (Leaf Margin Analysis — LMA) but this relationship is not globally uniform. In particular the floras of Australia and New Zealand have been regarded as displaying a different physiognomic relationship to climate than floras seen in the Northern Hemisphere. This difference is more marked in New Zealand where the LMA relationship appears entirely absent. Here we amass data for both Northern and Southern hemispheres using standard protocols and show that regional variations in the leaf margin–mean annual temperature relationship are real but become less significant when other characters are included. Even New Zealand falls into line and most of the mean annual temperature signal in New Zealand floras is encoded in non-margin features. We introduce a new CLAMP (Climate Leaf Analysis Multivariate Program) calibration dataset for the Southern Hemisphere, comprising leaf physiognomic data from Argentina, Bolivia, South Africa, Australia, New Zealand and other Pacific Islands that offers comparable precision for climate prediction to similar datasets derived from the Northern Hemisphere.

Large-scale dataset from China gives new insights into leaf margin–temperature relationships

Leaf margin analysis (LMA) is an important method of estimating paleotemperatures from fossil leaf floras or modern floras. Although some calibration has been carried out based upon large-scale studies of modern forests, most of this research has been in North America and Europe, with relatively little calibration work in East Asia. In the present study, we used species range maps of 3116 native dicot trees of China to derive synthetic local floras for each county from the Chinese humid region, and compared the percentage of untoothed leaf margined species with several temperature and precipitation related parameters. The results confirm the generally strong relationship between the proportion of species with untoothed leaf margins and climatic parameters within China. Leaf habit (deciduous vs. evergreen) does not strongly affect this relationship. The transfer function obtained from China, while not identical, is similar to those obtained from other regions, and is affected by regional restrictions, such as complex topography and relic taxa. As such it clarifies the potential range of error inherent in the LMA method as applied to paleoclimate reconstruction. It is possible, however, that with the close similarity of the modern Chinese tree floras to Neogene floras in the Northern Hemisphere, the present estimate offers a better transfer function for reconstructing the Neogene paleoclimate in various regions without extremely cold conditions across the Northern Hemisphere.

Paleoclimate estimates and fire ecology immediately prior to the end-Cretaceous mass extinction in the Frenchman Formation (66 Ma), Saskatchewan, Canada

The fossil-rich deposits of the uppermost Maastrichtian (66Ma) Frenchman Formation of southern Saskatchewan, Canada provide a detailed, continuous record of terrestrial ecosystem dynamics during the last half-million years leading up to the end-Cretaceous mass extinction. Paleoenvironmental interpretations for the Frenchman Formation are here refined by the first absolute paleoclimate estimates for the Late Cretaceous of Saskatchewan, and by the placement of these climate estimates within a North American context. Climate estimates were calculated using Leaf Margin Analysis and the Climate Leaf Analysis Multivariate Program (CLAMP), derived from two independent plant macrofossil assemblages collected from the Frenchman Formation. Climate parameter estimates indicate that the Maastrichtian climate of southern Saskatchewan was subtropical to warm-temperate, with mean annual temperatures between 12°C and 14°C, and with marked seasonality. These results are comparable with estimates derived from other late Campanian and Maastrichtian paleofloras in the Western Interior Basin, although small variations among coeval localities were noted or determined. Overall, the plant fossil assemblages from the two study localities support the paleoenvironmental interpretation of the Frenchman Formation as a swampy to lowland forest system with canopy-forming deciduous conifers and a diverse, angiosperm-dominated mid-canopy and understory. An unexpected, marked disparity in plant diversity was found between the two paleofloras, despite the plant assemblages returning similar paleoclimate parameter estimates. Abundant in situ inertinite (fossil charcoal) deposits were found in association with the less diverse paleofloral site, which contained only angiosperm fossils. Inertinite was absent from the deposits containing the more diverse paleoflora, which contained a different composition of angiosperm and gymnosperm fossils. Fire is known to be a prevalent feature of Late Cretaceous deposits worldwide, and modern angiosperm plants typically are the first to recover following fire disturbances. We suggest that the two Frenchman Formation paleofloras represent different stages of secondary ecological succession following a disturbance by fire. The identification of fire ecology in the fossil record may have important implications for understanding biodiversity patterns on small spatial and temporal scales immediately prior to the Cretaceous mass extinction.

New Paleogene paleoclimate analysis of western Washington using physiognomic characteristics from fossil leaves

The Chuckanut and Manastash formations were deposited in a lowland fluvial environment in western Washington during the Paleocene–Eocene. We provide a thorough paleotemperature analysis using the physiognomic characteristics from the fossil dicotyledonous leaves from these formations using two techniques, Leaf Margin Analysis (LMA) and Climate Leaf Analysis Multivariate Program (CLAMP). This work differs from previous analyses by 1) analyzing more localities and including the assessment of the never-before described Taneum Ridge Body and Manastash Main Body within the Manastash Formation and the Maple Falls Member of the Chuckanut Formation, and 2) using two different techniques to decipher mean annual temperatures through time. In this study, mean annual temperatures (MAT) were determined from 125 distinct morphotypes and are several degrees higher at each locality than previously reported. MAT values derived from LMA ranged from 17.0° to 28.8°C for the lowermost and 13.4° to 19.5°C for the uppermost Chuckanut Formation. The Manastash Formation had MATs ranging from 17.1°C to 29.1°C. Using CLAMP, paleotemperatures ranged from 15.3° to 19.4°C for the lowermost and 12.3° to 15.6°C for the uppermost Chuckanut Formation and 15.8 to 21.3°C for the Manastash Formation. These data are compared to other Eocene–Paleocene formations in the western US; the Chuckanut and Manastash formations record some of the warmest paleotemperatures in the Paleogene in the western US because of their low-elevation locations. These paleotemperatures may reflect the terrestrial signal of paleoclimate optima defined in marine rocks during the Paleocene–Eocene.

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

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.

Quantification of Calabrian climate in southern Primory'e, Far East of Russia — An integrative case study using multiple proxies

Early Pleistocene climate dynamics in the Russian Far East (southern Primory'e) is studied using multiple quantitative techniques on various palaeobotanical organ types. Climate data of the time were obtained from a total of 8 macrofloras (fruits and seeds, woods, and leaves) and 18 microfloras collected from a 10m thick, terrigenous succession exposed in the Pavlovskoe brown coal field. According to magnetostratigraphy, the studied section covers the last 200kyr of the Calabrian and comprises the early/late Pleistocene transition, a crucial time-span involving the transition from obliquity-forced cyclicity to the strong, eccentricity triggered glacial events. In this first integrative study on palaeoclimate of the Russian Far East, we employ Growth Ring Analysis, Multivariate Anatomical Analysis, Leaf Margin Analysis, Climate Leaf Analysis Multivariate Program, and Coexistence Approach on the different organs, partly originating from the same layer.The investigation documents the following important outcomes: 1) Climate data obtained from the various methods are proven to be largely consistent. 2) The late Calabrian of the southern Primory'e was characterized by overall cooling and drying. Our climate record displays 2 small scale cycles. Warm peaks (at 19.4–19.8 and 14.0–14.8m) are tentatively correlated to the global isotope stages MIS 25 and MIS 21, respectively. 3) In the warm phases, the Calabrian climate of southern Primory'e was significantly warmer and wetter when compared to the present, especially regarding the cold season while in cold phases, climate was similar to modern or event slightly cooler. 4) As of today, Early Pleistocene climate of southern Primory'e was warmer and wetter than neighboring areas of the south RFE. 5) The effect of the East Asian Monsoon Systems on the climate of the southern Primory'e was less pronounced compared to the present.

Foliar physiognomic climate estimates for the Late Cretaceous (Cenomanian–Turonian) Lark Quarry fossil flora, central-western Queensland, Australia

Although there is a broad knowledge of Cretaceous climate on a global scale, quantitative climate estimates for terrestrial localities are limited. One source of terrestrial palaeoproxies is foliar physiognomy. The use of foliar physiognomy to explore Cretaceous assemblages has been limited, and some of its potential sources of error have not been fully explored. Although museum collections house a wealth of material, collection bias toward particular taxa or preservation qualities of specimens further magnifies existing taphonomic bias to cold temperatures. As a result, specific collection for foliar physiognomy can be necessary. Here, we conduct three foliar physiognomic analyses on the early Late Cretaceous Lark Quarry flora and assess the results in the context of other proxies from the same formation. Our results suggest that the climate at the Cenomanian–Turonian boundary in central western Queensland was warm and had high precipitation (leaf-area analysis: 1321 mm + 413 mm – 315 mm mean annual precipitation; leaf-margin analysis: 16.4°C mean annual temperature, 5.3°C binomial sample error; climate leaf-analysis multivariate program: 16 ± 2°C for mean annual temperature, 9-month growth season, 1073 ± 483 mm growth-season precipitation). Our analysis also gave higher mean annual temperature estimates than did a previous analysis by climate leaf-analysis multivariate program, based on museum collections for the Winton Formation.

Paleoclimatic estimation reveals a weak winter monsoon in southwestern China during the late Miocene: Evidence from plant macrofossils

The late Miocene Xianfeng flora of Yunnan Province, southwestern China, was chosen to reconstruct the paleoclimate and the intensity of the Asian monsoon. Three available quantitative climate reconstruction methods from fossil plants, i.e. Leaf Margin Analysis (LMA), the Climate Leaf Analysis Multivariate Program (CLAMP), and the Coexistence Approach (CA) were used in this study. MATs (mean annual temperatures) resulting from these three approaches (i.e., LMA: 17.2±2.38°C; CLAMP: 15.43±1.25°C; CA: 17.2–21.7°C) appear to have been higher than the present (14.9°C), suggesting a much warmer climate in the late Miocene. Both the growing season precipitation (GSP) from CLAMP (1908.7±217.7mm) and mean annual precipitation (MAP) from CA (1206.0–1613.0mm) estimates are higher than modern values (1003.2mm (GSP) and 1038mm (MAP) respectively) indicating a more humid climate during the late Miocene. By comparing these with climates reconstructed from neighboring late Miocene floras, we conclude that the general late Miocene climate appears warmer and more humid than present conditions in southwestern China. Furthermore, the evident differences in estimated monthly temperatures between the summer and winter, and precipitations between the humid and dry seasons indicate the existence of seasonality, though not as strong as that of today. Difference in precipitation of dry season indicates a marked strengthening in the winter monsoon since the late Miocene. A new monsoon intensity index has also been defined based on precipitation seasonality to investigate the intensity of the Asian monsoon.

Environmental analysis of the mid-latitudinal European Eocene sites of plant macrofossils and their possible analogues in East Asia

Previously known Eocene floras of mid-latitudinal Europe are analysed using statistical methodologies in order to obtain more reliable palaeoclimatological signals to detect possible climatic fluctuations during this time interval. Only macrofossil assemblages have been taken into account and subjected to the statistical evaluation called the Integrated Plant Record (IPR) vegetation analysis, which is based mostly on percentages of various components. Additional palaeoclimatic approaches were employed, namely the Coexistence Approach, based on autecology of the nearest living relatives, and the physiognomic methods of the Leaf Margin Analysis and Climate Leaf Analysis Multivariate Program (CLAMP). The same statistical approaches have been applied to analogous living vegetation of China and Japan for comparative purposes. Additionally, an update of objective statistical tools for the selection of the best-suited modern vegetation CLAMP dataset from 144 site (Physg3br/GRIDMet3br), 173 (Physg3ar/GRIDMet3ar) and 189 (PhysgAsia1/GRIDMetAsia1) extant biotopes is proposed including its “copy & paste” Excel application.