Alexis Licht

Centre Européen de Recherche et d’Enseignement des Géosciences de l’Environnement, French National Centre for Scientific Research | CEREGE · Climate

The strong present-day Asian monsoons are thought to have originated between 25 and 22 million years (Myr) ago, driven by Tibetan–Himalayan uplift. However, the existence of older Asian monsoons and their response to enhanced greenhouse conditions such as those in the Eocene period (55–34 Myr ago) are unknown because of the paucity of well-dated re...

The loess and paleosol sequences of the Chinese Loess Plateau are composed of Quaternary dust, the origin of which has been the subject of considerable debate. Some recent U-Pb geochronological studies of eolian zircons have proposed the existence of two major wind pathways: from the north and northwest, through the Badan Jaran, Tengger, and Mu Us...

The onset of modern central Asian atmospheric circulation is traditionally linked to the interplay of surface uplift of the Mongolian and Tibetan-Himalayan orogens, retreat of the Paratethys sea from central Asia and Cenozoic global cooling. Although the role of these players has not yet been unravelled, the vast dust deposits of central China supp...

The Apt Basin, sub-basin of the wider Manosque Basin of southeastern France, contains deposits of Eocene-Oligocene lake systems that were part of a broader network of evaporative lakes and lagoons spread across the European Cenozoic rift system. The onset and mechanisms of subsidence in the rift system, the interconnectivity of these lakes, and the...

作为自晚始新世以来劳亚大陆和冈瓦纳大陆之间植物扩散的交汇点，缅甸中部盆地出土了丰富多样的化石花粉。本研究报道了来自缅甸中部盆地上始新统Yaw 组无患子科（Sapindaceae）植物的一种花粉化石新属和新种——格林氏粉属（Grimipollis）和缅甸格林氏粉（Grimmipollis burmanica）。利用层次聚类分析和花粉图谱揭示其花粉纹饰与其他 类似属的相似性和古生态。Grimmipollis 的花粉粒具有副合孔（parasyncolporate）的孔口，两侧有顶孔区（apocolpial field），孔沟边缘（margines）明显，副合孔的孔沟沿线有弧形、结节状和绳状的中孔脊（mesocolpial ridges），以及显著的疣状或槽状顶孔区（apocolpia）。这些特征将...

The mechanisms and pace of orbital forcing on precipitation in inland Asia during the Cenozoic remain poorly understood. Many previous studies using magnetic proxies for precipitation have shown a consistent signal of long eccentricity (405 kyr) in hydrological records of central China that are younger than ca. 11 Ma. Most studies suggest that vari...

Sedimentary provenance is a powerful tool for reconstructing convergent margin evolution. However, single mineral approaches, like detrital zircon, have struggled to track sediment input from mafic and metamorphic sources. Detrital rutile complements detrital zircon datasets by offering a path forward in sedimentary provenance reconstructions where...

Embrithopoda is an extinct clade of herbivorous placental mammals belonging to the afrotherian subclade Paenungulata. Early in their evolutionary history, embrithopods colonized the insular terrane of Balkanatolia, presumably via dispersal across the Tethyan marine barrier that separated Africa from Eurasia during the early Cenozoic. Here we report...

Sahara sands have been proposed to result from the extensive and repetitive recycling of much older sedimentary rocks-a necessary mechanism to explain their petrographic maturity and the similarity of their detrital zircon populations at continental scale. Where and how this recycling occurs today remain poorly understood. This study investigates t...

The dry continental interior of Asia has remained arid throughout most of its geological history, yet the future of this unique ecosystem remains unclear. Here we use palynological and isotopic records to track vegetation and moisture throughout the warm early Eocene (57 to 44 million years ago) as an analogue for extreme atmospheric CO2 scenarios....

Premise: The rise of angiosperm‐dominated tropical rainforests has been proposed to have occurred shortly after the Cretaceous–Paleogene transition. Paleocene fossil wood assemblages are rare yet provide important data for understanding these forests and whether their wood anatomical features can be used to document the changes that occurred during...

The Eocene-Oligocene transition marks a period of dramatic global climatic change correlated with pronounced mammalian faunal change. Fossil evidence is indispensable for studying the distribution of taxa through time, and determining how abiotic parameters shaped ancient biodiversity. Here we report ruminant artiodactyls and a new anthropoid prima...

When the modern features of large-scale Asian monsoonal circulation were set-up is poorly constrained and pre-Neogene monsoonal archives are rare. This study investigates the temporal evolution of neritic carbonates in the proto-South China Sea to reconstruct East Asian monsoonal currents and winds during the middle to late Paleogene. Analysis of t...

Two new specimens of the anatoliadelphyid metatherian Orhaniyeia nauta are described from the middle Eocene Uzunçarşıdere Formation in the Orhaniye Basin, north-central Turkey. These specimens augment our knowledge of the dentition of this taxon, revealing that P3 and p3 of Orhaniyeia resemble those of its sister taxon Anatoliadelphys in being enla...

Sedimentary provenance is a powerful tool for reconstructing convergent margin evolution. Yet single mineral approaches, like detrital zircon, have struggled to track sediment input from mafic and metamorphic sources. Sediment input from these lithologies is especially critical for reconstructing orogenic settings dominated by terrane accretion, op...

Acid extraction methods have been used in the last half century to selectively extract the CO2 produced from different carbonate minerals in mixed samples. However, these methods are often time-consuming and labor intensive. Their application to clumped isotope (Δ47) analysis has not been demonstrated. We propose here an acid extraction method with...

The Asian monsoons are triggered by complex interactions between the atmosphere, Asian and African orography, and the surrounding oceans, resulting in highly seasonal climate and specific regional features. It was thought that the Asian monsoon was established during the Neogene, but recent evidence for monsoon-like precipitation seasonality occurr...

Deciphering dust outbreak frequency in inland Asia during the late Cenozoic is important for predicting future hydroclimate in the arid parts of China. Here, we present an eolian sedimentary sequence in the southern Junggar Basin over the past 3.5 Ma, Northwestern China. Our data provide a minimum age of 3.5 Ma for the Gurbantunggut Desert. Rb/Sr r...

The number of subduction zones that facilitated the northward translation of the Anatolide-Tauride continental terrane derived from Gondwana to the southern margin of Eurasia at the longitude of western Turkey is debated. We hypothesized that if two north dipping subduction zones facilitated incipient collision in western Turkey, a late Cretaceous...

As a crossroads for plant dispersal between Laurasia and Gondwana since at least the late Eocene, the Central Myanmar Basins have yielded rich and diverse fossil pollen . Here we report Grimmipollis burmanica, a new genus and species in the soapberry family (Sapindaceae) from the upper Eocene Yaw Formation in the Central Myanmar Basins. We also inv...

The Burma Terrane has yielded some of the earliest pieces of evidence for monsoonal rainfall in the Bay of Bengal. However, Burmese ecosystems and their potential monsoonal imprint remain poorly studied. This study focuses on the late Eocene Yaw Formation (23° N) in central Myanmar, which was located near the equator (c. 5° N) during the Eocene. We...

The mechanisms and pace of orbital forcing on precipitation in inland Asia during the Cenozoic remain poorly understood. Many previous studies have shown a consistent signal of long eccentricity (405 kyr) on precipitation records of central China that are younger than ~11 Ma. These studies suggest that variations of rainfall amount were controlled...

Aeshna caseneuvensis sp. nov., the second oldest representative of the genus Aeshna, is described and figured from the lowermost Oligocene of Luberon in southeastern France. The oldest described species in this genus is from the uppermost Eocene of Colorado in USA. Their occurrence in very distant areas in an interval of time of less of five millio...

Mio-Pliocene sedimentary archives of the East Asian summer monsoon (EASM) in NE Tibet record a monotonic response to orbital forcing, dominated by eccentricity. By contrast, Pleistocene archives display a more stochastic response that varies regionally and temporally. When and why this response changed is poorly understood. Here, we present a new h...

The Leech River Shear Zone (LRSZ) on southern Vancouver Island separates the metasedimentary schists of the Leech River Complex (LRC) from the accreted oceanic plateau of the Siletz‐Crescent terrane. The juxtaposition of these rock units suggests a possible origin as a subduction plate boundary but tectonic context of the LRSZ has yet to be fully e...

Some of the earliest pieces of evidence for monsoonal activity in the Bengal Bay come from the middle and Upper Eocene sedimentary series of Myanmar. Recent paleogeographic reconstructions have yet relocated Myanmar close to the equator during the Eocene, which questions the relevance of Burmese material to study past South Asian monsoonal activity...

The Cenozoic strata of the Xining Basin, NE Tibet, have provided crucial records for understanding the tectonic and paleo‐environmental evolution of the region. Yet, the age for the lower part of the sedimentary stratigraphy and consequently the early tectonic evolution of the basin remain debated. Here, we present the litho‐ and magnetostratigraph...

The palaeobotanical record of Myanmar (Burma) is poorly documented despite its importance for understanding the evolution of Asian monsoonal ecosystems through time. Here, we describe 20 taxa of fossil wood from 30 silicified specimens collected in the upper lower to lowermost middle Miocene Natma Formation, central Myanmar. These fossils share aff...

Pedogenic carbonate is widespread at mid latitudes where warm and dry conditions favor soil carbonate growth from spring to fall. The mechanisms and timing of pedogenic carbonate formation are more ambiguous in the tropical domain, where long periods of soil water saturation and high soil respiration enhance calcite dissolution. This paper provides...

The drivers of the evolution of the South Asian Monsoon remain widely debated. An intensification of monsoonal rainfall recorded in terrestrial and marine sediment archives from the earliest Miocene (23–20 million years ago (Ma)) is generally attributed to Himalayan uplift. However, Indian Ocean palaeorecords place the onset of a strong monsoon aro...

Collision between the Pontides and Anatolide-Tauride Block along the İzmir-Ankara-Erzincan suture in Anatolia has been variously estimated from the Late Cretaceous to Eocene. It remains unclear whether this age range results from a protracted, multi-phase collision or differences between proxies of collision age and/or along strike diachroneity. He...

The Ayeyarwady River flows for 2170 km to the Andaman Sea from above 3000 m altitude in the Eastern Himalayan Syntaxis. The Ayeyarwady is one of the largest river systems in the world in terms of water and sediment discharge. The Ayeyarwady floodplains have supported agriculture through the Neolithic and successive urban civilizations since the lat...

At the junction of greenhouse and icehouse climate states, the Eocene–Oligocene Transition (EOT) is a key moment in Cenozoic climate history. While it is associated with severe extinctions and biodiversity turnovers on land, the role of terrestrial climate evolution remains poorly resolved, especially the associated changes in seasonality. Some pal...

The Andaman and Nicobar ophiolites, in the forearc of the western Sunda subduction zone, underwent enigmatic, rapid Cenozoic vertical motions: shallow-water sediments with abundant arc debris characterize the middle Paleocene–middle Eocene and are under- and overlain by significantly deeper sediments. Recent paleomagnetic results revealed a near-eq...

The Grande Coupure corresponds to a major episode of faunal turnover in western Europe around the Eocene-Oligocene boundary that is generally attributed to the influx of multiple clades of Asian mammals. However, Asian mammal clades begin to appear in the fossil record of southeastern Europe during the middle Eocene, 5–10 million years prior to the...

Across the Miocene–Pliocene boundary (MPB; 5.3 million years ago, Ma), late Miocene cooling gave way to the early-to-middle Pliocene Warm Period. This transition, across which atmospheric CO 2 concentrations increased to levels similar to present, holds potential for deciphering regional climate responses in Asia—currently home to more than half of...

Recent studies suggest increasing sensitivity to orbital variations across the Eocene-Oligocene greenhouse to icehouse climate transition. However, climate simulations and paleoenvironmental studies mostly provide snapshots of the past climate, therefore overlooking the role of this short-term variability in driving major environmental changes and...

Palm and palm-like (PPL) taxa have been widely reported at low-mid latitudes in Paleogene pollen assemblages. Yet their occurrence in the Paleogene of Myanmar remains poorly documented. Here we investigate the morphology of PPL pollen along a middle to upper Eocene sedimentary sequence in the Central Myanmar Basin and discuss their nearest living r...

A micrograph (a swamp fern spore 𝙂𝙚𝙢𝙢𝙖𝙩𝙤𝙨𝙥𝙤𝙧𝙞𝙨 𝙜𝙚𝙢𝙢𝙖𝙩𝙤𝙞𝙙𝙚𝙨 with affinity to 𝘾𝙮𝙘𝙡𝙤𝙥𝙝𝙤𝙧𝙪𝙨) in our paper ("𝗔𝘁 𝗮 𝗰𝗿𝗼𝘀𝘀𝗿𝗼𝗮𝗱𝘀: 𝗧𝗵𝗲 𝗹𝗮𝘁𝗲 𝗘𝗼𝗰𝗲𝗻𝗲 𝗳𝗹𝗼𝗿𝗮 𝗼𝗳 𝗰𝗲𝗻𝘁𝗿𝗮𝗹 𝗠𝘆𝗮𝗻𝗺𝗮𝗿 𝗼𝘄𝗲𝘀 𝗶𝘁𝘀 𝗰𝗼𝗺𝗽𝗼𝘀𝗶𝘁𝗶𝗼𝗻 𝘁𝗼 𝗽𝗹𝗮𝘁𝗲 𝗰𝗼𝗹𝗹𝗶𝘀𝗶𝗼𝗻 𝗮𝗻𝗱 𝘁𝗿𝗼𝗽𝗶𝗰𝗮𝗹 𝗰𝗹𝗶𝗺𝗮𝘁𝗲", Huang et al. (2021), https://doi.org/10.1016/j.revpalbo.2021.104441) was selected as the cover image on the cover of volume 2...

Myanmar was shaped by the India–Asia collision, fusion of the Burma Terrane (BT) with Asia, and mountain building. Throughout this process new elevational gradients and habitats were formed, which affected the regional climate, but also forged new dispersal routes into Asia and India. In spite of its importance, the vegetation history of Myanmar is...

At the junction of greenhouse and icehouse climate phases, the Eocene-Oligocene Transition (EOT) is a key moment in the history of the Cenozoic climate. Yet, while it is associated with severe extinctions and biodiversity turnovers, terrestrial climate evolution remains poorly resolved. Paleobotanical and geochemical continental records suggest a m...

The geology of Myanmar was shaped by the India-Asia collision, fusion of the Burma Terrane (BT) with Asia, and mountain building. Throughout this process new elevational gradients and habitats were formed, which affected the regional climate and biodiversity, but also forged new dispersal routes into Asia and India. In spite of its importance, the...

High burial temperature and a lack of material for traditional thermal proxies significantly impede the understanding of the thermal history of carbonate stratigraphic sequences in deep time. Carbonate clumped isotope thermometry interpreted through models of solid‐state isotopic reordering and in situ U‐Pb dating provides a new methodology for rec...

Asian mineral dust has been studied extensively for its role in affecting regional‐to global‐scale climate and for its deposits, which enable reconstructing Asian atmospheric circulation in the past. However, the timing and origin of the dust deposits remain debated. Numerous loess records have been reported across the Asian continent with ages var...

Paleogeographic maps are essential tools for understanding Earth system dynamics. They provide boundary conditions for climate and geodynamic modelling, for analysing surface processes and biotic interactions. However, the temporal and spatial distribution of key features such as seaways and mountain belts that govern climate changes and biotic int...

Recognition of terrestrial dust in geological records is essential for reconstructing paleoenvironments and quantifying dust fluxes in the past. However, in contrast to eolian sands, silt-sized dust is difficult to recognize in pre-Quaternary records due to a lack of macroscopic features indicating eolian transport and mixing with alluvial sediment...

The Olympic Peninsula is the uplifted portion of the Cascadia accretionary wedge and forms the core of a 200 km scale oroclinal bend on the west coast of Washington State. The accretionary wedge started forming 45 million years ago following the accretion of the Siletzia igneous province along the Cascadia subduction margin. Low-temperature thermoc...

The Burma Terrane (Myanmar) played an important role in the India‐Asia collision and moved over 2,000 km northward on the Indian Plate during the Cenozoic, before colliding with the Asian margin. However, the timing of this collision and its correlation to regional uplift phases, sedimentary provenance, and basin development remain poorly constrain...

The first major build-up of Antarctic glaciation occurred in two consecutive stages across the Eocene–Oligocene transition (EOT): the EOT-1 cooling event at ~34.1–33.9 Ma and the Oi-1 glaciation event at ~33.8–33.6 Ma. Detailed orbital-scale terrestrial environmental responses to these events remain poorly known. Here we present magnetic and geoche...

The origins and development of the arid and highly seasonal steppe-desert biome in Central Asia, the largest of its kind in the world, remain largely unconstrained by existing records. It is unclear how Cenozoic climatic, geological, and biological forces, acting at diverse spatial and temporal scales, shaped Central Asian ecosystems through time....

The Burma Terrane (Myanmar) played an important role in the India‐Asia collision and moved over 2000 km northward on the Indian Plate during the Cenozoic, before colliding with the Asian margin. However, the timing of this collision and its correlation to regional uplift phases, sedimentary provenance and basin development, remain poorly constraine...