Multiple Phases of Mountain Building on the Northern Tibetan Margin

Abstract The history of mountain building along the northern Tibetan margin since its initiation remains unclear. The exhumation evolutionary history of the Kunlun Belt, the first-order mountain range of northern Tibet, is resolved by using 40Ar/39Ar thermochronological analyses of Paleozoic and Mesozoic granitic intrusions. Four rapid exhumation events are identified from analyses employing multiple domain diffusion theories in the Carboniferous (~355-295 Ma), Triassic (~245-205 Ma), Cretaceous (~120-95 Ma), and Eocene (~40-35 Ma). The cooling rates and the therefrom deduced denudation rates are estimated for these stages. The events are interpreted to reflect the closure of the Prototethys Ocean in the early Paleozoic, closure of the Paleotethys ocean in the late Paleozoic, far-field effects from the closure of the Mesotethys Ocean, and far-field effects from the Paleogene convergence of India and Eurasia, respectively. These events collectively built up the present northern Tibetan margin.

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Southward expanding plate coupling due to variation in sediment subduction as a cause of Andean growth

Nature Communications ◽

10.1038/s41467-021-27518-8 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Jiashun Hu ◽

Lijun Liu ◽

Michael Gurnis

Keyword(s):

Sediment Transport ◽

Three Dimensional ◽

Mountain Building ◽

Crustal Shortening ◽

First Order ◽

The Andes ◽

Tectonic Processes ◽

History Of ◽

Plate Coupling ◽

Trench Sediments

AbstractGrowth of the Andes has been attributed to Cenozoic subduction. Although climatic and tectonic processes have been proposed to be first-order mechanisms, their interaction and respective contributions remain largely unclear. Here, we apply three-dimensional, fully-dynamic subduction models to investigate the effect of trench-axial sediment transport and subduction on Andean growth, a mechanism that involves both climatic and tectonic processes. We find that the thickness of trench-fill sediments, a proxy of plate coupling (with less sediments causing stronger coupling), exerts an important influence on the pattern of crustal shortening along the Andes. The southward migrating Juan Fernandez Ridge acts as a barrier to the northward flowing trench sediments, thus expanding the zone of plate coupling southward through time. Consequently, the predicted history of Andean shortening is consistent with observations. Southward expanding crustal shortening matches the kinematic history of inferred compression. These results demonstrate the importance of climate-tectonic interaction on mountain building.

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Early exhumation of the Frontal Cordillera (southern Central Andes at ~33.5°S) and implications for Andean mountain-building

10.5194/egusphere-egu2020-3346 ◽

2020 ◽

Author(s):

Robin Lacassin ◽

Magali Riesner ◽

Martine Simoes ◽

Tania Habel ◽

Audrey Margirier ◽

...

Keyword(s):

Central Andes ◽

Crustal Thickening ◽

Mountain Range ◽

Mountain Building ◽

Ongoing Debate ◽

First Order ◽

The Andes ◽

Minimum Age ◽

Southern Central ◽

Basement Structures

The Andes are the modern active example of a Cordilleran-type orogen, with mountain-building&#8232; and crustal thickening within the upper plate of a subduction zone. Despite numerous studies of&#8232; this emblematic mountain range, several primary traits of this orogeny remain unresolved or poorly documented. The timing of uplift and deformation of the Frontal Cordillera basement culmination of&#8232; the Southern Central Andes is such an example, even though this structural unit appears as a first-order topographic and geological feature. Constraining this timing and in particular the onset of uplift is a key point in the ongoing debate about the initial vergence of the crustal-scale thrusts at the start of the Cenozoic Andean orogeny. To solve for this, new apatite and zircon (U-Th)/He ages from granitoids of the Frontal Cordillera at ~33.5&#176;S are provided here. These data, interpreted as an age-elevation thermochronological profile, imply continuous exhumation initiating well before ~12&#8211;14 Ma, and at most by ~22 Ma when considering the youngest zircon grain from the lowermost sample (Riesner et al. 2019). The inverse modeling of the thermochronological data using QTQt software confirms these conclusions and point to a continuous cooling rate since onset of cooling. The minimum age of exhumation onset is then refined to ~20 Ma by combining these results with data on sedimentary provenance from the nearby basins. Such continuous exhumation since ~20 Ma needs to have been sustained by tectonic uplift on an underlying crustal-scale thrust ramp. Such early exhumation and associated uplift of the Frontal Cordillera question the classically proposed east-vergent models of the Andes at this latitude. Additionally, this study provides further support to recent views on Andean mountain-building proposing that the Andes-Altiplano orogenic system grew firstly over west-vergent basement structures before shifting to dominantly east-vergent thrusts.&#160; Riesner M. et al. 2019, Scientific Reports, DOI: 10.1038/s41598-019-44320-1

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Mountain building and species radiations in the Andes: a reconstruction of surface uplift and species diversification since the Late Cretaceous from a compilation of paleo-elevation estimates, thermochronology, and phylogenetic data.

10.5194/egusphere-egu2020-7941 ◽

2020 ◽

Author(s):

Lydian Boschman ◽

Mauricio Bermúdez ◽

Fabien Condamine

Keyword(s):

Low Temperature ◽

Mountain Range ◽

The South ◽

Mountain Building ◽

Species Diversification ◽

Origin And Evolution ◽

Continental Scale ◽

Surface Uplift ◽

The Andes ◽

History Of

The Andes are the longest continental mountain range on Earth, stretching from tropical Colombia and Venezuela in the north to temperate to sub-polar Patagonia in the south along the western margin of the South American continent. Biological diversity is extraordinarily high, especially in the northern tropical Andes, which are considered to be the richest biodiversity hotspot in the world. The Andes are relatively young; a large part of the modern topography is the result of surface uplift that occurred during and since the Miocene. However, large differences exist in the timing of shortening, exhumation, and surface uplift between the northern, central, and southern Andes, as well as between the various parallel Cordilleras. Mountain building directly links to climate dynamics, the development of drainage patterns, and the evolution of biomes and biodiversity. Therefore, determining the timing of surface uplift for each of the different Andean regions is of crucial importance for our understanding of continental-scale moisture transport and atmospheric circulation, the origin and evolution of the Amazon River and Rainforest, and ultimately, the origin and evolution of species in South America.Determining surface elevations through geological time is not straightforward because the geological record does not contain a direct measure of topography. Commonly used methods to indirectly estimate paleo-elevation include low temperature thermochronology, palynology/paleobotany, the identification and dating of paleosurfaces, and analyzing the stratigraphic record of foreland basins that quantitatively record the topographic and erosional history of an adjacent mountain range. Additionally, paleo-elevation can be estimated more directly by stable isotope paleo-altimetry: atmospheric &#948;18O and &#948;D vary with elevation as precipitation from ascending air parcels along an orographic barrier removes the heavy isotopes. The &#948;18O and &#948;D values in authigenic/pedogenic materials (paleosols or lakes), biogenic archives (e.g. fossil teeth), volcanic glass, or organic biomarkers (e.g. leaf-wax n-alkanes preserved in soils or sediments) may thus record paleo-elevation.In this study, we present a compilation of (direct and indirect) estimates of paleo-elevation of the Andes. We generate a reconstruction of surface uplift, per latitudinal sector of the Andes and per Cordillera or range, containing elevation values per 1x1 degree cell and per Myr. We discuss the areas and/or times where this reconstruction is uncertain as a result of either a lack of data, or a discrepancy between different data sets. Next, we present a compilation of low temperature thermochronology data, and compare the paleo-elevation history of the Andes with its exhumation history. We analyze spatial and temporal variations in erosion rates during Andean mountain building. Last, we use the paleo-elevation reconstruction to analyze the role of Andean mountain building in the rates of species diversification for hummingbirds (clade of Brilliants and Coquettes), iguanians (Liolaemus), tree frogs (two families), and flowering plants (centropogonids and orchids). We use a model&#8208;testing approach that compares various diversification scenarios including a series of biologically realistic models to estimate speciation and extinction rates using a phylogeny, while assessing the relationship between diversification and environmental variables.

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Molecular phylogenetics and evolutionary history of the endemic land snail genus Everettia in northern Borneo

PeerJ ◽

10.7717/peerj.9416 ◽

2020 ◽

Vol 8 ◽

pp. e9416 ◽

Cited By ~ 1

Author(s):

Thor-Seng Liew ◽

Mohammad Effendi Marzuki ◽

Menno Schilthuizen ◽

Yansen Chen ◽

Jaap J. Vermeulen ◽

...

Keyword(s):

Evolutionary History ◽

Molecular Phylogenetics ◽

Divergence Time ◽

Distribution Patterns ◽

Land Snail ◽

High Elevation ◽

Mountain Range ◽

Climatic Fluctuations ◽

Species Diversification ◽

History Of

Borneo has gone through dramatic changes in geology and topography from the early Eocene until the early Pliocene and experienced climatic cycling during the Pleistocene. However, how these changes have shaped the present-day patterns of high diversity and complex distribution are still poorly understood. In this study, we use integrative approaches by estimating phylogenetic relationships, divergence time, and current and past niche suitability for the Bornean endemic land snail genus Everettia to provide additional insight into the evolutionary history of this genus in northern Borneo in the light of the geological vicariance events and climatic fluctuations in the Pleistocene. Our results show that northern Borneo Everettia species belong to two deeply divergent lineages: one contains the species that inhabit high elevation at the central mountain range, while the other contains lowland species. Species diversification in these lineages has taken place before the Pliocene. Climate changes during the Pleistocene did not play a significant role in species diversification but could have shaped contemporary species distribution patterns. Our results also show that the species-rich highland habitats have acted as interglacial refugia for highland species. This study of a relatively sedentary invertebrate supports and enhances the growing understanding of the evolutionary history of Borneo. Species diversification in Everettia is caused by geological vicariance events between the early Miocene and the Pliocene, and the distribution patterns were subsequently determined by climatic fluctuations in the Pleistocene.

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Elaborating the role of reflection and individual differences in the study of folk-economic beliefs

Behavioral and Brain Sciences ◽

10.1017/s0140525x18000274 ◽

2018 ◽

Vol 41 ◽

Author(s):

Kevin Arceneaux

Keyword(s):

Decision Making ◽

Individual Differences ◽

Cognitive Processes ◽

Evolutionary History ◽

Behavioral Responses ◽

History Of ◽

Economic Beliefs

AbstractIntuitions guide decision-making, and looking to the evolutionary history of humans illuminates why some behavioral responses are more intuitive than others. Yet a place remains for cognitive processes to second-guess intuitive responses – that is, to be reflective – and individual differences abound in automatic, intuitive processing as well.

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