Large-scale hydrological change drove the late Miocene C4 plant expansion in the Himalayan foreland and Arabian Peninsula

AbstractTurbulent mixing in the planetary boundary layer (PBL) governs the vertical exchange of heat, moisture, momentum, trace gases, and aerosols in the surface–atmosphere interface. The PBL height (PBLH) represents the maximum height of the free atmosphere that is directly influenced by Earth’s surface. This study uses a multidata synthesis approach from an ensemble of multiple global datasets of radiosonde observations, reanalysis products, and climate model simulations to examine the spatial patterns of long-term PBLH trends over land between 60°S and 60°N for the period 1979–2019. By considering both the sign and statistical significance of trends, we identify large-scale regions where the change signal is robust and consistent to increase our confidence in the obtained results. Despite differences in the magnitude and sign of PBLH trends over many areas, all datasets reveal a consensus on increasing PBLH over the enormous and very dry Sahara Desert and Arabian Peninsula (SDAP) and declining PBLH in India. At the global scale, the changes in PBLH are significantly correlated positively with the changes in surface heating and negatively with the changes in surface moisture, consistent with theory and previous findings in the literature. The rising PBLH is in good agreement with increasing sensible heat and surface temperature and decreasing relative humidity over the SDAP associated with desert amplification, while the declining PBLH resonates well with increasing relative humidity and latent heat and decreasing sensible heat and surface warming in India. The PBLH changes agree with radiosonde soundings over the SDAP but cannot be validated over India due to lack of good-quality radiosonde observations.

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Increased seasonality and aridity drove the C4 plant expansion in Central Asia since the Miocene–Pliocene boundary

Earth and Planetary Science Letters ◽

10.1016/j.epsl.2018.08.056 ◽

2018 ◽

Vol 502 ◽

pp. 74-83 ◽

Cited By ~ 8

Author(s):

Xingyan Shen ◽

Shiming Wan ◽

Christophe Colin ◽

Ryuji Tada ◽

Xuefa Shi ◽

...

Keyword(s):

Central Asia ◽

C4 Plant ◽

Plant Expansion

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Melt equilibration depths as sensors of lithospheric thickness during Eurasia-Arabia collision and the uplift of the Anatolian Plateau

Geology ◽

10.1130/g46420.1 ◽

2019 ◽

Vol 47 (10) ◽

pp. 943-947 ◽

Cited By ~ 3

Author(s):

M.R. Reid ◽

J.R. Delph ◽

M.A. Cosca ◽

W.K. Schleiffarth ◽

G. Gençalioğlu Kuşcu

Keyword(s):

Late Miocene ◽

Large Scale ◽

Middle Miocene ◽

Volcanic Rocks ◽

Suture Zone ◽

Arabian Plate ◽

Seismic Structure ◽

Eurasian Plate ◽

Lithospheric Thickness ◽

Anatolian Plateau

Abstract A co-investigation of mantle melting conditions and seismic structure revealed an evolutionary record of mantle dynamics accompanying the transition from subduction to collision along the Africa-Eurasia margin and the >1 km uplift of the Anatolian Plateau. New 40Ar/39Ar dates of volcanic rocks from the Eastern Taurides (southeast Turkey) considerably expand the known spatial extent of Miocene-aged mafic volcanism following a magmatic lull over much of Anatolia that ended at ca. 20 Ma. Mantle equilibration depths for these chemically diverse basalts are interpreted to indicate that early to middle Miocene lithospheric thickness in the region varied from ∼50 km or less near the Bitlis suture zone to ∼80 km near the Inner Tauride suture zone. This southward-tapering lithospheric base could be a vestige of the former interface between the subducted (and now detached) portion of the Arabian plate and the overriding Eurasian plate, and/or a reflection of mantle weakening associated with greater mantle hydration trenchward prior to collision. Asthenospheric upwelling driven by slab tearing and foundering along this former interface, possibly accompanied by convective removal of the lithosphere, could have led to renewed volcanic activity after 20 Ma. Melt equilibration depths for late Miocene and Pliocene basalts together with seismic imaging of the present lithosphere indicate that relatively invariant lithospheric thicknesses of 60–70 km have persisted since the middle Miocene. Thus, no evidence is found for large-scale (tens of kilometers) Miocene delamination of the lower lithosphere from the overriding plate, which has been proposed elsewhere to account for late Miocene and younger uplift of Anatolia.

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Regional Climatic Features of the Arabian Peninsula

Atmosphere ◽

10.3390/atmos10040220 ◽

2019 ◽

Vol 10 (4) ◽

pp. 220 ◽

Cited By ~ 10

Author(s):

Patlakas ◽

Stathopoulos ◽

Flocas ◽

Kalogeri ◽

Kallos

Keyword(s):

Large Scale ◽

Arabian Peninsula ◽

Regional Climate ◽

Atmospheric Model ◽

Temporal Variations ◽

Spatial And Temporal Variations ◽

Spatial Distance ◽

Temperature Extremes ◽

Mean Temperature ◽

Maximum Temperatures

The climate of the Arabian Peninsula is characterized by significant spatial and temporal variations, due to its complex topography and the large-scale atmospheric circulation. Furthermore, the role of dust in the formation of regional climate is considered to be crucial. In this work, the regional climatology for the Arabian Peninsula has been studied by employing a high resolution state of the art atmospheric model that included sophisticated physical parameterization schemes and online treatment of natural aerosol particles. The simulations covered a 30-year period (1986–2015) with a temporal resolution of 3 h and a spatial distance of 9 km. The main focus was given to the spatial and temporal variations of mean temperature and temperature extremes, wind speed and direction, and relative humidity. The results were evaluated using in situ measurements indicating a good agreement. An examination of possible climatic changes during the present climate was also performed through a comprehensive analysis of the trends of mean temperature and temperature extremes. The statistical significant trend values were overall positive and increased over the northwestern parts of the examined area. Similar spatial distributions were found for the daily minimum and maximum temperatures. Higher positive values emerged for the daily maxima.

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Carnivora from the Baynunah Formation

10.31233/osf.io/pa8cf ◽

2021 ◽

Author(s):

Camille Grohe

Keyword(s):

Late Miocene ◽

Arabian Peninsula ◽

Coastal Region ◽

Abu Dhabi ◽

Abu Dhabi Emirate ◽

Postcranial Remains ◽

New Material

I describe new specimens of carnivoran mammals from the continental late Miocene Baynunah Formation, exposed in the western coastal region of Abu Dhabi Emirate. New material collected between 2002 and 2014 includes dental specimens of the mustelid Plesiogulo sp. and a large-sized hyaenid, postcranial remains and an upper canine of a large- sized machairodontine felid, postcrania and a tooth of a medium-sized felid, and postcrania of a medium-sized mustelid. The latter two are new taxonomic records for the Baynunah Formation. With a minimum of six species, the carnivoran assemblage from the Baynunah Formation is the richest known from the Miocene of the Arabian Peninsula.

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Chapala half-graben structure inferred. A magnetometric study

Geofísica Internacional ◽

10.22201/igeof.00167169p.2015.54.4.1699 ◽

2015 ◽

Vol 54 (4) ◽

Author(s):

Miguel Angel Alatorre-Zamora ◽

José Oscar Campos-Enríquez ◽

José Guadalupe Rosas-Elguera ◽

Laura Peña-García ◽

Roberto Maciel-Flores ◽

...

Keyword(s):

Late Miocene ◽

Large Scale ◽

Magnetic Anomalies ◽

High Amplitude ◽

Magnetic Survey ◽

Structural Studies ◽

General Terms ◽

Extensional Tectonic ◽

Half Graben ◽

Structural High

Many geologic and tectonic-structural studies refer to the Chapala lake structure in general terms as a graben (or more generally as rift). However, no formal study has addressed its structure. The Chapala Lake is located in a major topographic depression surrounded by broad middle to late Miocene volcanic-capped plateaus. We conducted a magnetic survey comprising five S-N lines crossing the Chapala Lake. One profile comprises a land extension (southwards along roads). Magnetic anomalies obtained are mainly smooth and large scale features associated to the sedimentary infill, local and high amplitude anomalies are due to shallow basaltic and andesitic tilted blocks, and highest amplitudes due to the outcropped basaltic flows of the Los Alacranes and Mezcala islands. The models obtained point to a large structural high located at the central depression portion that separates two structural lows. The structural lows correspond to half-graben type structures. Through the faults delimiting it were emplaced the basaltic flows of the Mezcala and Los Alacranes islands. The presence of half-graben type structures indicates that the crust has been subject to an extensional tectonic.

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Generalizability of GWA-Identified Genetic Risk Variants for Metabolic Traits to Populations from the Arabian Peninsula

Genes ◽

10.3390/genes12101637 ◽

2021 ◽

Vol 12 (10) ◽

pp. 1637

Author(s):

Prashantha Hebbar ◽

Mohamed Abu-Farha ◽

Jehad Abubaker ◽

Arshad Mohamed Channanath ◽

Fahd Al-Mulla ◽

...

Keyword(s):

Large Scale ◽

Arabian Peninsula ◽

Genetic Correlations ◽

Human Migration ◽

Metabolic Risk ◽

Arab Population ◽

Metabolic Traits ◽

Risk Variants ◽

Genome Wide ◽

Gwa Studies

The Arabian Peninsula, located at the nexus of Africa, Europe, and Asia, was implicated in early human migration. The Arab population is characterized by consanguinity and endogamy leading to inbreeding. Global genome-wide association (GWA) studies on metabolic traits under-represent the Arab population. Replicability of GWA-identified association signals in the Arab population has not been satisfactorily explored. It is important to assess how well GWA-identified findings generalize if their clinical interpretations are to benefit the target population. Our recent study from Kuwait, which performed genome-wide imputation and meta-analysis, observed 304 (from 151 genes) of the 4746 GWA-identified metabolic risk variants replicable in the Arab population. A recent large GWA study from Qatar found replication of 30 GWA-identified lipid risk variants. These complementing studies from the Peninsula increase the confidence in generalizing metabolic risk loci to the Arab population. However, both the studies reported a low extent of transferability. In this review, we examine the observed low transferability in the context of differences in environment, genetic correlations (allele frequencies, linkage disequilibrium, effect sizes, and heritability), and phenotype variance. We emphasize the need for large-scale GWA studies on deeply phenotyped cohorts of at least 20,000 Arab individuals. The review further presents GWA-identified metabolic risk variants generalizable to the Arab population.

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The Atmospheric Controls of Extreme Convective Events over the Southern Arabian Peninsula during the Transition Seasons

10.5194/egusphere-egu21-3234 ◽

2021 ◽

Author(s):

Narendra Reddy Nelli ◽

Diana Francis ◽

Ricardo Fonseca ◽

Rachid Abida ◽

Michael Weston ◽

...

Keyword(s):

Large Scale ◽

Arabian Peninsula ◽

Arabian Gulf ◽

Reanalysis Data ◽

Convective Systems ◽

Stratospheric Temperature ◽

Moisture Advection ◽

Mesoscale Convective ◽

Upper Level ◽

Warming World

<p>In this paper, the processes behind severe convective events over the Arabian Peninsula during spring and autumn seasons and their local-scale impacts are investigated using reanalysis data, satellite-derived and observational products. The focus on the transition seasons is justified as Mesoscale Convective Systems (MCSs) are more common at that time of the year, in particular in the months of March and April. The analysis of 48 events from 2000 to 2019 revealed that they are triggered by low-level wind convergence and moisture advection from the Arabian Sea, Arabian Gulf and/or Red Sea. An equatorward displacement and strengthening of the subtropical jet also precondition the environment, as does the presence of a mid-level trough. The latter is generally part of a large-scale pattern of anomalies that are equivalent barotropic in nature, and therefore likely a response to tropical or subtropical forcing. At more local-scales, a drying of the mid-troposphere between 850 and 250 hPa typically by 50%, a reduction of the upper-level winds by about 5 m s<sup>-1</sup>, and an increase in the upper-tropospheric and lower-stratospheric temperature on averaged by 2-3 K, are typically observed during a MCS event. Over the 20-year period, a statistically significant increase in the MCSs&#8217; spatial extent, intensity and duration over the UAE and surrounding region has been found, suggesting that such extreme events may be even more impactful in a hypothetical warming world. The rainfall they generate, on the other hand, shows an increase that is not statistically significant.</p>

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