Pedological Iron/Al Extracts, Clast Analysis, and Coleoptera from Antarctic Paleosol 831: Evidence of a Middle Miocene or Earlier Climatic Optimum

2015 ◽  
Vol 123 (2) ◽  
pp. 113-132 ◽  
Author(s):  
William C. Mahaney
Keyword(s):  
Middle Miocene ◽  
Climatic Optimum

scholarly journals The Biogeography of Dromiciops in Southern South America: middle Miocene transgressions, speciation and associations with Nothofagus

2020 ◽  
Author(s):  
Julian F. Quintero-Galvis ◽  
Pablo Saenz-Agudelo ◽  
Juan L. Celis-Diez ◽  
Guillermo C. Amico ◽  
Soledad Vazquez ◽  
...  
Keyword(s):  
South America ◽  
Middle Miocene ◽  
Nuclear Dna ◽  
Divergence Time ◽  
Time Estimation ◽  
Southern South America ◽  
Divergence Time Estimation ◽  
Fossil Calibration ◽  
Biogeographic History ◽  
Climatic Optimum

AbstractAimSeveral geological events affecting Southern South America during the middle Miocene climatic optimum acted as important drivers of diversification to the biota. This is the case of Microbiotheria, for which Dromiciops is considered the sole surviving lineage, the sister group of Eomarsupialia (Australian marsupials). Three main Dromiciops genetic lineages are known, whose divergence was initially attributed to recent Pleistocene glaciations. Using fossil-calibrated dating on nuclear and mitochondrial genes, here we reevaluate this hypothesis and report an older (Miocenic) biogeographic history for the genus.LocationSouthern South America.MethodsPhylogenetic reconstruction using sequences from two mitochondrial DNA and four nuclear DNA genes in 159 specimens, from 31 sites across Chile and Argentina. Divergence time estimation using fossil calibration.ResultsOur phylogenetic analysis resolved four well supported clades with discrete geographic distributions. The oldest and most differentiated clade corresponds to that of the northern distribution (35.2°S to 39.3°S), which would be a different species (D. bozinovici, sensu D’elia et al. 2016). According to our estimations, this species shared a common ancestor with D. gliroides (southern clades) about 13 million years ago (95% CI: 6.4-25.3). The southern clades (39.6°S to 42.0°S), showed a divergence time ranging from 9.57 to 6.5 Mya. Strong genetic structure was detected from north to south but not across the Andes, or between Chiloé island/ mainland. Demographic equilibrium is inferred to the northern clade, and recent demographic expansions was detected in the central and southern clades.Main conclusionsThe whole diversification of Dromiciops occurred within the Miocene, being the Middle Miocene transgression (MMT), the massive marine flooding that covered several lowlands of the western face of los Andes between 38-48° S, the most likely diversifying force. This was the result of an increase in global sea levels due to the Miocene climatic optimum, which shaped the biogeographic origin of several species, including Nothofagus forests, the habitat main of Dromiciops.

FOSSIL PHYTOLITH ASSEMBLAGES FROM SOUTHERN PATAGONIA INDICATE CHANGING HABITATS DURING THE MIDDLE MIOCENE CLIMATIC OPTIMUM

2017 ◽  
Author(s):  
Camilla Crifò ◽  
◽  
Susana Bargo ◽  
José I. Cuitiño ◽  
Richard F. Kay ◽  
...  
Keyword(s):  
Middle Miocene ◽  
Southern Patagonia ◽  
Climatic Optimum

Origin of a widespread marine bonebed deposited during the middle Miocene Climatic Optimum

Geology ◽  
2009 ◽  
Vol 37 (6) ◽  
pp. 519-522 ◽  
Author(s):  
Nicholas D. Pyenson ◽  
Randall B. Irmis ◽  
Jere H. Lipps ◽  
Lawrence G. Barnes ◽  
Edward D. Mitchell ◽  
...  
Keyword(s):  
Middle Miocene ◽  
Climatic Optimum

scholarly journals The Mid Miocene Climatic Optimum (MMCO) Indication at Low Latitude Sediment Case Study: The Miocene Cibulakan Formation, Bogor Basin

2018 ◽  
Author(s):  
Wahyu Dwijo Santoso ◽  
Rubiyanto Kapid ◽  
Ben Ikhsan ◽  
Moehammad Ali Jambak ◽  
Dasapta Erwin Irawan
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Middle Miocene ◽  
Sea Surface ◽  
Early Miocene ◽  
Small Scale ◽  
Low Latitude ◽  
Temperature Changes ◽  
Climatic Optimum ◽  
Increasing Temperature

Global climatic event on Middle Miocene triggered by geology activity is called by Mid- Miocene Climatic Optimum (MMCO). This event was widely distributed and associated with increasing temperature and CO2 content in the atmosphere. The effect of MMCO was widely known the mid-latitude region, but still limited information in low latitude sediments. This study try to perform the effect of MMCO at Cibulakan Formation in which deposited in the low latitude basin, Bogor Basin. Fifty eights samples from Cileungsi River were taken at Cibulakan Formation and quantitative nannoplankton analysis was carried out for this study. Nannoplankton shows the sensitive response with sea surface temperature changes. Increasing of total population nannoplankton indicates the rising of temperature and dropping temperature is marked by decreasing population. The effect of sea surface temperature changes relates with salinity changes as the effect of evaporation. Helicosphaera carteri and Umbilicosphaera jafari were counted to know the salinity trend at Cibulakan Formation. Sea surfaces temperature changes was observed on Early Miocene which was influenced by small scale Early Miocene glaciation and active tectonic during this period. Warming temperature taken place on Middle Miocene as the effect of warm and open sea during Mid Miocene Climatic Optimum. Afterwards, hot temperature continued on Late Miocene triggered by global increasing temperature at Pacific Ocean and widely distribution of clean water at North West Java Basin.

scholarly journals Palaeoenvironmental evolution of Lake Gacko (Southern Bosnia and Herzegovina): Impact of the Middle Miocene Climatic Optimum on the Dinaride Lake System

2011 ◽  
Vol 299 (3-4) ◽  
pp. 475-492 ◽  
Author(s):  
Oleg Mandic ◽  
Arjan de Leeuw ◽  
Boško Vuković ◽  
Wout Krijgsman ◽  
Mathias Harzhauser ◽  
...  
Keyword(s):  
Bosnia And Herzegovina ◽  
Middle Miocene ◽  
Lake System ◽  
Climatic Optimum
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