New constraints on the palaeo-environmental conditions of the Eastern Paratethys: Implications from the Miocene Diatom Suite (Azerbaijan)

New Geochemical Insights Into Cenozoic Source Rocks in Azerbaijan: Implications for Petroleum Systems in the South Caspian Region

“…PMI, crocetane). Hence, oxic conditions, as postulated recently by Abdullayev et al (2021) based on redoxsensitive elements, can be excluded.…”

“…The top of the section is interpreted as older than 6.1 Ma based on the absence of the lithologically and biostratigraphically distinct sediments of the younger Pontian regional stage (van Baak et al, 2016). Mineralogy and element concentrations of the interval between 613 and 663 m have been studied by Abdullayev et al (2021; their Pereküşkül-Diatom section). Based on questionable correlations, the authors assumed a Karaganian to Konkian age for the interval.…”

Palaeo-environmental evolution of Central Asia during the Cenozoic: New insights from the continental sedimentary archive of the Valley of Lakes (Mongolia)

“…Sediment origin and variations in the detrital influx among the different provenance areas were depicted using discrimination plots calculated on the basis of major oxide compositions (Roser and Korsch, 1988). The weathering paths and intensities in the source rock areas were assessed through changes in the weathering indices, such as the chemical index of alteration (CIA), the chemical index of weathering (CIW) and the plagioclase index of alteration (PIA), which were calculated based on the major oxide compositions using the following equations (Nesbitt and Young, 1982;Abdullayev et al, 2021):…”

“…Minor amounts of TiO2 belong to rutile and anatase and traces of MnO and P2O5 correspond to Mn-oxides and apatite. The positive correlations of Cu, Ga, Rb and Zn with Al2O3 as well as Ce, La, Y and Zr with TiO2 and Sr with CaO point to their association with clay minerals (i.e., structural incorporation or sorption onto the clay mineral surface), heavy minerals and carbonate minerals, respectively (Abdullayev et al, 2021). Ba, Co, Cr, Hf, Nb, Ni, Pb, Sc, Th, V and U are inconspicuous due to lack of correlation with Al2O3 and TiO2 or low concentration in the samples.…”

“…The Cenozoic Era (66 Ma to the present day) saw several dramatic changes of the marine and continental ecosystems (e.g., evolution of large plankton feeders such as baleen whales, shift towards cold-water, high nutrient plankton assemblages at high latitude, expansion of terrestrial mammals) major tectonic events (e.g., opening of Southern Hemisphere Oceanic gateways, shift to the 4-layer structure of the modern ocean, collision of the African-Arabian-Eurasian plates, uplift of the Alpine and Himalayan mountain belt) and global climate forcing (e.g., change from greenhouse to icehouse conditions) (Cerling, 1997;Houben et al, 2013;Norris et al, 2013;Cermeño et al, 2015;Mutz et al, 2018;Komar and Zeebe, 2021). The acceleration of Cenozoic climate cooling started after the Early Eocene Climatic Optimum (EECO; ~52-50 Ma), with temperatures ~10-12 °C warmer than the modern deep ocean, followed by the appearance and expansion of the Antarctic ice-sheets after the Eocene-Oligocene Transition (EOT; ~34 Ma) and ultimately culminating in the extensive Northern Hemisphere glaciation of the Pleistocene (~2.6-0.01 Ma; Zachos et al, 2001;Lear et al, 2008;Mudelsee et al, 2014;Abdullayev et al, 2021). This long-term transition in Earth`s climate is well documented in marine sedimentary archives, but its impact on the evolution of continental ecosystems remains poorly constrained, mainly because continuous, well preserved terrestrial records are scarce and the responses to climate change in these settings are highly complex, depending on latitude, proximity to coast and mountain ranges, position relative to climatic winds, vegetation etc.…”