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Emanuela Mattioli - One of the best experts on this subject based on the ideXlab platform.
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Calcareous nannofossil fluxes and size fluctuations in the middle Eocene (48-39 Ma) from Ocean Drilling Program (ODP) Site 1209 in the tropical Pacific Ocean
Palaeogeography Palaeoclimatology Palaeoecology, 2018Co-Authors: Celine Salaviale, Barbara Gollain, Emanuela MattioliAbstract:Pelagic carbonates constitute the majority of the ocean sediments, particularly since the Jurassic, and record climatic and oceanic changes. Cenozoic sediments record glacial and interglacial Periods, as well as thermal maxima, such as the PETM (Paleocene-Eocene Thermal Maximum) at ca. 56 Ma or the MECO (Middle Eocene Climatic Optimum) that dates back to ca. 40 Ma. The Paleogene Period shows variations in seawater temperature and atmospheric CO2, as well as fluctuations of the carbonate compensation depth (CCD). In order to understand the actions and feedbacks between climate (regulated amongst others by temperature, partial pressure of CO2, and atmospheric belts), CCD fluctuations and pelagic carbonate producers, the fluxes, assemblages and sizes of calcareous nannofossils were studied from sediments dated between 48 and 39 Ma, including the MECO interval. Calcareous nannofossils were analysed in from the ODP (Ocean Drilling Project) Leg 198 Site 1209A, Shatsky Rise located in the tropical Pacific. The previously proposed age model for Site 1209 has been slightly modified based on new calcareous nannofossil biostratigraphy recalibrated according to the GTS 2012. In a long-term perspective, calcareous nannofossil assemblages and taxa size show significant changes during the middle Eocene. Our data suggest that relatively oligotrophic conditions occurred between 48 and 45 Ma, interrupted by higher trophic conditions between 45 and 39 Ma, although oligotrophy occurred again during the MECO. Discoaster spp. show smaller sizes from 48 to 39 Ma, mirroring the global temperature decrease. At 40 Ma, during the MECO, large-sized reticulofenestrids with a peak of Reticulofenestra umbilicus (\textgreater 14 mu m) occurred, whereas smaller but heavily calcified Dictyococcites spp. peak in the aftermath of the MECO. Calcareous nannofossil fluxes show a significant increase with respect to background values during the CAEs (Carbonate Accumulation Event), although they are low during the MECO. Calcareous nannofossil fluxes seem to have had important impact on the oceanic carbon cycles, by creating a carbonate flux to the ocean interior, likely contributing to the CCD deepening.
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Calcareous nannofossil fluxes and size fluctuations in the middle Eocene (48–39 Ma) from Ocean Drilling Program (ODP) Site 1209 in the tropical Pacific Ocean
Palaeogeography Palaeoclimatology Palaeoecology, 2018Co-Authors: Celine Salaviale, Barbara Gollain, Emanuela MattioliAbstract:Abstract Pelagic carbonates constitute the majority of the ocean sediments, particularly since the Jurassic, and record climatic and oceanic changes. Cenozoic sediments record glacial and interglacial Periods, as well as thermal maxima, such as the PETM (Paleocene-Eocene Thermal Maximum) at ca. 56 Ma or the MECO (Middle Eocene Climatic Optimum) that dates back to ca. 40 Ma. The Paleogene Period shows variations in seawater temperature and atmospheric CO2, as well as fluctuations of the carbonate compensation depth (CCD). In order to understand the actions and feedbacks between climate (regulated amongst others by temperature, partial pressure of CO2, and atmospheric belts), CCD fluctuations and pelagic carbonate producers, the fluxes, assemblages and sizes of calcareous nannofossils were studied from sediments dated between 48 and 39 Ma, including the MECO interval. Calcareous nannofossils were analysed in from the ODP (Ocean Drilling Project) Leg 198 Site 1209A, Shatsky Rise located in the tropical Pacific. The previously proposed age model for Site 1209 has been slightly modified based on new calcareous nannofossil biostratigraphy recalibrated according to the GTS 2012. In a long-term perspective, calcareous nannofossil assemblages and taxa size show significant changes during the middle Eocene. Our data suggest that relatively oligotrophic conditions occurred between 48 and 45 Ma, interrupted by higher trophic conditions between 45 and 39 Ma, although oligotrophy occurred again during the MECO. Discoaster spp. show smaller sizes from 48 to 39 Ma, mirroring the global temperature decrease. At 40 Ma, during the MECO, large-sized reticulofenestrids with a peak of Reticulofenestra umbilicus (> 14 μm) occurred, whereas smaller but heavily calcified Dictyococcites spp. peak in the aftermath of the MECO. Calcareous nannofossil fluxes show a significant increase with respect to background values during the CAEs (Carbonate Accumulation Event), although they are low during the MECO. Calcareous nannofossil fluxes seem to have had important impact on the oceanic carbon cycles, by creating a carbonate flux to the ocean interior, likely contributing to the CCD deepening.
Celine Salaviale - One of the best experts on this subject based on the ideXlab platform.
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Calcareous nannofossil fluxes and size fluctuations in the middle Eocene (48-39 Ma) from Ocean Drilling Program (ODP) Site 1209 in the tropical Pacific Ocean
Palaeogeography Palaeoclimatology Palaeoecology, 2018Co-Authors: Celine Salaviale, Barbara Gollain, Emanuela MattioliAbstract:Pelagic carbonates constitute the majority of the ocean sediments, particularly since the Jurassic, and record climatic and oceanic changes. Cenozoic sediments record glacial and interglacial Periods, as well as thermal maxima, such as the PETM (Paleocene-Eocene Thermal Maximum) at ca. 56 Ma or the MECO (Middle Eocene Climatic Optimum) that dates back to ca. 40 Ma. The Paleogene Period shows variations in seawater temperature and atmospheric CO2, as well as fluctuations of the carbonate compensation depth (CCD). In order to understand the actions and feedbacks between climate (regulated amongst others by temperature, partial pressure of CO2, and atmospheric belts), CCD fluctuations and pelagic carbonate producers, the fluxes, assemblages and sizes of calcareous nannofossils were studied from sediments dated between 48 and 39 Ma, including the MECO interval. Calcareous nannofossils were analysed in from the ODP (Ocean Drilling Project) Leg 198 Site 1209A, Shatsky Rise located in the tropical Pacific. The previously proposed age model for Site 1209 has been slightly modified based on new calcareous nannofossil biostratigraphy recalibrated according to the GTS 2012. In a long-term perspective, calcareous nannofossil assemblages and taxa size show significant changes during the middle Eocene. Our data suggest that relatively oligotrophic conditions occurred between 48 and 45 Ma, interrupted by higher trophic conditions between 45 and 39 Ma, although oligotrophy occurred again during the MECO. Discoaster spp. show smaller sizes from 48 to 39 Ma, mirroring the global temperature decrease. At 40 Ma, during the MECO, large-sized reticulofenestrids with a peak of Reticulofenestra umbilicus (\textgreater 14 mu m) occurred, whereas smaller but heavily calcified Dictyococcites spp. peak in the aftermath of the MECO. Calcareous nannofossil fluxes show a significant increase with respect to background values during the CAEs (Carbonate Accumulation Event), although they are low during the MECO. Calcareous nannofossil fluxes seem to have had important impact on the oceanic carbon cycles, by creating a carbonate flux to the ocean interior, likely contributing to the CCD deepening.
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Calcareous nannofossil fluxes and size fluctuations in the middle Eocene (48–39 Ma) from Ocean Drilling Program (ODP) Site 1209 in the tropical Pacific Ocean
Palaeogeography Palaeoclimatology Palaeoecology, 2018Co-Authors: Celine Salaviale, Barbara Gollain, Emanuela MattioliAbstract:Abstract Pelagic carbonates constitute the majority of the ocean sediments, particularly since the Jurassic, and record climatic and oceanic changes. Cenozoic sediments record glacial and interglacial Periods, as well as thermal maxima, such as the PETM (Paleocene-Eocene Thermal Maximum) at ca. 56 Ma or the MECO (Middle Eocene Climatic Optimum) that dates back to ca. 40 Ma. The Paleogene Period shows variations in seawater temperature and atmospheric CO2, as well as fluctuations of the carbonate compensation depth (CCD). In order to understand the actions and feedbacks between climate (regulated amongst others by temperature, partial pressure of CO2, and atmospheric belts), CCD fluctuations and pelagic carbonate producers, the fluxes, assemblages and sizes of calcareous nannofossils were studied from sediments dated between 48 and 39 Ma, including the MECO interval. Calcareous nannofossils were analysed in from the ODP (Ocean Drilling Project) Leg 198 Site 1209A, Shatsky Rise located in the tropical Pacific. The previously proposed age model for Site 1209 has been slightly modified based on new calcareous nannofossil biostratigraphy recalibrated according to the GTS 2012. In a long-term perspective, calcareous nannofossil assemblages and taxa size show significant changes during the middle Eocene. Our data suggest that relatively oligotrophic conditions occurred between 48 and 45 Ma, interrupted by higher trophic conditions between 45 and 39 Ma, although oligotrophy occurred again during the MECO. Discoaster spp. show smaller sizes from 48 to 39 Ma, mirroring the global temperature decrease. At 40 Ma, during the MECO, large-sized reticulofenestrids with a peak of Reticulofenestra umbilicus (> 14 μm) occurred, whereas smaller but heavily calcified Dictyococcites spp. peak in the aftermath of the MECO. Calcareous nannofossil fluxes show a significant increase with respect to background values during the CAEs (Carbonate Accumulation Event), although they are low during the MECO. Calcareous nannofossil fluxes seem to have had important impact on the oceanic carbon cycles, by creating a carbonate flux to the ocean interior, likely contributing to the CCD deepening.
M Konert - One of the best experts on this subject based on the ideXlab platform.
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tibetan uplift prior to the eocene oligocene climate transition evidence from pollen analysis of the xining basin
Geology, 2008Co-Authors: Guillaume Dupontnivet, Carina Hoorn, M KonertAbstract:Uplift of the Tibetan Plateau and the Himalayas since the onset of the Indo-Asia collision is held responsible for Asian aridifi cation and monsoon intensifi cation, but may also have gradually cooled global climate, leading to the 34 Ma Eocene-Oligocene transition. To unravel the interplay between Tibetan uplift and global climate, proxy records of Asian paleoenvironments constrained by accurate age models are needed for the Paleogene Period. Here we report the 38 Ma appearance of high-altitude vegetation recovered from palynological assemblages in precisely dated lacustrine sediments from the Xining Basin of the northeastern Tibetan Plateau region. This result confi rms previous evidence for important regional uplift in the central and northern Tibetan Plateau regions during the early stage of the Indo-Asia collision. This is consistent with the idea that the associated increase in rock weathering and erosion contributed to lowering of atmospheric CO 2 , leading to the Eocene-Oligocene transition.
Barbara Gollain - One of the best experts on this subject based on the ideXlab platform.
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Calcareous nannofossil fluxes and size fluctuations in the middle Eocene (48-39 Ma) from Ocean Drilling Program (ODP) Site 1209 in the tropical Pacific Ocean
Palaeogeography Palaeoclimatology Palaeoecology, 2018Co-Authors: Celine Salaviale, Barbara Gollain, Emanuela MattioliAbstract:Pelagic carbonates constitute the majority of the ocean sediments, particularly since the Jurassic, and record climatic and oceanic changes. Cenozoic sediments record glacial and interglacial Periods, as well as thermal maxima, such as the PETM (Paleocene-Eocene Thermal Maximum) at ca. 56 Ma or the MECO (Middle Eocene Climatic Optimum) that dates back to ca. 40 Ma. The Paleogene Period shows variations in seawater temperature and atmospheric CO2, as well as fluctuations of the carbonate compensation depth (CCD). In order to understand the actions and feedbacks between climate (regulated amongst others by temperature, partial pressure of CO2, and atmospheric belts), CCD fluctuations and pelagic carbonate producers, the fluxes, assemblages and sizes of calcareous nannofossils were studied from sediments dated between 48 and 39 Ma, including the MECO interval. Calcareous nannofossils were analysed in from the ODP (Ocean Drilling Project) Leg 198 Site 1209A, Shatsky Rise located in the tropical Pacific. The previously proposed age model for Site 1209 has been slightly modified based on new calcareous nannofossil biostratigraphy recalibrated according to the GTS 2012. In a long-term perspective, calcareous nannofossil assemblages and taxa size show significant changes during the middle Eocene. Our data suggest that relatively oligotrophic conditions occurred between 48 and 45 Ma, interrupted by higher trophic conditions between 45 and 39 Ma, although oligotrophy occurred again during the MECO. Discoaster spp. show smaller sizes from 48 to 39 Ma, mirroring the global temperature decrease. At 40 Ma, during the MECO, large-sized reticulofenestrids with a peak of Reticulofenestra umbilicus (\textgreater 14 mu m) occurred, whereas smaller but heavily calcified Dictyococcites spp. peak in the aftermath of the MECO. Calcareous nannofossil fluxes show a significant increase with respect to background values during the CAEs (Carbonate Accumulation Event), although they are low during the MECO. Calcareous nannofossil fluxes seem to have had important impact on the oceanic carbon cycles, by creating a carbonate flux to the ocean interior, likely contributing to the CCD deepening.
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Calcareous nannofossil fluxes and size fluctuations in the middle Eocene (48–39 Ma) from Ocean Drilling Program (ODP) Site 1209 in the tropical Pacific Ocean
Palaeogeography Palaeoclimatology Palaeoecology, 2018Co-Authors: Celine Salaviale, Barbara Gollain, Emanuela MattioliAbstract:Abstract Pelagic carbonates constitute the majority of the ocean sediments, particularly since the Jurassic, and record climatic and oceanic changes. Cenozoic sediments record glacial and interglacial Periods, as well as thermal maxima, such as the PETM (Paleocene-Eocene Thermal Maximum) at ca. 56 Ma or the MECO (Middle Eocene Climatic Optimum) that dates back to ca. 40 Ma. The Paleogene Period shows variations in seawater temperature and atmospheric CO2, as well as fluctuations of the carbonate compensation depth (CCD). In order to understand the actions and feedbacks between climate (regulated amongst others by temperature, partial pressure of CO2, and atmospheric belts), CCD fluctuations and pelagic carbonate producers, the fluxes, assemblages and sizes of calcareous nannofossils were studied from sediments dated between 48 and 39 Ma, including the MECO interval. Calcareous nannofossils were analysed in from the ODP (Ocean Drilling Project) Leg 198 Site 1209A, Shatsky Rise located in the tropical Pacific. The previously proposed age model for Site 1209 has been slightly modified based on new calcareous nannofossil biostratigraphy recalibrated according to the GTS 2012. In a long-term perspective, calcareous nannofossil assemblages and taxa size show significant changes during the middle Eocene. Our data suggest that relatively oligotrophic conditions occurred between 48 and 45 Ma, interrupted by higher trophic conditions between 45 and 39 Ma, although oligotrophy occurred again during the MECO. Discoaster spp. show smaller sizes from 48 to 39 Ma, mirroring the global temperature decrease. At 40 Ma, during the MECO, large-sized reticulofenestrids with a peak of Reticulofenestra umbilicus (> 14 μm) occurred, whereas smaller but heavily calcified Dictyococcites spp. peak in the aftermath of the MECO. Calcareous nannofossil fluxes show a significant increase with respect to background values during the CAEs (Carbonate Accumulation Event), although they are low during the MECO. Calcareous nannofossil fluxes seem to have had important impact on the oceanic carbon cycles, by creating a carbonate flux to the ocean interior, likely contributing to the CCD deepening.
Yin Chen - One of the best experts on this subject based on the ideXlab platform.
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destruction of the eastern north china craton in a backarc setting evidence from crustal deformation kinematics
Gondwana Research, 2012Co-Authors: Dazhi Jiang, Bilong Zhang, Yin ChenAbstract:Abstract The eastern North China Craton (NCC) west of the Pacific Ocean has a long history of rifting from Early Cretaceous to the end of Paleogene when the craton experienced destruction and significant thinning of the lithosphere. The cause and geotectonic environment for this destruction remain controversial. We use a set of field observation including basin patterns, fault geometry and kinematics, fault plane slip data, dike distribution, and fabric data from metamorphic core complexes to determine the kinematic evolution of the deformation in the eastern NCC during this Period. We show that the principal extension direction in the eastern NCC evolved from WNW–ESE in the earliest-middle Early Cretaceous, via NW–SE in the latest Early Cretaceous, to nearly N–S in the Late Cretaceous–Paleogene. The movement history, from Late Mesozoic to Early Cenozoic, of the oceanic plates in the Pacific Ocean with respect to the eastern NCC is available from previous studies. The Izanagi Plate first subducted nearly orthogonally (WNW-wards) during earliest-middle Early Cretaceous time, and then moved obliquely (NNW-wards) in the latest Early Cretaceous while the relaying Pacific Plate moved generally northwards from the Late Cretaceous to Paleogene. Both the movement direction of oceanic plates and the principal extension direction of the continental deformation rotated clockwise. We suggest that such a correlation can be explained by the eastern NCC being in a backarc setting in the Cretaceous–Paleogene Period. The results support the backarc extensional model for the destruction and significant lithospheric thinning of the eastern NCC.