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Cari Zazo - One of the best experts on this subject based on the ideXlab platform.
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pleistocene raised marine terraces of the spanish mediterranean and atlantic coasts records of coastal uplift sea level highstands and climate changes
Marine Geology, 2003Co-Authors: Cari Zazo, Cristino J Dabrio, Bassam Ghaleb, Teresa Bardaji, Claude Hillairemarcel, Joseangel Gonzalezdelgado, Vicente SolerAbstract:Detailed geological mapping, morphostratigraphic, palaeontological and geochronological (uranium-series) analyses were undertaken on the raised marine terraces and interbedded terrestrial deposits along the Spanish peninsular and insular Atlantic and Mediterranean coasts. Several sets of Pleistocene shallow-marine to coastal deposits exposed in a staircase arrangement are interpreted as being emplaced during sea-level highstands coeval with Interglacials or interstadials correlating with marine Oxygen Isotopic Stages (OIS) 5a/5c, 5e, 7, 9/11 and older. Up to three highstands have been identified in deposits formed during OIS 5e. Close to the end of OIS 5e there is a record of sudden changes in sea-surface conditions and climate marked by the disappearance of a major proportion of the warm ‘Senegalese’ fauna, switches from oolitic to non-oolitic facies, and accumulation of boulder beaches. Dating of the coral Cladocora caespitosa, found in a layer that also contains Strombus bubonius, confirms the occurrence of warm fauna in the Mediterranean basin during OIS 7, as previously suggested by Hillaire-Marcel et al. (1986), Goy et al. (1986a,b), Zazo and Goy (1989). Also the occurrence of warm faunas in deposits corresponding to an older Interglacial, probably OIS 9 or 11, in the Balearic Islands suggests similar oceanographic conditions (sea-surface temperature, assuming constant salinity) during the last Interglacial and at least two Interglacials of the Middle Pleistocene in the western Mediterranean. A 2002 Elsevier Science B.V. All rights reserved.
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Pleistocene raised marine terraces of the Spanish Mediterranean and Atlantic coasts: records of coastal uplift, sea-level highstands and climate changes
Marine Geology, 2003Co-Authors: Cari Zazo, José Luis Goy, Cristino J Dabrio, Teresa Bardajı́, Claude Hillaire-marcel, Bassam Ghaleb, José-Ángel González-delgado, Vicente SolerAbstract:Detailed geological mapping, morphostratigraphic, palaeontological and geochronological (uranium-series)\ud analyses were undertaken on the raised marine terraces and interbedded terrestrial deposits along the Spanish\ud peninsular and insular Atlantic and Mediterranean coasts. Several sets of Pleistocene shallow-marine to coastal\ud deposits exposed in a staircase arrangement are interpreted as being emplaced during sea-level highstands coeval with\ud Interglacials or interstadials correlating with marine Oxygen Isotopic Stages (OIS) 5a/5c, 5e, 7, 9/11 and older. Up to\ud three highstands have been identified in deposits formed during OIS 5e. Close to the end of OIS 5e there is a record of\ud sudden changes in sea-surface conditions and climate marked by the disappearance of a major proportion of the\ud warm ‘Senegalese’ fauna, switches from oolitic to non-oolitic facies, and accumulation of boulder beaches. Dating of\ud the coral Cladocora caespitosa, found in a layer that also contains Strombus bubonius, confirms the occurrence of\ud warm fauna in the Mediterranean basin during OIS 7, as previously suggested by Hillaire-Marcel et al. (1986), Goy et\ud al. (1986a,b), Zazo and Goy (1989). Also the occurrence of warm faunas in deposits corresponding to an older\ud Interglacial, probably OIS 9 or 11, in the Balearic Islands suggests similar oceanographic conditions (sea-surface\ud temperature, assuming constant salinity) during the last Interglacial and at least two Interglacials of the Middle\ud Pleistocene in the western Mediterranean
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Interglacial sea levels
Quaternary International, 1999Co-Authors: Cari ZazoAbstract:Abstract Isotopic curves have been used as approximative estimators of global sea level. Calculations of the amplitude of sea-level variations during Interglacials, especially for the last Interglacial, are based on the study of emerged coral terraces. The application of different dating methods shows great uncertainty about the length of each Interglacial and also about the number, chronology and altitude of the different highstands that occur during each Interglacial. Data of raised marine terraces from areas with different geodynamic behaviour (Bermudas, Bahamas, Peru, Chile, Italy and Spain) are summarized in order to analyze the relationships between sea level and Interglacial stages. Two Interglacials have been identified for the early Pleistocene represented by two marine terraces with different highstands. During the early-middle Pleistocene, an Interglacial with several highstands is recorded in uplifted areas. During Isotopic Stage 11 at least one highstand with sea level equal or higher than present has been recorded. Similar sea-level behaviour can be suggested for Isotopic Stage 9. All the analyzed areas record two highstands during Isotopic Stage 7, when warm equatorial fauna migrate into the Mediterranean. During Isotopic Substage 5e at least two highstands took place with evidence of lowstands between them and at least one highstand during substage 5c with similar sea-level height above present MSL, except in Barbados and Bermuda. During Substage 5a at least one highstand has been recorded.
André Berger - One of the best experts on this subject based on the ideXlab platform.
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Interglacials of the last 800,000 years
Reviews of Geophysics, 2016Co-Authors: André Berger, Dominique Raynaud, Michel Crucifix, David A. Hodell, Clara Mangili, Jerry F. Mcmanus, Bette L. Otto-bliesner, K. Pol, Luke C Skinner, Polychronis C TzedakisAbstract:Interglacials, including the present (Holocene) period, are warm, low land ice extent (high sea level), end-members of glacial cycles. Based on a sea level definition, we identify eleven Interglacials in the last 800,000 years, a result that is robust to alternative definitions. Data compilations suggest that despite spatial heterogeneity, Marine Isotope Stages (MIS) 5e (last Interglacial) and 11c (~400 ka ago) were globally strong (warm), while MIS 13a (~500 ka ago) was cool at many locations. A step change in strength of Interglacials at 450 ka is apparent only in atmospheric CO2 and in Antarctic and deep ocean temperature. The onset of an Interglacial (glacial termination) seems to require a reducing precession parameter (increasing Northern Hemisphere summer insolation), but this condition alone is insufficient. Terminations involve rapid, nonlinear, reactions of ice volume, CO2, and temperature to external astronomical forcing. The precise timing of events may be modulated by millennial-scale climate change that can lead to a contrasting timing of maximum Interglacial intensity in each hemisphere. A variety of temporal trends is observed, such that maxima in the main records are observed either early or late in different Interglacials. The end of an Interglacial (glacial inception) is a slower process involving a global sequence of changes. Interglacials have been typically 10–30 ka long. The combination of minimal reduction in northern summer insolation over the next few orbital cycles, owing to low eccentricity, and high atmospheric greenhouse gas concentrations implies that the next glacial inception is many tens of millennia in the future.
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Response of Interglacial climate to insolation and CO2 during the past 800,000 years
2015Co-Authors: Qiuzhen Yin, André BergerAbstract:The climate of nine Interglacials of the past 800,000 years has been simulated with both snapshot and transient experiments using the model LOVECLIM. These simulations allow to investigate the relative contributions of insolation and CO2 to the intensity and duration of each Interglacial as well as the differences between the Interglacials at global and regional scales. The transient simulations which cover a full range of precession, obliquity and eccentricity allow to investigate the response of different climate variables at different latitudes to these three astronomical parameters. The results show that the relative contribution of insolation and CO2 on the warmth intensity varies from one Interglacial to another. They also show that CO2 plays a dominant role on the variations of the global annual mean temperature and the southern high latitude temperature and sea ice, whereas, insolation plays a dominant role on the variations of monsoon precipitation, vegetation and of the northern high latitude temperature and sea ice. The results also show that, compared to today, the past Interglacials are warmer during boreal summer and cooler during boreal winter leading to a warmer annual mean with varying length for different Interglacials. The warm interval of MIS-11 is the longest, confirming its long duration as found in proxy records. The long duration of MIS-11 is related to a particular combination of eccentricity, obliquity and precession as well as to a high CO2 concentration. The transient simulations allow also to look for past Interglacial analogues for the whole MIS-1 and its natural future. As far as the variations in both annual and seasonal temperatures are concerned, MIS-19 is the best analogue of MIS-1 and its natural near future. The differences between the simulated seasonal behaviour of the past Interglacials highlight the importance of seasonal climate reconstruction and therefore the necessity to obtain seasonal proxies.
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Response of the Interglacial climate to different astronomical forcing
2014Co-Authors: Qiuzhen Yin, André BergerAbstract:Interglacials of the last one million years are a few thousands to tens of thousands of years long. Transient climate simulation is probably the best way to understand their climate behavior. In the mean time, before transient simulation is available, snapshot simulation at particularly well suited dates helps to understand how the Interglacial climate behaves. Two dates are evident: the peak of the Interglacial which generally corresponds to a time when northern hemisphere fall occurs at perihelion, and the date when northern hemisphere summer occurs at perihelion just preceding the Interglacial peak. The simulation at the date when northern hemisphere summer at perihelion has the advantages: 1. to maximize the forcing signal; 2. to help comparing more easily the Interglacials between them together as the only astronomical difference arises from obliquity and eccentricity; and 3. to take into account the fact the climate system response to the astronomical forcing with a lag of about 3-5 thousands of years. The simulation at the peak of the Interglacials gives a first instantaneously view of the climate in equilibrium with the forcing whatever it is at that particular date. The purpose of this paper is to compare both simulations at each Interglacial and the Interglacials between each other. The differences in the simulated results between these two dates are quite large at regional and seasonal scales. For example, compared with the simulation of northern hemisphere summer at perihelion, the annual climate at the peak of the Interglacials is much cooler in northern mid-high latitudes and warmer in tropical-subtropical regions. These climatic differences between the two dates show the importance of the chronology when proxy records and simulation results are compared. Transient simulations are expected to smooth out this difficulty.
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Interglacials of the last 800 ka and possible Pleistocene analogues of the Holocene
2014Co-Authors: Qiuzhen Yin, André BergerAbstract:To understand better our current Interglacial and its future, we have investigated the response of the climate system to insolation and GHG during the warm intervals (Climatic Optimum) of the Interglacials over the past 800,000 years using both LOVECLIM (Yin and Berger, 2010, 2012; Yin, 2013) and CCSM3 (Herold et al., 2012; Nikolova et al., 2013). A particular attention is paid to the 5 warmest Interglacials MIS-1, -5, -9, -11 and -19. If we identify the peaks of the Interglacials with NH summer at perihelion, MIS-1, MIS-11 and MIS-19 show a pretty similar latitudinal and seasonal distribution of the incoming solar radiation. When compared to the average of the last 9 Interglacials, they are under-insolated over the whole globe during boreal summer and are over-insolated during boreal winter with a maximum at the South Pole. This insolation distribution leads to a cooling over all the continents in boreal summer and to a warming over the whole Earth, except the Arctic, in boreal winter. A warming over the Southern Ocean in austral winter occurs during MIS-1 and MIS-19 due to the summer remnant effect of insolation. However, this does not happen in MIS11 because the large global cooling during this season is dominating the remnant effect of the austral summer. This leads to MIS-11 being a cool insolation-induced Interglacials and thus not as good an analogue of MIS-1 as MIS-19, at least as far as insolation is concerned. The CO2e of MIS-1 and MIS-19 is also practically the same (265 ppmv) but is larger for MIS-11 (286 ppmv). This pretty low value for MIS-1 and MIS-19 cools the Earth, reinforcing the insolation-induced cooling during boreal summer and moderating the warming during boreal winter. The reverse happens for MIS-11 for which its higher value allows it to be finally classified among the warm Interglacials. The best analogue to MIS-1 depends therefore upon the criteria used to select such an analogue. If the Interglacial peaks are considered, their global annual mean temperatures are slightly lower than when NH summer occurs at perihelion due to a smaller obliquity and to NH fall instead of summer occurring at perihelion. MIS-5 and MIS-9 remain the warmest Interglacials. MIS-11 and MIS-19 are now globally cooler than MIS-1 with a larger temperature gradient between the low and the high latitudes and no good analogue of MIS-1 can be found. All snapshot simulations of the five Interglacials show a global annual mean temperature higher than pre-industrial time, except for the MIS-19 peak simulation. This similarity between the climate of MIS-19 at its δ18O peak and of the pre-industrial time extends to the regional scale and to precipitation. This leads to the possibility of using the MIS-19 climate at its δ18O peak as an analogue for the natural climate of the present-day and the next centuries, and underlines the necessity of obtaining more proxy-based climate reconstructions of high temporal resolution during MIS-19. In the transient simulations, the past Interglacials are much warmer than PI in JJA, slightly warmer at the annual scale but cooler in DJF. This can be explained by the relatively small obliquity at pre-industrial time and its NH summer occurring at aphelion, both leading to much less insolation received by the Earth during boreal summer. In all simulations, the Interglacials MIS-9 and MIS-5 are the warmest over the last 800 ka and, as such, are considered as analogues for our CO2-induced future warm Interglacial, although their astronomical forcings are largely different from MIS-1 and its future. MIS-9 is the warmest and MIS-5, which is generally assumed to be a good analogue for the future warmth of our Interglacial, is slightly warmer than the simulated present-day climate. If we look now for analogues of the whole Holocene and its future, it must be stressed that the next minimum of eccentricity at the 400-ka time scale is approaching. With this and a CO2 concentration at the Interglacial level, and even larger under human influence, our Interglacial was predicted to be exceptionally long (Berger and Loutre, 2002) from a simulation where a simple ice-sheet model was interactively coupled to the rest of the climate system. The same happened during MIS-11, its long duration having been confirmed by the EPICA record (Jouzel et al., 2007).
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individual contribution of insolation and co2 to the Interglacial climates of the past 800 000 years
Climate Dynamics, 2012Co-Authors: Qiuzhen Yin, André BergerAbstract:The individual contributions of insolation and greenhouse gases (GHG) to the Interglacial climates of the past 800,000 years are quantified through simulations with a model of reduced complexity LOVECLIM and using the factor separation technique. The Interglacials are compared in terms of their forcings and responses of surface air temperature, vegetation and sea ice. The results show that the relative magnitude of the simulated Interglacials is in reasonable agreement with proxy data. GHG plays a dominant role on the variations of the annual mean temperature of both the Globe and the southern high latitudes, whereas, insolation plays a dominant role on the variations of tree fraction, precipitation and of the northern high latitude temperature and sea ice. The Mid-Brunhes Event (MBE) appears to be significant only in GHG and climate variables dominated by it. The results also show that the relative importance of GHG and insolation on the warmth intensity varies from one Interglacial to another. For the warmest (MIS-9 and MIS-5) and coolest (MIS-17 and MIS-13) Interglacials, GHG and insolation reinforce each other. MIS-11 (MIS-15) is a warm (cool) Interglacial due to its high (low) GHG concentration, its insolation contributing to a cooling (warming). MIS-7, although with high GHG concentrations, can not be classified as a warm Interglacial due to it large insolation-induced cooling. Related to these two forcings, MIS-19 appears to be the best analogue for MIS-1. In the response to insolation, the annual mean temperatures averaged over the globe and over southern high latitudes are highly linearly correlated with obliquity. However, precession becomes important in the temperature of the northern high latitudes and controls the tree fraction globally. Over the polar oceans, the response during the local winters, although the available energy is small, is larger than during the local summers due to the summer remnant effect. The sensitivity to double CO2 is the highest for the coolest Interglacial.
Qiuzhen Yin - One of the best experts on this subject based on the ideXlab platform.
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Response of Interglacial climate to insolation and CO2 during the past 800,000 years
2015Co-Authors: Qiuzhen Yin, André BergerAbstract:The climate of nine Interglacials of the past 800,000 years has been simulated with both snapshot and transient experiments using the model LOVECLIM. These simulations allow to investigate the relative contributions of insolation and CO2 to the intensity and duration of each Interglacial as well as the differences between the Interglacials at global and regional scales. The transient simulations which cover a full range of precession, obliquity and eccentricity allow to investigate the response of different climate variables at different latitudes to these three astronomical parameters. The results show that the relative contribution of insolation and CO2 on the warmth intensity varies from one Interglacial to another. They also show that CO2 plays a dominant role on the variations of the global annual mean temperature and the southern high latitude temperature and sea ice, whereas, insolation plays a dominant role on the variations of monsoon precipitation, vegetation and of the northern high latitude temperature and sea ice. The results also show that, compared to today, the past Interglacials are warmer during boreal summer and cooler during boreal winter leading to a warmer annual mean with varying length for different Interglacials. The warm interval of MIS-11 is the longest, confirming its long duration as found in proxy records. The long duration of MIS-11 is related to a particular combination of eccentricity, obliquity and precession as well as to a high CO2 concentration. The transient simulations allow also to look for past Interglacial analogues for the whole MIS-1 and its natural future. As far as the variations in both annual and seasonal temperatures are concerned, MIS-19 is the best analogue of MIS-1 and its natural near future. The differences between the simulated seasonal behaviour of the past Interglacials highlight the importance of seasonal climate reconstruction and therefore the necessity to obtain seasonal proxies.
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Response of the Interglacial climate to different astronomical forcing
2014Co-Authors: Qiuzhen Yin, André BergerAbstract:Interglacials of the last one million years are a few thousands to tens of thousands of years long. Transient climate simulation is probably the best way to understand their climate behavior. In the mean time, before transient simulation is available, snapshot simulation at particularly well suited dates helps to understand how the Interglacial climate behaves. Two dates are evident: the peak of the Interglacial which generally corresponds to a time when northern hemisphere fall occurs at perihelion, and the date when northern hemisphere summer occurs at perihelion just preceding the Interglacial peak. The simulation at the date when northern hemisphere summer at perihelion has the advantages: 1. to maximize the forcing signal; 2. to help comparing more easily the Interglacials between them together as the only astronomical difference arises from obliquity and eccentricity; and 3. to take into account the fact the climate system response to the astronomical forcing with a lag of about 3-5 thousands of years. The simulation at the peak of the Interglacials gives a first instantaneously view of the climate in equilibrium with the forcing whatever it is at that particular date. The purpose of this paper is to compare both simulations at each Interglacial and the Interglacials between each other. The differences in the simulated results between these two dates are quite large at regional and seasonal scales. For example, compared with the simulation of northern hemisphere summer at perihelion, the annual climate at the peak of the Interglacials is much cooler in northern mid-high latitudes and warmer in tropical-subtropical regions. These climatic differences between the two dates show the importance of the chronology when proxy records and simulation results are compared. Transient simulations are expected to smooth out this difficulty.
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Interglacials of the last 800 ka and possible Pleistocene analogues of the Holocene
2014Co-Authors: Qiuzhen Yin, André BergerAbstract:To understand better our current Interglacial and its future, we have investigated the response of the climate system to insolation and GHG during the warm intervals (Climatic Optimum) of the Interglacials over the past 800,000 years using both LOVECLIM (Yin and Berger, 2010, 2012; Yin, 2013) and CCSM3 (Herold et al., 2012; Nikolova et al., 2013). A particular attention is paid to the 5 warmest Interglacials MIS-1, -5, -9, -11 and -19. If we identify the peaks of the Interglacials with NH summer at perihelion, MIS-1, MIS-11 and MIS-19 show a pretty similar latitudinal and seasonal distribution of the incoming solar radiation. When compared to the average of the last 9 Interglacials, they are under-insolated over the whole globe during boreal summer and are over-insolated during boreal winter with a maximum at the South Pole. This insolation distribution leads to a cooling over all the continents in boreal summer and to a warming over the whole Earth, except the Arctic, in boreal winter. A warming over the Southern Ocean in austral winter occurs during MIS-1 and MIS-19 due to the summer remnant effect of insolation. However, this does not happen in MIS11 because the large global cooling during this season is dominating the remnant effect of the austral summer. This leads to MIS-11 being a cool insolation-induced Interglacials and thus not as good an analogue of MIS-1 as MIS-19, at least as far as insolation is concerned. The CO2e of MIS-1 and MIS-19 is also practically the same (265 ppmv) but is larger for MIS-11 (286 ppmv). This pretty low value for MIS-1 and MIS-19 cools the Earth, reinforcing the insolation-induced cooling during boreal summer and moderating the warming during boreal winter. The reverse happens for MIS-11 for which its higher value allows it to be finally classified among the warm Interglacials. The best analogue to MIS-1 depends therefore upon the criteria used to select such an analogue. If the Interglacial peaks are considered, their global annual mean temperatures are slightly lower than when NH summer occurs at perihelion due to a smaller obliquity and to NH fall instead of summer occurring at perihelion. MIS-5 and MIS-9 remain the warmest Interglacials. MIS-11 and MIS-19 are now globally cooler than MIS-1 with a larger temperature gradient between the low and the high latitudes and no good analogue of MIS-1 can be found. All snapshot simulations of the five Interglacials show a global annual mean temperature higher than pre-industrial time, except for the MIS-19 peak simulation. This similarity between the climate of MIS-19 at its δ18O peak and of the pre-industrial time extends to the regional scale and to precipitation. This leads to the possibility of using the MIS-19 climate at its δ18O peak as an analogue for the natural climate of the present-day and the next centuries, and underlines the necessity of obtaining more proxy-based climate reconstructions of high temporal resolution during MIS-19. In the transient simulations, the past Interglacials are much warmer than PI in JJA, slightly warmer at the annual scale but cooler in DJF. This can be explained by the relatively small obliquity at pre-industrial time and its NH summer occurring at aphelion, both leading to much less insolation received by the Earth during boreal summer. In all simulations, the Interglacials MIS-9 and MIS-5 are the warmest over the last 800 ka and, as such, are considered as analogues for our CO2-induced future warm Interglacial, although their astronomical forcings are largely different from MIS-1 and its future. MIS-9 is the warmest and MIS-5, which is generally assumed to be a good analogue for the future warmth of our Interglacial, is slightly warmer than the simulated present-day climate. If we look now for analogues of the whole Holocene and its future, it must be stressed that the next minimum of eccentricity at the 400-ka time scale is approaching. With this and a CO2 concentration at the Interglacial level, and even larger under human influence, our Interglacial was predicted to be exceptionally long (Berger and Loutre, 2002) from a simulation where a simple ice-sheet model was interactively coupled to the rest of the climate system. The same happened during MIS-11, its long duration having been confirmed by the EPICA record (Jouzel et al., 2007).
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insolation induced mid brunhes transition in southern ocean ventilation and deep ocean temperature
Nature, 2013Co-Authors: Qiuzhen YinAbstract:Glacial–Interglacial cycles characterized by long cold periods interrupted by short periods of warmth are the dominant feature of Pleistocene climate, with the relative intensity and duration of past and future Interglacials being of particular interest for civilization. The Interglacials after 430,000 years ago were characterized by warmer climates and higher atmospheric concentrations of carbon dioxide than the Interglacials before, but the cause of this climatic transition (the so-called mid-Brunhes event (MBE)) is unknown. Here I show, on the basis of model simulations, that in response to insolation changes only, feedbacks between sea ice, temperature, evaporation and salinity caused vigorous pre-MBE Antarctic bottom water formation and Southern Ocean ventilation. My results also show that strong westerlies increased the pre-MBE overturning in the Southern Ocean via an increased latitudinal insolation gradient created by changes in eccentricity during austral winter and by changes in obliquity during austral summer. The stronger bottom water formation led to a cooler deep ocean during the older Interglacials. These insolation-induced differences in the deep-sea temperature and in the Southern Ocean ventilation between the more recent Interglacials and the older ones were not expected, because there is no straightforward systematic difference in the astronomical parameters between the Interglacials before and after 430,000 years ago. Rather than being a real ‘event’, the apparent MBE seems to have resulted from a series of individual Interglacial responses—including notable exceptions to the general pattern—to various combinations of insolation conditions. Consequently, assuming no anthropogenic interference, future Interglacials may have pre- or post-MBE characteristics without there being a systematic change in forcings. These findings are a first step towards understanding the magnitude change of the Interglacial carbon dioxide concentration around 430,000 years ago.
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individual contribution of insolation and co2 to the Interglacial climates of the past 800 000 years
Climate Dynamics, 2012Co-Authors: Qiuzhen Yin, André BergerAbstract:The individual contributions of insolation and greenhouse gases (GHG) to the Interglacial climates of the past 800,000 years are quantified through simulations with a model of reduced complexity LOVECLIM and using the factor separation technique. The Interglacials are compared in terms of their forcings and responses of surface air temperature, vegetation and sea ice. The results show that the relative magnitude of the simulated Interglacials is in reasonable agreement with proxy data. GHG plays a dominant role on the variations of the annual mean temperature of both the Globe and the southern high latitudes, whereas, insolation plays a dominant role on the variations of tree fraction, precipitation and of the northern high latitude temperature and sea ice. The Mid-Brunhes Event (MBE) appears to be significant only in GHG and climate variables dominated by it. The results also show that the relative importance of GHG and insolation on the warmth intensity varies from one Interglacial to another. For the warmest (MIS-9 and MIS-5) and coolest (MIS-17 and MIS-13) Interglacials, GHG and insolation reinforce each other. MIS-11 (MIS-15) is a warm (cool) Interglacial due to its high (low) GHG concentration, its insolation contributing to a cooling (warming). MIS-7, although with high GHG concentrations, can not be classified as a warm Interglacial due to it large insolation-induced cooling. Related to these two forcings, MIS-19 appears to be the best analogue for MIS-1. In the response to insolation, the annual mean temperatures averaged over the globe and over southern high latitudes are highly linearly correlated with obliquity. However, precession becomes important in the temperature of the northern high latitudes and controls the tree fraction globally. Over the polar oceans, the response during the local winters, although the available energy is small, is larger than during the local summers due to the summer remnant effect. The sensitivity to double CO2 is the highest for the coolest Interglacial.
Xixi Zhao - One of the best experts on this subject based on the ideXlab platform.
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magnetostratigraphic and environmental implications of greigite fe3s4 formation from hole u1433a of the iodp expedition 349 south china sea
Marine Geology, 2017Co-Authors: Zongqi Duan, Qingsong Liu, Congcong Gai, Xixi ZhaoAbstract:Abstract A detailed magnetic analysis has been done on sedimentary core of the International Ocean Discovery Program (IODP) Site U1433A during Leg 349 in the South China Sea (SCS). Results show that dominant carriers of the natural remanent magnetization are greigite and (titano) magnetite. The major shift in both declination and inclination at ~ 185 mbsf is assigned to the Matuyama-Brunhes reversal boundary (~ 0.773 Ma). Constrained by biostratigraphic ages, variations in magnetic parameters of the core can be well correlated to the marine oxygen isotope record at glacial/Interglacial cycles. Low values of concentration-dependent magnetic parameters correspond to the Interglacials, and vice versa. During the Interglacial periods, the dominant magnetic minerals are detrital (titano) magnetite and have relatively coarser grain sizes, while fine-grained greigites dominate the glacial periods. This indicates that during the glacials, greigite prevails at the anoxic condition with amount of terrigenous iron oxide caused by the disconnection between the SCS and the Indian Ocean and the exposure of shelf, but digenesis is suppressed at the opposite environment by the high sea level (Interglacials). Thus, the preservation/sulfide process of (titano) magnetite is intimately related to the transformation of sea level changes with the monsoon-related rainfall caused by the glacial/Interglacial variation.
Vicente Soler - One of the best experts on this subject based on the ideXlab platform.
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pleistocene raised marine terraces of the spanish mediterranean and atlantic coasts records of coastal uplift sea level highstands and climate changes
Marine Geology, 2003Co-Authors: Cari Zazo, Cristino J Dabrio, Bassam Ghaleb, Teresa Bardaji, Claude Hillairemarcel, Joseangel Gonzalezdelgado, Vicente SolerAbstract:Detailed geological mapping, morphostratigraphic, palaeontological and geochronological (uranium-series) analyses were undertaken on the raised marine terraces and interbedded terrestrial deposits along the Spanish peninsular and insular Atlantic and Mediterranean coasts. Several sets of Pleistocene shallow-marine to coastal deposits exposed in a staircase arrangement are interpreted as being emplaced during sea-level highstands coeval with Interglacials or interstadials correlating with marine Oxygen Isotopic Stages (OIS) 5a/5c, 5e, 7, 9/11 and older. Up to three highstands have been identified in deposits formed during OIS 5e. Close to the end of OIS 5e there is a record of sudden changes in sea-surface conditions and climate marked by the disappearance of a major proportion of the warm ‘Senegalese’ fauna, switches from oolitic to non-oolitic facies, and accumulation of boulder beaches. Dating of the coral Cladocora caespitosa, found in a layer that also contains Strombus bubonius, confirms the occurrence of warm fauna in the Mediterranean basin during OIS 7, as previously suggested by Hillaire-Marcel et al. (1986), Goy et al. (1986a,b), Zazo and Goy (1989). Also the occurrence of warm faunas in deposits corresponding to an older Interglacial, probably OIS 9 or 11, in the Balearic Islands suggests similar oceanographic conditions (sea-surface temperature, assuming constant salinity) during the last Interglacial and at least two Interglacials of the Middle Pleistocene in the western Mediterranean. A 2002 Elsevier Science B.V. All rights reserved.
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Pleistocene raised marine terraces of the Spanish Mediterranean and Atlantic coasts: records of coastal uplift, sea-level highstands and climate changes
Marine Geology, 2003Co-Authors: Cari Zazo, José Luis Goy, Cristino J Dabrio, Teresa Bardajı́, Claude Hillaire-marcel, Bassam Ghaleb, José-Ángel González-delgado, Vicente SolerAbstract:Detailed geological mapping, morphostratigraphic, palaeontological and geochronological (uranium-series)\ud analyses were undertaken on the raised marine terraces and interbedded terrestrial deposits along the Spanish\ud peninsular and insular Atlantic and Mediterranean coasts. Several sets of Pleistocene shallow-marine to coastal\ud deposits exposed in a staircase arrangement are interpreted as being emplaced during sea-level highstands coeval with\ud Interglacials or interstadials correlating with marine Oxygen Isotopic Stages (OIS) 5a/5c, 5e, 7, 9/11 and older. Up to\ud three highstands have been identified in deposits formed during OIS 5e. Close to the end of OIS 5e there is a record of\ud sudden changes in sea-surface conditions and climate marked by the disappearance of a major proportion of the\ud warm ‘Senegalese’ fauna, switches from oolitic to non-oolitic facies, and accumulation of boulder beaches. Dating of\ud the coral Cladocora caespitosa, found in a layer that also contains Strombus bubonius, confirms the occurrence of\ud warm fauna in the Mediterranean basin during OIS 7, as previously suggested by Hillaire-Marcel et al. (1986), Goy et\ud al. (1986a,b), Zazo and Goy (1989). Also the occurrence of warm faunas in deposits corresponding to an older\ud Interglacial, probably OIS 9 or 11, in the Balearic Islands suggests similar oceanographic conditions (sea-surface\ud temperature, assuming constant salinity) during the last Interglacial and at least two Interglacials of the Middle\ud Pleistocene in the western Mediterranean