The Experts below are selected from a list of 2298 Experts worldwide ranked by ideXlab platform
Kurt Lambeck - One of the best experts on this subject based on the ideXlab platform.
-
the anatomy of interglacial sea levels the relationship between sea levels and ice volumes during the last interglacial
Earth and Planetary Science Letters, 2012Co-Authors: Kurt Lambeck, Anthony W Purcell, Andrea DuttonAbstract:Abstract The elevations and chronology of interglacial shorelines and other sea-level indicators provide information on ice volumes for these earlier periods compared with today. But, as for the Holocene, the relationship between sea levels and ice volumes for earlier interglacials is not simple because of the planet's deformational, gravitational and rotational response to changes in ice-water loads (glacio-hydro Isostasy). In particular, the pattern of global sea level for a particular interglacial will be a function of the earth and ocean response to ice loads applied before, during and after the interglacial in question. This paper examines the role of glacio-hydro Isostasy during these glacial cycles to make three key points. The first is to demonstrate why interglacial sea levels cannot be interpreted directly in terms of ice volume. The second is to illustrate the spatial variability that can be expected in interglacial sea levels because of the Earth's isostatic response to changing ice and water loads and to demonstrate why observations from different localities should not be combined into a single sea-level function without first correcting for differential isostatic effects. The third addresses the question whether, in the absence of perfect knowledge of the ice sheets and earth rheology, inferences can be made about ice volumes during an interglacial. We conclude that if these isostatic factors are ignored, interpretations of interglacial sea levels can lead to serious errors in the inferences about ice volumes during the interglacials.
-
Sea-level history of the Gulf of Mexico since the Last Glacial Maximum with implications for the melting history of the Laurentide Ice Sheet
Quaternary Science Reviews, 2007Co-Authors: Alexander R. Simms, Kurt Lambeck, Anthony W Purcell, John B. Anderson, Antonio B. RodriguezAbstract:Abstract Sea-level records from the Gulf of Mexico at the Last Glacial Maximum, 20 ka, are up to 35 m higher than time-equivalent sea-level records from equatorial regions. The most popular hypothesis for explaining this disparity has been uplift due to the forebulge created by loading from Mississippi River sediments. Using over 50 new radiocarbon dates as well as existing published data obtained from shallow-marine deposits within the northern Gulf of Mexico and numerical models simulating the impact of loading due to the Mississippi Fan and glacio-hydro-Isostasy, we test several possible explanations for this sea-level disparity. We find that neither a large radiocarbon reservoir, sedimentary loading due to the Mississippi Fan, nor large-scale regional uplift can explain this disparity. We do find that with an appropriate model for the Laurentide Ice Sheet, the observations from the Gulf of Mexico can be explained by the process of glacio-hydro-Isostasy. Our analysis suggests that in order to explain this disparity one must consider a Laurentide Ice Sheet reconstruction with less ice from 15 ka to its disappearance 6 ka and more ice from the Last Glacial Maximum to 15 ka than some earlier models have suggested. This supports a Laurentide contribution to meltwater pulse 1-A, which could not have come entirely from its southern sector.
-
sea level change along the italian coast for the past 10 000 yr
Quaternary Science Reviews, 2004Co-Authors: Kurt Lambeck, Fabrizio Antonioli, Anthony W Purcell, S SilenziAbstract:Relative sea-level change along the Italian coast and adjacent seas—the combined result of eustasy, glacio-hydro-Isostasy and vertical tectonic motion—exhibits considerable spatial and temporal variability throughout the Holocene. The tectonic contribution can be evaluated from the elevation of MIS 5.5 shoreline-markers that are well developed in many localities and the eustatic and isostatic contributions can be predicted from models of ice sheets and earth rheology. Discrepancies between observed Holocene sea levels and model predicted values provide the information for refiningthe model parameters, includingthe tectonic rates of vertical movement. Recent and new Holocene and MIS 5.5 information from 30 sites in Italy has been evaluated and compared with model results to calibrate the predictive model. The resultingparameters for the earth rheology and for the eustatic (ice-volume equivalent) sea-level function are consistent with results from regions outside of the Mediterranean and reflect global values. Using the calibrated model parameters the relative sea-level change due to eustasy and the concomitant Isostasy is predicted across the central Mediterranean region. Holocene tectonic rates of vertical motion are also given for the Italian coastal zone. At most sites where the MIS 5.5 shoreline occurs above or below its ‘tectonically stable’ position, the inferred rates of vertical crustal displacements are consistent with the assumption that average rates for the past B125,000 years are comparable to the average Holocene rates, but at some locations in eastern Sicily and southern Calabria the Holocene rates exceed the longer term average rates. r 2004 Elsevier Ltd. All rights reserved.
-
sea level change along the italian coast for the past 10 000 yr
Quaternary Science Reviews, 2004Co-Authors: Kurt Lambeck, Fabrizio Antonioli, Anthony W Purcell, S SilenziAbstract:Relative sea-level change along the Italian coast and adjacent seas—the combined result of eustasy, glacio-hydro-Isostasy and vertical tectonic motion—exhibits considerable spatial and temporal variability throughout the Holocene. The tectonic contribution can be evaluated from the elevation of MIS 5.5 shoreline-markers that are well developed in many localities and the eustatic and isostatic contributions can be predicted from models of ice sheets and earth rheology. Discrepancies between observed Holocene sea levels and model predicted values provide the information for refiningthe model parameters, includingthe tectonic rates of vertical movement. Recent and new Holocene and MIS 5.5 information from 30 sites in Italy has been evaluated and compared with model results to calibrate the predictive model. The resultingparameters for the earth rheology and for the eustatic (ice-volume equivalent) sea-level function are consistent with results from regions outside of the Mediterranean and reflect global values. Using the calibrated model parameters the relative sea-level change due to eustasy and the concomitant Isostasy is predicted across the central Mediterranean region. Holocene tectonic rates of vertical motion are also given for the Italian coastal zone. At most sites where the MIS 5.5 shoreline occurs above or below its ‘tectonically stable’ position, the inferred rates of vertical crustal displacements are consistent with the assumption that average rates for the past B125,000 years are comparable to the average Holocene rates, but at some locations in eastern Sicily and southern Calabria the Holocene rates exceed the longer term average rates. r 2004 Elsevier Ltd. All rights reserved.
-
geological causes of recent 100 yr vertical land movement in the netherlands
Tectonophysics, 1998Co-Authors: Henk Kooi, Kurt Lambeck, Paul Johnston, Catherine Smither, Ronald MolendijkAbstract:Abstract Geodetic levelling data record differential vertical movements of the top of the Pleistocene sands of up to 1.5 mm/year in the Netherlands over the last century. We compare these movements to (a) mean tectonic, isostatic and compaction movements at time scales of millions of years obtained by backstripping of Cenozoic stratigraphy, and (b) estimates of recent (∼100 yr) movements from process modelling of Isostasy (glacio- and hydro-Isostasy) and compaction. The process rates at time scales of millions of years are insufficient to account for the geodetic observations by an order of magnitude. The Isostasy and compaction rates inferred for the last century are also insufficient; they explain less than half of the observed movements. This suggests that the residual — observed rates less Isostasy and compaction estimates — which is interpreted to represent tectonic crustal deformation, constitutes an important contribution to present-day movements. The surprisingly high rates of short-term tectonic vertical movements in a region which is relatively inactive, seismically, indicate that correction of tide-gauge records for the glacio-isostatic signal alone does not yield an appropriate measure of eustatic sea-level rise along the Dutch coast.
S Silenzi - One of the best experts on this subject based on the ideXlab platform.
-
sea level change along the italian coast for the past 10 000 yr
Quaternary Science Reviews, 2004Co-Authors: Kurt Lambeck, Fabrizio Antonioli, Anthony W Purcell, S SilenziAbstract:Relative sea-level change along the Italian coast and adjacent seas—the combined result of eustasy, glacio-hydro-Isostasy and vertical tectonic motion—exhibits considerable spatial and temporal variability throughout the Holocene. The tectonic contribution can be evaluated from the elevation of MIS 5.5 shoreline-markers that are well developed in many localities and the eustatic and isostatic contributions can be predicted from models of ice sheets and earth rheology. Discrepancies between observed Holocene sea levels and model predicted values provide the information for refiningthe model parameters, includingthe tectonic rates of vertical movement. Recent and new Holocene and MIS 5.5 information from 30 sites in Italy has been evaluated and compared with model results to calibrate the predictive model. The resultingparameters for the earth rheology and for the eustatic (ice-volume equivalent) sea-level function are consistent with results from regions outside of the Mediterranean and reflect global values. Using the calibrated model parameters the relative sea-level change due to eustasy and the concomitant Isostasy is predicted across the central Mediterranean region. Holocene tectonic rates of vertical motion are also given for the Italian coastal zone. At most sites where the MIS 5.5 shoreline occurs above or below its ‘tectonically stable’ position, the inferred rates of vertical crustal displacements are consistent with the assumption that average rates for the past B125,000 years are comparable to the average Holocene rates, but at some locations in eastern Sicily and southern Calabria the Holocene rates exceed the longer term average rates. r 2004 Elsevier Ltd. All rights reserved.
-
sea level change along the italian coast for the past 10 000 yr
Quaternary Science Reviews, 2004Co-Authors: Kurt Lambeck, Fabrizio Antonioli, Anthony W Purcell, S SilenziAbstract:Relative sea-level change along the Italian coast and adjacent seas—the combined result of eustasy, glacio-hydro-Isostasy and vertical tectonic motion—exhibits considerable spatial and temporal variability throughout the Holocene. The tectonic contribution can be evaluated from the elevation of MIS 5.5 shoreline-markers that are well developed in many localities and the eustatic and isostatic contributions can be predicted from models of ice sheets and earth rheology. Discrepancies between observed Holocene sea levels and model predicted values provide the information for refiningthe model parameters, includingthe tectonic rates of vertical movement. Recent and new Holocene and MIS 5.5 information from 30 sites in Italy has been evaluated and compared with model results to calibrate the predictive model. The resultingparameters for the earth rheology and for the eustatic (ice-volume equivalent) sea-level function are consistent with results from regions outside of the Mediterranean and reflect global values. Using the calibrated model parameters the relative sea-level change due to eustasy and the concomitant Isostasy is predicted across the central Mediterranean region. Holocene tectonic rates of vertical motion are also given for the Italian coastal zone. At most sites where the MIS 5.5 shoreline occurs above or below its ‘tectonically stable’ position, the inferred rates of vertical crustal displacements are consistent with the assumption that average rates for the past B125,000 years are comparable to the average Holocene rates, but at some locations in eastern Sicily and southern Calabria the Holocene rates exceed the longer term average rates. r 2004 Elsevier Ltd. All rights reserved.
-
coastal deformation between the versilia and the garigliano plains italy since the last interglacial stage
Journal of Quaternary Science, 2003Co-Authors: Marco F Nisi, Fabrizio Antonioli, G Leoni, S SilenziAbstract:The opening of the north-central Tyrrhenian Sea is the result of the Cretaceous- Paleogene alpine collision, which triggered a series of regional uplift, subsidence and transcurrent tectonic mechanisms along the coastal Tyrrhenian sectors of peninsular Italy. These tectonic pro- cesses, in conjunction with the effects of glacio- and hydro-Isostasy during the Quaternary, produced substantial crustal responses that, in some cases, reached metres in extent. In the study of coastal neotectonics, geomorphological markers of the last interglacial maximum, corresponding to marine isotope stage 5.5, are generally used to quantify the magnitude of the vertical crustal displacements that have occurred since 125 kyr. Through altimetrical, palaeoenvironmental and chronological reinterpretation of the most significant works published since 1913, combined with an additional set of data reported here, a detailed reconstruction of the shoreline displacements evident along 500 km of coast between northern Tuscany and southern Latium is presented. The reconstruction was carried out by quantifying the vertical movement since the last interglacial period and by identifying the tectonic behaviour of different coastal sectors. This has been done by carefully choosing the eustatic marker, among those available at each study site, in order to minimize the margin of error associated with the measurements. Copyright 2003 John Wiley & Sons, Ltd.
Anthony W Purcell - One of the best experts on this subject based on the ideXlab platform.
-
the anatomy of interglacial sea levels the relationship between sea levels and ice volumes during the last interglacial
Earth and Planetary Science Letters, 2012Co-Authors: Kurt Lambeck, Anthony W Purcell, Andrea DuttonAbstract:Abstract The elevations and chronology of interglacial shorelines and other sea-level indicators provide information on ice volumes for these earlier periods compared with today. But, as for the Holocene, the relationship between sea levels and ice volumes for earlier interglacials is not simple because of the planet's deformational, gravitational and rotational response to changes in ice-water loads (glacio-hydro Isostasy). In particular, the pattern of global sea level for a particular interglacial will be a function of the earth and ocean response to ice loads applied before, during and after the interglacial in question. This paper examines the role of glacio-hydro Isostasy during these glacial cycles to make three key points. The first is to demonstrate why interglacial sea levels cannot be interpreted directly in terms of ice volume. The second is to illustrate the spatial variability that can be expected in interglacial sea levels because of the Earth's isostatic response to changing ice and water loads and to demonstrate why observations from different localities should not be combined into a single sea-level function without first correcting for differential isostatic effects. The third addresses the question whether, in the absence of perfect knowledge of the ice sheets and earth rheology, inferences can be made about ice volumes during an interglacial. We conclude that if these isostatic factors are ignored, interpretations of interglacial sea levels can lead to serious errors in the inferences about ice volumes during the interglacials.
-
Sea-level history of the Gulf of Mexico since the Last Glacial Maximum with implications for the melting history of the Laurentide Ice Sheet
Quaternary Science Reviews, 2007Co-Authors: Alexander R. Simms, Kurt Lambeck, Anthony W Purcell, John B. Anderson, Antonio B. RodriguezAbstract:Abstract Sea-level records from the Gulf of Mexico at the Last Glacial Maximum, 20 ka, are up to 35 m higher than time-equivalent sea-level records from equatorial regions. The most popular hypothesis for explaining this disparity has been uplift due to the forebulge created by loading from Mississippi River sediments. Using over 50 new radiocarbon dates as well as existing published data obtained from shallow-marine deposits within the northern Gulf of Mexico and numerical models simulating the impact of loading due to the Mississippi Fan and glacio-hydro-Isostasy, we test several possible explanations for this sea-level disparity. We find that neither a large radiocarbon reservoir, sedimentary loading due to the Mississippi Fan, nor large-scale regional uplift can explain this disparity. We do find that with an appropriate model for the Laurentide Ice Sheet, the observations from the Gulf of Mexico can be explained by the process of glacio-hydro-Isostasy. Our analysis suggests that in order to explain this disparity one must consider a Laurentide Ice Sheet reconstruction with less ice from 15 ka to its disappearance 6 ka and more ice from the Last Glacial Maximum to 15 ka than some earlier models have suggested. This supports a Laurentide contribution to meltwater pulse 1-A, which could not have come entirely from its southern sector.
-
sea level change along the italian coast for the past 10 000 yr
Quaternary Science Reviews, 2004Co-Authors: Kurt Lambeck, Fabrizio Antonioli, Anthony W Purcell, S SilenziAbstract:Relative sea-level change along the Italian coast and adjacent seas—the combined result of eustasy, glacio-hydro-Isostasy and vertical tectonic motion—exhibits considerable spatial and temporal variability throughout the Holocene. The tectonic contribution can be evaluated from the elevation of MIS 5.5 shoreline-markers that are well developed in many localities and the eustatic and isostatic contributions can be predicted from models of ice sheets and earth rheology. Discrepancies between observed Holocene sea levels and model predicted values provide the information for refiningthe model parameters, includingthe tectonic rates of vertical movement. Recent and new Holocene and MIS 5.5 information from 30 sites in Italy has been evaluated and compared with model results to calibrate the predictive model. The resultingparameters for the earth rheology and for the eustatic (ice-volume equivalent) sea-level function are consistent with results from regions outside of the Mediterranean and reflect global values. Using the calibrated model parameters the relative sea-level change due to eustasy and the concomitant Isostasy is predicted across the central Mediterranean region. Holocene tectonic rates of vertical motion are also given for the Italian coastal zone. At most sites where the MIS 5.5 shoreline occurs above or below its ‘tectonically stable’ position, the inferred rates of vertical crustal displacements are consistent with the assumption that average rates for the past B125,000 years are comparable to the average Holocene rates, but at some locations in eastern Sicily and southern Calabria the Holocene rates exceed the longer term average rates. r 2004 Elsevier Ltd. All rights reserved.
-
sea level change along the italian coast for the past 10 000 yr
Quaternary Science Reviews, 2004Co-Authors: Kurt Lambeck, Fabrizio Antonioli, Anthony W Purcell, S SilenziAbstract:Relative sea-level change along the Italian coast and adjacent seas—the combined result of eustasy, glacio-hydro-Isostasy and vertical tectonic motion—exhibits considerable spatial and temporal variability throughout the Holocene. The tectonic contribution can be evaluated from the elevation of MIS 5.5 shoreline-markers that are well developed in many localities and the eustatic and isostatic contributions can be predicted from models of ice sheets and earth rheology. Discrepancies between observed Holocene sea levels and model predicted values provide the information for refiningthe model parameters, includingthe tectonic rates of vertical movement. Recent and new Holocene and MIS 5.5 information from 30 sites in Italy has been evaluated and compared with model results to calibrate the predictive model. The resultingparameters for the earth rheology and for the eustatic (ice-volume equivalent) sea-level function are consistent with results from regions outside of the Mediterranean and reflect global values. Using the calibrated model parameters the relative sea-level change due to eustasy and the concomitant Isostasy is predicted across the central Mediterranean region. Holocene tectonic rates of vertical motion are also given for the Italian coastal zone. At most sites where the MIS 5.5 shoreline occurs above or below its ‘tectonically stable’ position, the inferred rates of vertical crustal displacements are consistent with the assumption that average rates for the past B125,000 years are comparable to the average Holocene rates, but at some locations in eastern Sicily and southern Calabria the Holocene rates exceed the longer term average rates. r 2004 Elsevier Ltd. All rights reserved.
Laurence Audin - One of the best experts on this subject based on the ideXlab platform.
-
Role of erosion and Isostasy in the Cordillera Blanca uplift: Insights from landscape evolution modeling (northern Peru, Andes)
Tectonophysics, 2018Co-Authors: Audrey Margirier, Xavier Robert, Jean Braun, Laurence AudinAbstract:Abstract The processes driving uplift and exhumation of the highest Peruvian peaks (the Cordillera Blanca) are not well understood. Uplift and exhumation seem closely linked to the formation and movement on the Cordillera Blanca normal fault (CBNF) that delimits and shapes the western flank of the Cordillera Blanca. Several models have been proposed to explain the presence of this major normal fault in a compressional setting, but the CBNF and the Cordillera Blanca recent rapid uplift remain enigmatic. Whereas the Cordillera Blanca morphology demonstrates important erosion and thus a significant mass of rocks removal, the impact of erosion and Isostasy on the evolution of the Cordillera Blanca uplift rates has never been explored. We address the role of erosion and associated flexural rebound in the uplift and exhumation of the Cordillera Blanca with numerical modeling of landscape evolution. We perform inversions of the broad features of the present-day topography, total exhumation and thermochronological data using a landscape evolution model (FastScape) to provide constraints on the erosion efficiency factor, the uplift rate and the temperature gradient. Our results evidence the not negligible contribution of erosion and associated flexural rebound to the uplift of the Cordillera Blanca and allow us to question the models previously proposed for the formation of the CBNF.
Jean Braun - One of the best experts on this subject based on the ideXlab platform.
-
Role of erosion and Isostasy in the Cordillera Blanca uplift: Insights from landscape evolution modeling (northern Peru, Andes)
Tectonophysics, 2018Co-Authors: Audrey Margirier, Xavier Robert, Jean Braun, Laurence AudinAbstract:Abstract The processes driving uplift and exhumation of the highest Peruvian peaks (the Cordillera Blanca) are not well understood. Uplift and exhumation seem closely linked to the formation and movement on the Cordillera Blanca normal fault (CBNF) that delimits and shapes the western flank of the Cordillera Blanca. Several models have been proposed to explain the presence of this major normal fault in a compressional setting, but the CBNF and the Cordillera Blanca recent rapid uplift remain enigmatic. Whereas the Cordillera Blanca morphology demonstrates important erosion and thus a significant mass of rocks removal, the impact of erosion and Isostasy on the evolution of the Cordillera Blanca uplift rates has never been explored. We address the role of erosion and associated flexural rebound in the uplift and exhumation of the Cordillera Blanca with numerical modeling of landscape evolution. We perform inversions of the broad features of the present-day topography, total exhumation and thermochronological data using a landscape evolution model (FastScape) to provide constraints on the erosion efficiency factor, the uplift rate and the temperature gradient. Our results evidence the not negligible contribution of erosion and associated flexural rebound to the uplift of the Cordillera Blanca and allow us to question the models previously proposed for the formation of the CBNF.
-
modelling landscape evolution on geological time scales a new method based on irregular spatial discretization
Basin Research, 1997Co-Authors: Jean Braun, Malcolm SambridgeAbstract:We present simulations of large-scale landscape evolution on tectonic time scales obtained from a new numerical model which allows for arbitrary spatial discretization. The new method makes use of efficient algorithms from the field of computational geometry to compute the set of natural neighbours of any irregular distribution of points in a plane. The natural neighbours are used to solve geomorphic equations that include erosion/deposition by channelled flow and diffusion. The algorithm has great geometrical flexibility, which makes it possible to solve problems involving complex boundaries, radially symmetrical uplift functions and horizontal tectonic transport across strike-slip faults. The algorithm is also ideally suited for problems which require large variations in spatial discretization and/or self-adaptive meshing. We present a number of examples to illustrate the power of the new approach and its advantages over more ‘classical’ models based on regular (rectangular) discretization. We also demonstrate that the synthetic river networks and landscapes generated by the model obey the laws of network composition and have scaling properties similar to those of natural landscapes. Finally we explain how orographically controlled precipitation and flexural Isostasy may be easily incorporated in the model without sacrificing efficiency.