CIDER 2012 Outcomes
(→Reconciling geophysical and geochemical observations to understand craton lithosphere architecture) |
(→Reconciling geophysical and geochemical observations to understand craton lithosphere architecture) |
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Andrew Lloyd, P. Boehnke, P. Bouilhol, C. Doherty, E. Emry, M. Li, E. Paulson, H. Yue, R. Carlson, D. Wiens, H. Yuan | Andrew Lloyd, P. Boehnke, P. Bouilhol, C. Doherty, E. Emry, M. Li, E. Paulson, H. Yue, R. Carlson, D. Wiens, H. Yuan | ||
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| + | Reconciling geophysical and geochemical observations to understand craton lithospheric lithosphere architecture | ||
| + | The composition of the thick lithospheric mantle beneath cratons is only accessible through geophysical investigation and mantle xenolith records (i.e. lithospheric mantle fragments sampled by volcanoes). How this composition relates to craton formation, evolution and persistence through time remains poorly understood. Geophysical and petrologic observations reveal heterogeneous “layering” in some cratons, while others are less stratified, and apparently do not exhibit internal boundaries. When present, the geophysical characteristics of these different internal structures (e.g. Vs) are partly inherited from the composition of the rocks that form the lithosphere, but also from the dynamic processes by which they form. The xenolith record allows us to tests of whether certain compositions are responsible for the geophysical characteristics. One of the main problems is that it is difficult to know at what time in geological history the layering is acquired, and how it relates in time with craton formation and evolution. Discrepancies arise when there are inconsistencies between the crust and mantle formation ages, as well as between the xenolith age record (i.e. Re-depletion age) within the lithospheric mantle itself. These differences lead to the ultimate question of how and when the lithospheric craton architecture developed, and how it evolved to form stable cratonic roots. Nevertheless, the geophysical and geochemical data cannot always be reconciled, and thus there is not a well established model for the presence or absence of a stratified lithospheric mantle, and how it relates to the formation and evolution of continents through time. Here we take an interdisciplinary approach by bringing together available geophysical and geochemical data aiming to understand the formation and evolution of craton lithospheric lithosphere architecture, and use this these data to test dynamical models of craton formation and destruction. We selected threeThree cratons with available geochemical and seismological data were selected, which differ in structure and chemical composition and may represent cratonic structural end-members. These include the Kaapvaal craton, Slave craton, and North Atlantic craton. By identifying the nature of stratification, we can then reconstruct the viable geodynamic scenarios for its formation and evolution can then be reconstructed. Understanding the nature of the stratified craton and its dynamics of formation is a prerequisite for understanding the survival of such structures and the formation of the earliest continental lithosphere. | ||
==Others== | ==Others== | ||
Revision as of 17:21, 10 August 2012
CIDER 2012 Summer Program Outcomes
2012 AGU Abstrcacts
Reconciling geophysical and geochemical observations to understand craton lithosphere architecture
Andrew Lloyd, P. Boehnke, P. Bouilhol, C. Doherty, E. Emry, M. Li, E. Paulson, H. Yue, R. Carlson, D. Wiens, H. Yuan
Reconciling geophysical and geochemical observations to understand craton lithospheric lithosphere architecture The composition of the thick lithospheric mantle beneath cratons is only accessible through geophysical investigation and mantle xenolith records (i.e. lithospheric mantle fragments sampled by volcanoes). How this composition relates to craton formation, evolution and persistence through time remains poorly understood. Geophysical and petrologic observations reveal heterogeneous “layering” in some cratons, while others are less stratified, and apparently do not exhibit internal boundaries. When present, the geophysical characteristics of these different internal structures (e.g. Vs) are partly inherited from the composition of the rocks that form the lithosphere, but also from the dynamic processes by which they form. The xenolith record allows us to tests of whether certain compositions are responsible for the geophysical characteristics. One of the main problems is that it is difficult to know at what time in geological history the layering is acquired, and how it relates in time with craton formation and evolution. Discrepancies arise when there are inconsistencies between the crust and mantle formation ages, as well as between the xenolith age record (i.e. Re-depletion age) within the lithospheric mantle itself. These differences lead to the ultimate question of how and when the lithospheric craton architecture developed, and how it evolved to form stable cratonic roots. Nevertheless, the geophysical and geochemical data cannot always be reconciled, and thus there is not a well established model for the presence or absence of a stratified lithospheric mantle, and how it relates to the formation and evolution of continents through time. Here we take an interdisciplinary approach by bringing together available geophysical and geochemical data aiming to understand the formation and evolution of craton lithospheric lithosphere architecture, and use this these data to test dynamical models of craton formation and destruction. We selected threeThree cratons with available geochemical and seismological data were selected, which differ in structure and chemical composition and may represent cratonic structural end-members. These include the Kaapvaal craton, Slave craton, and North Atlantic craton. By identifying the nature of stratification, we can then reconstruct the viable geodynamic scenarios for its formation and evolution can then be reconstructed. Understanding the nature of the stratified craton and its dynamics of formation is a prerequisite for understanding the survival of such structures and the formation of the earliest continental lithosphere.
