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Nicolas Coltice

Bio: Nicolas Coltice is an academic researcher from École Normale Supérieure. The author has contributed to research in topics: Mantle (geology) & Mantle convection. The author has an hindex of 30, co-authored 66 publications receiving 3083 citations. Previous affiliations of Nicolas Coltice include University of Lyon & Institut Universitaire de France.


Papers
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Journal ArticleDOI
06 Dec 2007-Nature
TL;DR: It is shown that a stable layer of dense melt formed at the base of the mantle early in the Earth’s history would have undergone slow fractional crystallization, and would be an ideal candidate for an unsampled geochemical reservoir hosting a variety of incompatible species for an initial basal magma ocean thickness of about 1,000 km.
Abstract: If a stable layer of dense melt formed at the base of the mantle early in Earth's history, it would have undergone slow fractional crystallization and could provide an unsampled geochemical reservoir hosting a variety of incompatible geochemical species (most notably the missing budget of heat producing elements). The distribution of geochemical species in the Earth’s interior is largely controlled by fractional melting and crystallization processes that are intimately linked to the thermal state and evolution of the mantle. The existence of patches of dense partial melt at the base of the Earth’s mantle1, together with estimates of melting temperatures for deep mantle phases2 and the amount of cooling of the underlying core required to maintain a geodynamo throughout much of the Earth’s history3, suggest that more extensive deep melting occurred in the past. Here we show that a stable layer of dense melt formed at the base of the mantle early in the Earth’s history would have undergone slow fractional crystallization, and would be an ideal candidate for an unsampled geochemical reservoir hosting a variety of incompatible species (most notably the missing budget of heat-producing elements) for an initial basal magma ocean thickness of about 1,000 km. Differences in 142Nd/144Nd ratios between chondrites and terrestrial rocks4 can be explained by fractional crystallization with a decay timescale of the order of 1 Gyr. These combined constraints yield thermal evolution models in which radiogenic heat production and latent heat exchange prevent early cooling of the core and possibly delay the onset of the geodynamo to 3.4–4 Gyr ago5.

677 citations

Journal ArticleDOI
01 May 2007-Geology
TL;DR: The authors showed that continental aggregation promotes large-scale melting without requiring the involvement of plumes, when only internal heat sources in the mantle are considered, and that the formation of a supercontinent causes the enlargement of flow wavelength and a subcontinental increase in temperature as large as 100 °C.
Abstract: Continents episodically cluster together into a supercontinent, eventually breaking up with intense magmatic activity supposedly caused by mantle plumes ([Morgan, 1983][1]; [Richards et al., 1989][2]; [Condie, 2004][3]). The breakup of Pangea, the last supercontinent, was accompanied by the emplacement of the largest known continental flood basalt, the Central Atlantic Magmatic Province, which caused massive extinctions at the Triassic-Jurassic boundary ([Marzoli et al., 1999][4]). However, there is little support for a plume origin for this catastrophic event ([McHone, 2000][5]). On the basis of convection modeling in an internally heated mantle, this paper shows that continental aggregation promotes large-scale melting without requiring the involvement of plumes. When only internal heat sources in the mantle are considered, the formation of a supercontinent causes the enlargement of flow wavelength and a subcontinental increase in temperature as large as 100 °C. This temperature increase may lead to large-scale melting without the involvement of plumes. Our results suggest the existence of two distinct types of continental flood basalts, caused by plume or by mantle global warming. [1]: #ref-21 [2]: #ref-26 [3]: #ref-5 [4]: #ref-17 [5]: #ref-19

223 citations

Journal ArticleDOI
TL;DR: Rey et al. as discussed by the authors investigated the continental freeboard predicted using different models for the cooling of the Earth and showed that constancy of the freeboard is possible throughout the history of the planet as long as the potential temperature of the upper mantle was never more than 110−210°C hotter than present.

189 citations

Journal ArticleDOI
TL;DR: Coltice et al. as discussed by the authors used 3D numerical simulations of mantle convection to show that the mantle global warming model could explain the peculiarities of magmatic provinces that developed during the formation of Pangea and Rodinia, as well as putative Archaean supercontinents such as Kenorland and Zimvaalbara.

158 citations

Journal ArticleDOI
TL;DR: In this article, a time dependent model with five reservoirs (bulk mantle, continental crust, atmosphere, residual deep mantle and DQ) is studied for Rb/ Sr and U/Pb/He systems.

147 citations


Cited by
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01 Apr 2003
TL;DR: The EnKF has a large user group, and numerous publications have discussed applications and theoretical aspects of it as mentioned in this paper, and also presents new ideas and alternative interpretations which further explain the success of the EnkF.
Abstract: The purpose of this paper is to provide a comprehensive presentation and interpretation of the Ensemble Kalman Filter (EnKF) and its numerical implementation. The EnKF has a large user group, and numerous publications have discussed applications and theoretical aspects of it. This paper reviews the important results from these studies and also presents new ideas and alternative interpretations which further explain the success of the EnKF. In addition to providing the theoretical framework needed for using the EnKF, there is also a focus on the algorithmic formulation and optimal numerical implementation. A program listing is given for some of the key subroutines. The paper also touches upon specific issues such as the use of nonlinear measurements, in situ profiles of temperature and salinity, and data which are available with high frequency in time. An ensemble based optimal interpolation (EnOI) scheme is presented as a cost-effective approach which may serve as an alternative to the EnKF in some applications. A fairly extensive discussion is devoted to the use of time correlated model errors and the estimation of model bias.

2,975 citations

Journal Article
TL;DR: In this article, a digital age grid of the ocean floor with a grid node interval of 6 arc min using a self-consistent set of global isochrons and associated plate reconstruction poles was created.
Abstract: We have created a digital age grid of the ocean floor with a grid node interval of 6 arc min using a self-consistent set of global isochrons and associated plate reconstruction poles. The age at each grid node was determined by linear interpolation between adjacent isochrons in the direction of spreading. Ages for ocean floor between the oldest identified magnetic anomalies and continental crust were interpolated by estimating the ages of passive continental margin segments from geological data and published plate models. We have constructed an age grid with error estimates for each grid cell as a function of (1) the error of ocean floor ages identified from magnetic anomalies along ship tracks and the age of the corresponding grid cells in our age grid, (2) the distance of a given grid cell to the nearest magnetic anomaly identification, and (3) the gradient of the age grid: i.e., larger errors are associated with high age gradients at fracture zones or other age discontinuities. Future applications of this digital grid include studies of the thermal and elastic structure of the lithosphere, the heat loss of the Earth, ridge-push forces through time, asymmetry of spreading, and providing constraints for seismic tomography and mantle convection models.

752 citations

Journal ArticleDOI
TL;DR: This paper presented a revised global plate motion model with continuously closing plate boundaries ranging from the Triassic at 230 Ma to the present day, assess differences among alternative absolute plate motion models, and review global tectonic events.
Abstract: We present a revised global plate motion model with continuously closing plate boundaries ranging from the Triassic at 230 Ma to the present day, assess differences among alternative absolute plate motion models, and review global tectonic events. Relatively high mean absolute plate motion rates of approximately 9–10 cm yr^(−1) between 140 and 120 Ma may be related to transient plate motion accelerations driven by the successive emplacement of a sequence of large igneous provinces during that time. An event at ∼100 Ma is most clearly expressed in the Indian Ocean and may reflect the initiation of Andean-style subduction along southern continental Eurasia, whereas an acceleration at ∼80 Ma of mean rates from 6 to 8 cm yr^(−1) reflects the initial northward acceleration of India and simultaneous speedups of plates in the Pacific. An event at ∼50 Ma expressed in relative, and some absolute, plate motion changes around the globe and in a reduction of global mean plate speeds from about 6 to 4–5 cm yr^(−1) indicates that an increase in collisional forces (such as the India–Eurasia collision) and ridge subduction events in the Pacific (such as the Izanagi–Pacific Ridge) play a significant role in modulating plate velocities.

723 citations

Book ChapterDOI
TL;DR: Hofmann et al. as discussed by the authors reviewed the recent advances in the field of mantle geology, geophysics, and geochemistry using seismic mantle tomography, and concluded that the established views of the mantle being engaged in simple two-or single-layer convection are becoming obsolete.
Abstract: This chapter is in part an update of a previous, more abbreviated review ( Hofmann, 1997 ) It covers the subject in greater depth, and it reflects some significant changes in the author's views since the writing of the earlier paper In particular, the spatial range of equilibrium attained during partial melting may be much smaller than previously thought, because of new experimental diffusion data and new results from natural settings Also, the question of ‘layered’ versus ‘whole-mantle’ convection, including the depth of subduction and of the origin of plumes, has to be reassessed in light of the recent breakthroughs achieved by seismic mantle tomography As the spatial resolution of seismic tomography and the pressure range, accuracy, and precision of experimental data on melting relations, phase transformations, and kinetics continue to improve, the interaction between these disciplines and geochemistry sensu stricto will continue to improve our understanding of what is actually going on in the mantle The established views of the mantle being engaged in simple two- or single-layer convection are becoming obsolete In many ways, we are just at the beginning of this new phase of mantle geology, geophysics, and geochemistry

701 citations

Journal ArticleDOI
TL;DR: In this paper, a revised definition of large Igneous provinces (LIPs) is proposed, which is based on the definition of LIP events from other melting events of the upper mantle, and reassess and revise how we define LIPs.

698 citations