Density structure of the lithospheric mantle: upscaling from minerals to peridotites

2021 ◽  
Author(s):  
Luca Faccincani ◽  
Barbara Faccini ◽  
Federico Casetta ◽  
Maurizio Mazzucchelli ◽  
Fabrizio Nestola ◽  
...  
Keyword(s):  
Elastic Properties ◽  
Lithospheric Mantle ◽  
Equations Of State ◽  
Thermal State ◽  
Bulk Composition ◽  
Chemical Compositions ◽  
Density Structure ◽  
Earth Planet ◽  
Mantle Peridotites ◽  
Geodynamic Processes

<p>The knowledge of the density structure of the lithospheric mantle is critical to our comprehension of tectonic and magmatic events occurring within the lithosphere and crucial to model the evolution of complex geodynamic processes (e.g., subduction dynamics, mantle plume upwelling etc). Furthermore, a thorough understanding of the density evolution at mantle conditions is essential to interpret geophysical data such as seismic tomography (e.g., Afonso et al., 2008; Stixrude and Lithgow-Bertelloni, 2012).</p><p>The density of mantle peridotites is related to chemical composition, modal abundance and elastic properties of their constituent minerals, which in turn are controlled by pressure, temperature and bulk composition of the system. Accordingly, the elastic properties of mantle minerals combined with the thermal state of the lithosphere can predict how the physical properties (e.g., density, elastic <em>moduli</em>) of mantle peridotites vary with depth. To this aim, (i) we examined the existing literature data (compressibility, thermal expansion and elasticity) suitable to constrain the elastic properties of peridotite minerals and (ii) we addressed the density structure of two potential lithospheric mantle sections (fertile and depleted) across different thermal regimes from the perspective of the Equations of State (EoS) of their constituent minerals.</p><p>In a mantle characterized by a relatively cold geotherm (45 mWm<sup>-2</sup>), the density of a depleted peridotitic system remains nearly constant up to about 4 GPa, while it moderately increases in a fertile system. In a mantle characterized by a relatively hot geotherm (60 mWm<sup>-2</sup>), the density of both depleted and fertile systems decreases up to about 3 GPa, due to the more rapid raise of temperature compared to pressure, and then it increases downwards.</p><p>These preliminary results show that the thermal state of the lithosphere produces a first-order signature in its density structure, with few differences owing to different modes and crystal chemical compositions.</p><p><strong>References</strong></p><p>Afonso, J.C., Fernàndez, M., Ranalli, G., Griffin, W.L., Connolly, J.A.D., 2008. Integrated geophysical-petrological modeling of the lithosphere and sublithospheric upper mantle: Methodology and applications. Geochemistry, Geophys. Geosystems 9, Q05008.</p><p>Stixrude, L., Lithgow-Bertelloni, C., 2012. Geophysics of Chemical Heterogeneity in the Mantle. Annu. Rev. Earth Planet. Sci. 40, 569–595.</p>

Carbon-rich composition of the icy moons of Jupiter and Saturn, and asteroid 1-Ceres

2020 ◽  
Author(s):  
Bruno Reynard ◽  
Adrien Neri ◽  
François Guyot ◽  
Christophe Sotin
Keyword(s):  
Building Materials ◽  
Equations Of State ◽  
Thermal Evolution ◽  
Bulk Composition ◽  
Metal Sulfide ◽  
Carbonaceous Matter ◽  
Earth Planet ◽  
Icy Moons ◽  
Compositional Model ◽  
Insoluble Organic Matter

<p>The inner structure of icy moons comprises ices, liquid water, a silicate rocky core and sometimes an inner metallic core depending on thermal evolution and differentiation. Mineralogy and density models for the silicate part of the icy satellites cores were assessed assuming a carbonaceous chondritic (CI) bulk composition and using a free-energy minimization code and experiments [1]. Densities of other components, solid and liquid sulfides, carbonaceous matter, were evaluated from available equations of state. Model densities for silicates are larger than assessed from magnesian terrestrial minerals, by 200 to 600 kg/m<sup>3</sup> for the hydrated silicates, and 300 to 500 kg/m<sup>3</sup> for the dry silicates, due to the lower iron bulk concentration in terrestrial silicates as a lot of iron is segregated in the core.</p><p>We find that CI density models of icy satellite cores taking into account only the silicate and metal/sulfide fraction cannot account for the observed densities and reduced moment of inertia of Titan and Ganymede without adding a lower density component. We propose that this low-density component is carbonaceous matter derived from insoluble organic matter, in proportion of ~30-40% in volume and 15-20% in mass. This proportion is compatible with contributions from CI and comets, making these primitive bodies including their carbonaceous matter component likely precursors of icy moons, and potentially of most of the objects formed behind the snow line of the solar system. Similar conclusions are reached for 1-Ceres when applying this compositional model, with even higher carbon content of the order of 25±5wt% in line with independent estimates [2]. It suggests that the building materials are similar for asteroid 1-Ceres and the icy moons of giant planets.</p><p> </p><p>[1]Neri et al., Earth Planet Sci Letters, 530 (2020) 115920</p><p>[2]Zolotov, Icarus, 335 (2020) 113404</p>

Density model of the Permo – Triassic lithospheric mantle of the Ivrea Verbano Complex

2021 ◽  
Author(s):  
Luca Faccincani ◽  
Federico Casetta ◽  
Barbara Faccini ◽  
Maurizio Mazzucchelli ◽  
Fabrizio Nestola ◽  
...  
Keyword(s):  
Lithospheric Mantle ◽  
Equations Of State ◽  
Mantle Peridotite ◽  
Radiometric Dating ◽  
Variscan Orogeny ◽  
Spinel Lherzolite ◽  
Density Structure ◽  
Holistic View ◽  
Melt Extraction ◽  
Mafic Complex

<p>The Ivrea – Verbano Zone (IVZ) is a virtually complete lower-to-middle continental crustal section exposed in the Western Italian Alps in result of exhumation processes during the Alpine orogenic cycle. To the northwest, the IVZ is juxtaposed to the basement of the Austro-Alpine Domain by the lnsubric Line; to the southeast, it is separated from the middle-to-upper crustal levels of the Strona – Ceneri Zone by the Pogallo and the Cossato-Mergozzo-Brissago (CMB) lines. The IVZ crustal section is constituted by two main units: the Kinzigite Formation, amphibolite- to granulite-facies sedimentary and igneous metamorphic rocks, and the Mafic Complex, a thick, composite gabbroid-to-dioritic intrusion.</p><p>Additionally, the lower crustal rocks of IVZ embed a series of kilometre-scale peridotite bodies; Baldissero, Balmuccia and Finero are the most relevant. These peridotites are thought to represent remnants of the oldest portion of subcontinental lithospheric mantle (SCLM) beneath Europe. Geochemical and isotopic studies indicate that peridotitic bodies experienced an Upper Devonian partial melting event followed by protracted enrichments while resident in the mantle. Field and structural relationships coupled with radiometric dating suggest that the emplacement of the mantle peridotite bodies at crustal levels has occurred since the end of the Variscan orogeny, prior to the intrusion of the Mafic Complex.</p><p>The Balmuccia Massif is dominated by fresh spinel lherzolites recording moderate degrees of melt extraction, subordinated harzburgites, reactive dunites and diffuse cross-cutting websteritic dykes. The melt extraction and melt-fluid/rock-reactions preserved in the Balmuccia peridotite, together with the lack of substantial low-temperature alteration, enable to track the evolution of the SCLM prior to its uplift and emplacement in crust. Therefore, reconstructing the density structure of the Balmuccia body could have major implications on the comprehension of the geodynamic evolution of the oldest portions of the European lithospheric mantle.</p><p>In this study, we modelled the density structure of the spinel lherzolite from the Balmuccia Massif, starting from the chemical composition and modal abundance of its main phase constituents. It is well known that the bulk density is function of modes, compositions and elastic properties of constituent minerals and can be explored from the perspective of their Equations of State (EoS) (see also Faccincani et al., 2021, abstract to session GD7.3 for a more holistic view of the density structure of the lithospheric mantle). By assuming that the EoS for a polyphase aggregate (e.g., a rock) may be calculated as weighted mean of the EoS of the constituting minerals (in our case olivine, orthopyroxene, clinopyroxene, spinel and garnet at increasing depths), we investigated the density structure of a virtual 1-D vertical profile of the lithospheric mantle below the IVZ at pre-Variscan ages.</p>

Non-Newtonian effects in axially symmetric oscillatory flows of some elastico-viscous liquids

1970 ◽  
Vol 68 (3) ◽  
pp. 731-750 ◽  
Author(s):  
J. R. Jones
Keyword(s):  
Elastic Properties ◽  
Equations Of State ◽  
Time Lag ◽  
Physical Constant ◽  
Oscillatory Motion ◽  
Axially Symmetric ◽  
Metric Tensor ◽  
Oscillatory Flows ◽  
Viscous Liquids ◽  
Deformation Stress

In (general) elastico-viscous liquids the response to stress at any instant will depend on previous rheological history, the equations of state needed to describe the rheological properties of a typical material element at any instant t being expressible in the form of a (properly invariant†) set of integro-differential equations relating its deformation, stress and temperature histories (as defined by a metric tensor (of a convected frame of reference), a stress tensor and the temperature measured in the element as functions of previous time t'( < t)) together with the time lag (t – t') and physical constant tensors associated with the element (1). Thus in any type of oscillatory motion a rheological history will necessarily be a function of the frequency of the forcing agent, the rheological history of a number of different types of elastico-viscous liquids in some simple shearing oscillatory flows being a rather simple oscillatory history (see, for example, (2–4)). It is, therefore, to be expected that a liquid with elastic properties will behave somewhat differently from any inelastic viscous liquid when subjected to any kind of oscillatory motion, and it is for this reason that oscillatory motions have been used extensively to detect and measure the elastic properties of liquids (see, for example, (2–5)).

scholarly journals The density–salinity relation of standard seawater

Ocean Science ◽  
2018 ◽  
Vol 14 (1) ◽  
pp. 15-40 ◽  
Author(s):  
Hannes Schmidt ◽  
Steffen Seitz ◽  
Egon Hassel ◽  
Henning Wolf
Keyword(s):  
North Atlantic ◽  
Equations Of State ◽  
North Atlantic Ocean ◽  
Density Measurement ◽  
Chemical Compositions ◽  
Target Uncertainty ◽  
Density Measurements ◽  
The North ◽  
Reference Equations ◽  
The North Atlantic

Abstract. The determination of salinity by means of electrical conductivity relies on stable salt proportions in the North Atlantic Ocean, because standard seawater, which is required for salinometer calibration, is produced from water of the North Atlantic. To verify the long-term stability of the standard seawater composition, it was proposed to perform measurements of the standard seawater density. Since the density is sensitive to all salt components, a density measurement can detect any change in the composition. A conversion of the density values to salinity can be performed by means of a density–salinity relation. To use such a relation with a target uncertainty in salinity comparable to that in salinity obtained from conductivity measurements, a density measurement with an uncertainty of 2 g m−3 is mandatory. We present a new density–salinity relation based on such accurate density measurements. The substitution measurement method used is described and density corrections for uniform isotopic and chemical compositions are reported. The comparison of densities calculated using the new relation with those calculated using the present reference equations of state TEOS-10 suggests that the density accuracy of TEOS-10 (as well as that of EOS-80) has been overestimated, as the accuracy of some of its underlying density measurements had been overestimated. The new density–salinity relation may be used to verify the stable composition of standard seawater by means of routine density measurements.

Zoned olivine xenocrysts in a late Mesozoic gabbro from the southern Taihang Mountains: implications for old lithospheric mantle beneath the central North China Craton

2009 ◽  
Vol 147 (2) ◽  
pp. 161-170 ◽  
Author(s):  
JI-FENG YING ◽  
HONG-FU ZHANG ◽  
YAN-JIE TANG
Keyword(s):  
North China Craton ◽  
Lithospheric Mantle ◽  
Large Scale ◽  
North China ◽  
Eastern China ◽  
Late Mesozoic ◽  
Mantle Peridotites

AbstractZoned olivine grains are abundant in the late Mesozoic Shatuo gabbro (southern Taihang Mountains, central North China Craton). Olivine cores are rich in MgO and NiO, rims are rich in FeO and MnO, and both cores and rims have very low CaO contents. The cores invariably have a high Mg no. (92–94), similar to olivine xenocrysts from Palaeozoic kimberlites in eastern China. The compositional features of these olivines imply that they are xenocrysts rather than phenocrysts, namely, disaggregates of mantle peridotites at the time of intrusion. The compositional similarity of olivine cores to xenocrysts from Palaeozoic kimberlites suggests that the lithospheric mantle beneath the central North China Craton is ancient and refractory in nature, and quite different from eastern China, where the mantle is mainly composed of newly accreted materials resulting from large-scale lithospheric removal and replacement. The contrasting features of the lithospheric mantle beneath the eastern and central North China Craton imply that the large-scale lithospheric removal in Phanerozoic times was mainly confined to the eastern North China Craton.

Thermal state and composition of the lithospheric mantle beneath the Daldyn kimberlite field, Yakutia

1996 ◽  
Vol 262 (1-4) ◽  
pp. 19-33 ◽  
Author(s):  
W.L. Griffin ◽  
F.V. Kaminsky ◽  
C.G. Ryan ◽  
S.Y. O'Reilly ◽  
T.T. Win ◽  
...  
Keyword(s):  
Lithospheric Mantle ◽  
Thermal State ◽  
Kimberlite Field

Nondestructive Characterization of Beryllium Effects on Ni-Cr Dental Alloy Elastic Properties and Microstructure: Ultrasonics, X-Ray Diffractometry, Scanning Electron Microscopy and Wavelength Dispersive Spectrometry

1988 ◽  
Vol 142 ◽  
Author(s):  
Surendra Singh ◽  
J. Lawrence Katz ◽  
B. S. Rosenblatt
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Elastic Properties ◽  
Ultrasonic Pulse ◽  
Chemical Compositions ◽  
Transmission Method ◽  
Buoyant Force ◽  
X Ray ◽  
Wavelength Dispersive Spectrometry ◽  
Scanning Electron

AbstractKnowledge of structure-properties relationship is a key factor in the development and improvement of new and existing metal alloys through manipulation in their chemical-compositions. In this study, the elastic properties and microstructure of cast Ni-Cr-Be and Ni-Cr dental alloys were studied. The elastic properties, i.e., Young's, shear and bulk moduli and Poisson's ratios, were determined using measurements on the ultrasonic velocities and densities. Both the shear and the longitudinal (dilatational) velocities were measured using an ultrasonic pulse-through-transmission method; density was measured using a buoyant force method. In microstructure, crystallinity, porosity, particle-size and quantitative elemental compositions were studied using x-ray diffractometry (XRD), scanning electron microscopy (SEM) and wavelength dispersive spectrometry (WDS) respectively. These results show that: (1) the addition of Be increased significantly the alloy's elastic moduli and Poisson's ratio; and (2) the presence of Be in Ni-Cr alloy also significantly modified its microstructure by producing a second binary phase, Ni-Be, in eutectic areas.

EoS of mantle minerals coupled with composition and thermal state of the lithosphere: Inferring the density structure of peridotitic systems

Lithos ◽  
2021 ◽  
pp. 106483
Author(s):  
Luca Faccincani ◽  
Barbara Faccini ◽  
Federico Casetta ◽  
Maurizio Mazzucchelli ◽  
Fabrizio Nestola ◽  
...  
Keyword(s):  
Thermal State ◽  
Density Structure ◽  
Mantle Minerals

Eclogite and garnet pyroxenite xenoliths from kimberlite pipes of north Siberian craton - evidences of subduction processes and cumulate origin

2021 ◽  
Author(s):  
Tatiana Kalashnikova ◽  
Lidia Solov'eva ◽  
Sergey Kostrovitsky ◽  
Konstantin Sinitsyn ◽  
Elvira Yudintseva
Keyword(s):  
Mineral Composition ◽  
Siberian Craton ◽  
Lithospheric Mantle ◽  
Isotope Composition ◽  
Bulk Composition ◽  
Mantle Xenoliths ◽  
Rock Composition ◽  
Geochemical Properties ◽  
Eu Anomaly ◽  
Wide Range

&lt;p&gt;The lithospheric mantle structure and evolution is one of the fundamental problems of the Earth's history. Eclogites and clinopyroxenite xenoliths are characterized by a similar two-mineral composition (garnet and clinopyroxene), but differ in mineralogical and petrographic features (Gonzaga et al., 2010). Questions of their origin and relationship with peridotites remain controversial. There are several classifications of eclogites based on various attributes: structural and textural features (Mercier &amp; Nicolas, 1975; MacGregor &amp; Carter, 1970), chemical composition of garnet (Coleman, 1965), clinopyroxene (Taylor &amp; Neal, 1989), as well as the whole rock composition (Aulbach et al., 2016 and other), the given classifications may not coincide. The geochemical properties of eclogite xenoliths from kimberlite pipes suggest two main points of view for genesis: implication of subduction processes or cumulates of high-pressure melting in lithosphere mantle (Condie, 1993; Jacob et al., 1994). The &quot;classical&quot; cratonic eclogites represent an ancient oceanic crust subsequently subducted and altered possible further metasomatic processes. These rocks are characterized by significant variations in the composition of minerals, a relatively high content of Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; (14-20 wt%) and a low MgO content (10-15 wt%), depletion of elements of the LREE and an Eu anomaly (Gonzaga et al., 2010). In addition, eclogites have a wide range of oxygen isotopic composition in garnet &amp;#948;&lt;sup&gt;18&lt;/sup&gt;O 4.51 - 8.69 (much higher than mantle values &amp;#8203;&amp;#8203;5.3 &amp;#177; 0.3) (9). Garnet pyroxenites are characterized by a more magnesian garnet - pyrope and bulk composition (MgO - 15-20 wt.%). The oxygen isotope composition of Grt from clinopyroxenites is close to that of the mantle - &amp;#948;&lt;sup&gt;18&lt;/sup&gt;O 5.2 - 5.8. It is assumed that these rocks are a consequence of the polybaric partial melting at high temperatures and pressures (Gonzaga et al., 2010). The mantle xenoliths from upper-Jurassic Obnajennaya kimberlite pipe (Kuoika field, Yakutia) were studied. Eclogites and clinopyroxenites occupy about 10-15% population among xenoliths. Garnet in the eclogites differs from that in the clinopyroxenites by a higher content of CaO and FeO (Prp&lt;sub&gt;55-62 &lt;/sub&gt;Alm&lt;sub&gt;22-30&lt;/sub&gt;Grs&lt;sub&gt;8-18 &lt;/sub&gt;in clinopyroxenites and Prp&lt;sub&gt;40-45&lt;/sub&gt;Alm&lt;sub&gt;13-29&lt;/sub&gt;Grs&lt;sub&gt;15-30 &lt;/sub&gt;in eclogites). Clinopyroxenes are distinguished by reduced magnesia content (Mg# 91-84), as well as low calcium content (16-18 wt.%). The high contents of jadeite components in the clinopyroxene (NaAl[Si&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;6&lt;/sub&gt;] - 25-32%) classify this group of rocks as eclogites. The high &amp;#948;&lt;sup&gt;18&lt;/sup&gt;O varies in eclogite Cpx (more than 6.0), positive Eu anomaly is assumed that the formation of the protolith of the xenolith group occurred as melts in the subduction zone during accretion of the Birekte block to the Siberian craton (Rosen, 2003). However, the presence of garnet clinopyroxenites with narrow variations in mineral composition and relatively low &amp;#948;&lt;sup&gt;18&lt;/sup&gt;O suggests melting processes in the lithospheric mantle and the formation of megacrystalline pyroxene cumulates.&lt;/p&gt;&lt;p&gt;The research was supported by Russian Science Foundation grant &amp;#8470;20-77-00074.&lt;/p&gt;

Sign in / Sign up

Export Citation Format

Share Document