scholarly journals Radiative thermal conductivity of single-crystal bridgmanite at the core-mantle boundary with implications for thermal evolution of the Earth

2022 ◽  
Vol 578 ◽  
pp. 117329
Author(s):  
Motohiko Murakami ◽  
Alexander F. Goncharov ◽  
Nobuyoshi Miyajima ◽  
Daisuke Yamazaki ◽  
Nicholas Holtgrewe
1979 ◽  
Vol 82 ◽  
pp. 55-57
Author(s):  
L. V. Morrison

Observations of the Earth's rotation have shown irregular variations of rate which have characteristic times of decades. These have been attributed to transfer of angular momentum between core and mantle by some mechanism such as inertial coupling, viscous stress, electromagnetic coupling or stresses produced by topographic features on the core mantle boundary.


2012 ◽  
Vol 349-350 ◽  
pp. 109-115 ◽  
Author(s):  
Kenji Ohta ◽  
Takashi Yagi ◽  
Naoyuki Taketoshi ◽  
Kei Hirose ◽  
Tetsuya Komabayashi ◽  
...  

2020 ◽  
Author(s):  
Mioara Mandea ◽  
Veronique Dehant ◽  
Anny Cazenave

<div> <p>To understand the processes involved in the deep interior of the Earth and explaining its evolution, in particular the dynamics of the Earth’s fluid iron-rich outer core, only indirect satellite and ground observations are available. They each provide invaluable information about the core flow but are incomplete on their own:</p> <p>-        The time dependent magnetic field, originating mainly within the core, can be used to infer the motions of the fluid at the top of the core on decadal and subdecadal time scales.</p> <p>-        The time dependent gravity field variations that reflect changes in the mass distribution within the Earth and at its surface occur on a broad range of time scales. Decadal and interannual variations include the signature of the flow inside the core, though they are largely dominated by surface contributions related to the global water cycle and climate-driven land ice loss.</p> <p>-        Earth rotation changes (or variations in the length of the day) also occur on these time scales, and are largely related to the core fluid motions through exchange of angular momentum between the core and the mantle at the core-mantle boundary.</p> <p>Here, we present the main activities proposed in the frame of the GRACEFUL ERC project, which aims to combine information about the core deduced from the gravity field, from the magnetic field and from the Earth rotation in synergy, in order to examine in unprecedented depth the dynamical processes occurring inside the core and at the core-mantle boundary.</p> </div>


1990 ◽  
Vol 141 ◽  
pp. 161-162
Author(s):  
V. V. Bykova

The nutation of the Earth with slightly nonelliptical liquid core is investigated by the perturbation theory method. It is shown that first-order terms affect the core ellipticity and its triaxiality. The most sensitive nutation terms in the second approximation were found to be retrograde 18.6-year term and retrograde annual term. The observed nutation amplitude values can be satisfied by special core-mantle boundary form.


1988 ◽  
Vol 129 ◽  
pp. 377-377
Author(s):  
Bradford H. Hager

The core-mantle boundary (CMB), separating the molten metallic core from the overlying solid silicate mantle, marks the largest discontinuity in mechanical properties within the Earth. The ∼ 200 km thick region just above the CMB, named D″ by Bullen (1950), is characterized by an anomalous gradient in seismic velocity versus depth. D″ was originally interpreted as a region with a strong compositional gradient due to the accumulation of dense material at the base of the mantle. Subsequently, the anomalous gradient was interpreted as the result of a strong temperature gradient in a hot thermal boundary layer at the base of the mantle, an interpretation motivated by the requiremnet that heat involved in generating the geodynamo must be transported out of the core and through the mantle by convection.


2020 ◽  
Vol 12 (24) ◽  
pp. 4186
Author(s):  
Mioara Mandea ◽  
Véronique Dehant ◽  
Anny Cazenave

While the main causes of the temporal gravity variations observed by the Gravity Recovery and Climate Experiment (GRACE) space mission result from water mass redistributions occurring at the surface of the Earth in response to climatic and anthropogenic forces (e.g., changes in land hydrology, ocean mass, and mass of glaciers and ice sheets), solid Earth’s mass redistributions were also recorded by these observations. This is the case, in particular, for the glacial isostatic adjustment (GIA) or the viscous response of the mantle to the last deglaciation. However, it has only recently been shown that the gravity data also contain the signature of flows inside the outer core and their effects on the core–mantle boundary (CMB). Detecting deep Earth’s processes in GRACE observations offers an exciting opportunity to provide additional insight into the dynamics of the core–mantle interface. Here, we present one aspect of the GRACEFUL (GRavimetry, mAgnetism and CorE Flow) project, i.e., the possibility to use gravity field data for understanding the dynamic processes inside the fluid core and core–mantle boundary of the Earth, beside that offered by the geomagnetic field variations.


Science ◽  
1997 ◽  
Vol 275 (5306) ◽  
pp. 1623-1625 ◽  
Author(s):  
K. G. Holland ◽  
T. J. Ahrens

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