The fractal analysis of the topography and gravitational field of Venus

Demin, Sergey; Andreev, Alexey; Demina, Natalya; Nefedyev, Yury

doi:10.1088/1742-6596/1038/1/012020

Cited by 9 publications

(2 citation statements)

References 6 publications

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“…The older 245–228 Ma magmatic phase had generated biotite and two-mica granodiorite, monzogranite and leucogranite, which are intruded by the aplitic to pegmatitic muscovite-(tourmaline) leucogranite stocks or dykes (Han, 2008). The younger 225-196 Ma phase is mainly developed in the Mongolian Altay (e.g., the leucogranites in the Chigerte and Sagsai terranes (225 ± 10 Ma), Demin et al. (2001)) and the Russian Altay (e.g., the Triassic leucogranites (Vladimirov et al.…”

Section: Discussionmentioning

confidence: 99%

Petrogenetic and tectonic implications of Triassic granitoids in the Chinese Altay: the Alaer granite example

Liu

Han

2019

Heliyon

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Petrogenesis of the Triassic Alaer granite in the Chinese Altay is important to understand the regional crustal evolution. This study found that the biotite granite is metaluminous and high-K calc-alkaline to shoshonitic. The rocks contain low SiO 2 (64.3–68.7 wt.%), high Al 2 O 3 (13.46–16.56%) and K 2 O (mostly 3.65–7.57 wt.%), and are featured by distinctly higher concentrations of HFSE (e.g., Th, Hf) and ΣREE than those of the nearby Devonian granites. REE patterns show right-inclining trend and weak negative Eu anomalies (δEu = mostly 0.68–0.94), whilst the spidergrams show consistent negative anomalies of Ba, Sr, P, Ti, Nb and Ta and positive anomalies of Th, K, La, Ce, Nd, Zr and Hf. Compared with the local Devonian granites, the Triassic granites have higher calculated initial 87 Sr/ 86 Sr ratios (0.70601–0.70920) and εNd(t) values −(−1.24 to −0.68). Their Nd model ages (average of 1.08 Ga for one-stage and 1.07 Ga for two-stage) are early Neoproterozoic to late Mesoproterozoic. We infer that the Triassic Alaer granite belongs to I-type granite and likely formed in an intraplate extensional setting under high temperature (829–885 °C) and pressure (depths of 30–50 km, corresponding to the middle-lower crust in the Chinese Altay region). Granitic magma was produced through the melting of old continental basement with substantial mantle input, triggered by extensional upwelling of mantle-derived magmas. Mixing equation of Nd isotope compositions yielded a 40% of mantle-derived juvenile components for the Alaer granite petrogenesis.

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Section: Discussionmentioning

confidence: 99%

Petrogenetic and tectonic implications of Triassic granitoids in the Chinese Altay: the Alaer granite example

Liu

Han

2019

Heliyon

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“…For instance, Earth's oceans have calculated fractal dimensions of ≈ 2.3 (Stiassnie 1991; which means that due to surface inhomogeneities Earth's true surface area could be several orders of magnitude greater than what is predicted from a perfect spherical model. Similar analyses have also been performed on the fractal-nature of Mars (Deliège et al 2017;Demin et al 2017) and Venus (Demin et al 2018). Roughness has also been shown to affect the reflective properties of non-fluid surfaces with coarser systems having lower ones than their smoother counterparts (e.g.…”

Section: Our Choice Of Planetmentioning

confidence: 73%

Exploring Super-Earth Surfaces: Albedo of Near-Airless Magma Ocean Planets and Topography

Modirrousta-Galian,

Ito,

Micela

2020

Preprint

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In this paper we propose an analytic function for the spherical albedo values of airless and near-airless magma ocean planets (AMOPs). We generated 2-D fractal surfaces with varying compositions onto which we individually threw 10,000 light rays. Using an approximate form of the Fresnel equations we measured how much of the incident light was reflected. Having repeated this algorithm on varying surface roughnesses we find the spherical albedo as a function of the Hurst exponent, the geochemical composition of the magma, and the wavelength. As a proof of concept, we used our model on Kepler-10b to demonstrate the applicability of our approach. We present the spherical albedo values produced from different lava compositions and multiple tests that can be applied to observational data in order to determine their characteristics. Currently, there is a strong degeneracy in the surface composition of AMOPs due to the large uncertainties in their measured spherical albedos. In spite of this, when applied to Kepler-10b we show that its high albedo could be caused by a moderately wavy ocean that is rich in oxidised metallic species such as FeO, Fe 2 O 3 , Fe 3 O 4 . This would imply that Kepler-10b is a coreless or near-coreless body.

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Exploring super-Earth surfaces: Albedo of near-airless magma ocean planets and topography

Modirrousta-Galian

Itō

Micela

2021

Icarus

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The fractal analysis of the topography and gravitational field of Venus

Cited by 9 publications

References 6 publications

Petrogenetic and tectonic implications of Triassic granitoids in the Chinese Altay: the Alaer granite example

Petrogenetic and tectonic implications of Triassic granitoids in the Chinese Altay: the Alaer granite example

Exploring Super-Earth Surfaces: Albedo of Near-Airless Magma Ocean Planets and Topography

Exploring super-Earth surfaces: Albedo of near-airless magma ocean planets and topography

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