The viscosity of magma plays a crucial role in the dynamics of the Earth: from the crystallization of a magma ocean during its initial stages to modern-day volcanic processes. However, the pressure-dependence behavior of viscosity at high pressure remains controversial. In this study, we report the results of first-principles molecular dynamics simulations of basaltic melt to show that the melt viscosity increases upon compression along each isotherm for the entire lower mantle after showing minima at ~6 GPa. However, elevated temperatures of the magma ocean translate to a narrow range of viscosity, i.e., 0.01-0.03 Pa.s. This low viscosity implies that the crystallization of the magma ocean could be complete within a few million years. These results also suggest that the crystallization of the magma ocean is likely to be fractional, thus supporting the hypothesis that present-day mantle heterogeneities could have been generated during the early crystallization of the primitive mantle.
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http://dx.doi.org/10.1038/s41467-022-35171-y | DOI Listing |
Sci Rep
January 2025
Saudi Geological Survey, P.O Box: 54141, Jeddah, 21514, Kingdom of Saudi Arabia.
Recent reconnaissance geochemical investigations have unveiled Cryogenian magmatism linked to the compressional accretionary phase, contributing to the growth of the Afif Terrane in the eastern Arabian Shield. The Cryogenian Suwaj intrusive suite, within the Afif Terrane, displays a compositional range from gabbro-diorite to tonalite-granodiorite. The uniform compositional variation is primarily due to magmatic differentiation within parental magma across multiple pulses.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
Department of Earth Sciences, University of Oregon, Eugene, OR 97403.
Volcanic provinces are among the most active but least well understood landscapes on Earth. Here, we show that the central Cascade arc, USA, exhibits systematic spatial covariation of topography and hydrology that are linked to aging volcanic bedrock, suggesting systematic controls on landscape evolution. At the Cascade crest, a locus of Quaternary volcanism, water circulates deeply through the upper [Formula: see text]1 km of crust but transitions to shallow and dominantly horizontal flow as rocks age away from the arc front.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
Archaeology & Palaeoecology, School of Natural and Built Environment, Queen's University, Belfast BT9 3AZ, United Kingdom.
Polar ice cores and historical records evidence a large-magnitude volcanic eruption in 1831 CE. This event was estimated to have injected ~13 Tg of sulfur (S) into the stratosphere which produced various atmospheric optical phenomena and led to Northern Hemisphere climate cooling of ~1 °C. The source of this volcanic event remains enigmatic, though one hypothesis has linked it to a modest phreatomagmatic eruption of Ferdinandea in the Strait of Sicily, which may have emitted additional S through magma-crust interactions with evaporite rocks.
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January 2025
School of Safety Engineering and Emergency Management, Shijiazhuang Tiedao University, Shijiazhuang, 050043, China.
In the eastern segment of the Central Asian Orogenic Belt (CAOB), there is widespread volcanic magma activity. However, there is still considerable controversy over the formation mechanisms and material sources of these volcanoes. The mantle transition zone (MTZ), as a necessary channel for the upward and downward movement of mantle material and energy exchange may provide crucial constraints on the dynamic mechanisms of volcanic activity.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
Department of Earth, Planetary, and Space Sciences, University of California, Los Angeles, CA 90095.
Crystallization of the lunar magma ocean yielded a chemically unique liquid residuum named KREEP. This component is expressed as a large patch on the near side of the Moon and a possible smaller patch in the northwest portion of the Moon's South Pole-Aitken basin on the far side. Thermal models estimate that the crystallization of the lunar magma ocean (LMO) could have spanned from 10 and 200 My, while studies of radioactive decay systems have yielded inconsistent ages for the completion of LMO crystallization covering over 160 My.
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