Modelling the ascent of picritic lunar magmas

2021 ◽  
Author(s):  
Marissa Lo ◽  
Giuseppe La Spina ◽  
Katherine Joy ◽  
Margherita Polacci ◽  
Mike Burton
Keyword(s):  
Thermal Evolution ◽  
Magma Ascent ◽  
Volatile Content ◽  
Major Element Composition ◽  
Analytical Instruments ◽  
Lunar Interior ◽  
Digital Elevation ◽  
Lunar Samples ◽  
Future Work ◽  
Compare And Contrast

<p>Quantifying the volatile content of the lunar interior is valuable for understanding the formation, thermal evolution, and magmatic evolution of the Earth and Moon. Petrological modelling and geochemical measurements have been used to study the volatile composition of the lunar interior. Improvements to analytical instruments have facilitated more precise measurements of the volatile content of lunar samples and meteorites, however, several problems remain with these measurements, hence, the volatile content of lunar magmas has yet to be constrained with certainty. We propose a volcanological approach for inferring the volatile contents of different lunar magmas.</p><p>            A terrestrial magma ascent model has been modified for lunar applications. Numerous parameters were adjusted for lunar conditions, including: magma major element composition, from low-Ti (green and yellow glasses) to high-Ti (orange, red, and black glasses); H<sub>2</sub>O content; CO content; gravity; and pressure. The model calculated values for gas exsolution, viscosity, mass flow rate, and several other ascent processes, from a depth of 10 km to the surface. Using these results, we will assess the effect of varying magmatic volatile content on lunar magma ascent processes. We will also compare and contrast our results with existing models for lunar magma ascent, as well as models for magma ascent on other planetary bodies. Future work will involve modelling eruptions, using results from the magma ascent model, and verifying the results of the models using images and digital elevation models of the lunar surface.</p>

Intershield geochemical differences among Hawaiian volcanoes: implications for source compositions, melting process and magma ascent paths

1993 ◽  
Vol 342 (1663) ◽  
pp. 121-136 ◽  
Keyword(s):  
Melting Process ◽  
Isotope Ratios ◽  
Magma Ascent ◽  
Small Radius ◽  
Element Abundance ◽  
Isotopic Ratios ◽  
Large Radius ◽  
Major Element Composition ◽  
Mauna Loa ◽  
Melt Segregation

As Hawaiian volcanoes develop, their lavas systematically change in composition and isotopic ratios of Sr, Nd and Pb. These trends provide important constraints for understanding plume-related volcanism as a volcano migrates away from the hotspot. There are also geochemical differences between Hawaiian shields. In particular, lavas from adjacent shields such as Kilauea and Mauna Loa on Hawaii and Koolau and Waianae on Oahu have significant differences in abundances of some major and incompatible elements and isotopic ratios of Sr, Nd and Pb. Some incompatible element abundance ratios, such as Zr/Nb and Sr/Nb, are correlated with intershield differences in Sr and Nd isotope ratios, but these isotopic ratios are not correlated with intershield differences in major element composition, or even parent/daughter abundance ratios such as Rb/Sr and Sm/Nd. Moreover, at Kilauea and Mauna Loa the intershield differences have apparently persisted for a relatively long time, perhaps 100 ka. These intershield geochemical differences provide important constraints on plume volcanism. Specifically, (i) each volcano must have distinct magma ascent paths from the region of melt segregation; (ii) the 25-50 km distance between adjacent, but geochemically distinct, shields requires that the sources vary on a similar scale, and that the melt production region is similarly restricted. The absence of correlations between lava compositions and radiogenic isotope ratios provides evidence for significant differences in melting process such as each shield forming by a different mean extent of melting with melt segregation at different mean pressures. Two types of models are consistent with the intershield geochemical differences: (i) a relatively large radius, ca . 40 km, plume conduit with a systematic spatial distribution of geochemical heterogeneities; or (ii) a small radius, less than 20 km, plume conduit composed of geochemically distinct diapirs. Because relatively small radius diapirs of limited vertical extent are too small to create the large Hawaiian shields, a possible alternative is a continuous conduit containing solitary waves which transport geochemically distinct packets of material.

scholarly journals The New Moon: Major Advances in Lunar Science Enabled by Compositional Remote Sensing from Recent Missions

Geosciences ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 498
Author(s):  
Deepak Dhingra
Keyword(s):  
Rapid Evolution ◽  
The Moon ◽  
New Paradigm ◽  
Lunar Science ◽  
Lunar Interior ◽  
New Findings ◽  
Lunar Samples ◽  
Resource Exploration ◽  
Globally Distributed

Volatile-bearing lunar surface and interior, giant magmatic-intrusion-laden near and far side, globally distributed layer of purest anorthosite (PAN) and discovery of Mg-Spinel anorthosite, a new rock type, represent just a sample of the brand new perspectives gained in lunar science in the last decade. An armada of missions sent by multiple nations and sophisticated analyses of the precious lunar samples have led to rapid evolution in the understanding of the Moon, leading to major new findings, including evidence for water in the lunar interior. Fundamental insights have been obtained about impact cratering, the crystallization of the lunar magma ocean and conditions during the origin of the Moon. The implications of this understanding go beyond the Moon and are therefore of key importance in solar system science. These new views of the Moon have challenged the previous understanding in multiple ways and are setting a new paradigm for lunar exploration in the coming decade both for science and resource exploration. Missions from India, China, Japan, South Korea, Russia and several private ventures promise continued exploration of the Moon in the coming years, which will further enrich the understanding of our closest neighbor. The Moon remains a key scientific destination, an active testbed for in-situ resource utilization (ISRU) activities, an outpost to study the universe and a future spaceport for supporting planetary missions.

scholarly journals Time-evolving surface and subsurface signatures of Quaternary volcanism in the Cascades arc

Geology ◽  
2020 ◽  
Vol 48 (11) ◽  
pp. 1088-1093
Author(s):  
Daniel O’Hara ◽  
Leif Karlstrom ◽  
David W. Ramsey
Keyword(s):  
Cascade Range ◽  
Magma Ascent ◽  
Upper Crust ◽  
Western North America ◽  
Quaternary Volcanism ◽  
Subsurface Structures ◽  
Digital Elevation ◽  
Crustal Structures ◽  
Spatial Focusing ◽  
Scale Surface

Abstract Increased resolution of data constraining topography and crustal structures provides new quantitative ways to assess province-scale surface-subsurface connections beneath volcanoes. We used a database of mapped vents to extract edifices with known epoch ages from digital elevation models (DEMs) in the Cascades arc (western North America), deriving volumes that likely represent ∼50% of total Quaternary eruptive output. Edifice volumes and spatial vent density correlate with diverse geophysical data that fingerprint magmatic influence in the upper crust. Variations in subsurface structures consistent with volcanism are common beneath Quaternary vents throughout the arc, but they are more strongly associated with younger vents. Geophysical magmatic signatures increase in the central and southern Cascade Range (Cascades), where eruptive output is largest and vents are closely spaced. Vents and correlated crustal structures, as well as temporal transitions in the degree of spatially localized versus distributed eruptions, define centers with lateral extents of ∼100 km throughout the arc, suggesting a time-evolving spatial focusing of magma ascent.

scholarly journals Isotopic evidence for volatile replenishment of the Moon during the Late Accretion

2019 ◽  
Vol 6 (6) ◽  
pp. 1247-1254 ◽  
Author(s):  
Yanhao Lin ◽  
Wim van Westrenen
Keyword(s):  
Dynamic Models ◽  
Temporal Evolution ◽  
Carbonaceous Chondrite ◽  
Isotopic Ratios ◽  
Delivery Time ◽  
The Moon ◽  
Lunar Interior ◽  
Delivery Times ◽  
Lunar Samples ◽  
Water Contents

AbstractThe traditional view of a dry, volatile-poor Moon has been challenged by the identification of water and other volatiles in lunar samples, but the volatile budget delivery time(s), source(s) and temporal evolution remain poorly constrained. Here we show that hydrogen and chlorine isotopic ratios in lunar apatite changed significantly during the Late Accretion (LA, 4.1–3.8 billion years ago). During this period, deuterium/hydrogen ratios in the Moon changed from initial carbonaceous-chondrite-like values to values consistent with an influx of ordinary-chondrite-like material and pre-LA elevated δ37Cl values drop towards lower chondrite-like values. Inferred pre-LA lunar interior water contents are significantly lower than pristine values suggesting degassing, followed by an increase during the LA. These trends are consistent with dynamic models of solar-system evolution, suggesting that the Moon's (and Earth's) initial volatiles were replenished ∼0.5 Ga after their formation, with their final budgets reflecting a mixture of sources and delivery times.

scholarly journals Understanding the origin and evolution of water in the Moon through lunar sample studies

2014 ◽  
Vol 372 (2024) ◽  
pp. 20130254 ◽  
Author(s):  
Mahesh Anand ◽  
Romain Tartèse ◽  
Jessica J. Barnes
Keyword(s):  
Lunar Soil ◽  
The Moon ◽  
Origin And Evolution ◽  
Water Abundance ◽  
Water Ice ◽  
Lunar Interior ◽  
Lunar Samples ◽  
Future Challenges ◽  
Unambiguous Detection ◽  
Ocean Ridge

A paradigm shift has recently occurred in our knowledge and understanding of water in the lunar interior. This has transpired principally through continued analysis of returned lunar samples using modern analytical instrumentation. While these recent studies have undoubtedly measured indigenous water in lunar samples they have also highlighted our current limitations and some future challenges that need to be overcome in order to fully understand the origin, distribution and evolution of water in the lunar interior. Another exciting recent development in the field of lunar science has been the unambiguous detection of water or water ice on the surface of the Moon through instruments flown on a number of orbiting spacecraft missions. Considered together, sample-based studies and those from orbit strongly suggest that the Moon is not an anhydrous planetary body, as previously believed. New observations and measurements support the possibility of a wet lunar interior and the presence of distinct reservoirs of water on the lunar surface. Furthermore, an approach combining measurements of water abundance in lunar samples and its hydrogen isotopic composition has proved to be of vital importance to fingerprint and elucidate processes and source(s) involved in giving rise to the lunar water inventory. A number of sources are likely to have contributed to the water inventory of the Moon ranging from primordial water to meteorite-derived water ice through to the water formed during the reaction of solar wind hydrogen with the lunar soil. Perhaps two of the most striking findings from these recent studies are the revelation that at least some portions of the lunar interior are as water-rich as some Mid-Ocean Ridge Basalt source regions on Earth and that the water in the Earth and the Moon probably share a common origin.

Tectonique et venues volcaniques en contexte de collision, exemple du massif néogène du Siroua (Atlas Marocain) : effets combinés d'une transformante et de la suture panafricaine

2001 ◽  
Vol 38 (3) ◽  
pp. 411-425
Author(s):  
J Chorowicz ◽  
A Emran ◽  
E M Alem
Keyword(s):  
Late Miocene ◽  
Active Faults ◽  
Suture Zone ◽  
Open Fractures ◽  
Magma Ascent ◽  
African Plate ◽  
Regional Deformation ◽  
Digital Elevation ◽  
Elevation Model ◽  
Convergence Trend

The Late Miocene – Early Pliocene Siroua strato-volcano is made of particular hyperalkaline rocks. It lies between the High-Atlas and the Anti-Atlas, in a collisional zone related to the continental subduction of the African plate under the Moroccan Meseta. Our field observations and analyses of SPOT, Landsat-MSS, and DEM (digital elevation model) imagery have permitted mapping of faults, joints, and volcanic edifices. The elongate shape of volcanoes and linear clusters of adjacent edifices, together with their relationships with faults, show that magma ascent was favored by tectonic crustal scale open fractures, essentially tension fractures, tail-cracks, and open faults. These fractures, together with other nonvolcanic, narrow, NNE-striking troughs, provide valuable information on the regional deformation since the Late Miocene. The shortening–extension type strain, which is responsible for the open fractures, is situated near the Azdem transform, a zone of active faults striking NNE, parallel to the convergence trend. The transform links two segments of the "Accident Sud-Atlasique," which constitute the border between the Moroccan Meseta and the African plate. The magma seems to originate from the lithospheric mantle, but asthenospheric material had previously migrated upward along the Panafrican suture zone. This mixed magma finally was transferred to the surface as a result of the onset of the open fractures prior to fault motions. The Siroua volcanic activity results from the conjunction of (1) a Panafrican suture zone and (2) a zone of open fractures due to "strike-slip" strain near a local transform inside the area of collision.

scholarly journals Modeling Lunar Pyroclasts to Probe the Volatile Content of the Lunar Interior

2021 ◽  
Vol 126 (4) ◽  
Author(s):  
Darien Florez ◽  
Christian Huber ◽  
Ralph E. Milliken ◽  
Julia Berkson
Keyword(s):  
Volatile Content ◽  
Lunar Interior

scholarly journals Modeling Lunar Pyroclasts to Probe the Volatile Content of the Lunar Interior

2020 ◽  
Author(s):  
Darien Florez ◽  
Christian Huber ◽  
Ralph E. Milliken ◽  
Julia Berkson
Keyword(s):  
Volatile Content ◽  
Lunar Interior

Present status of radio astrometry with baselines ≤ 35 km

1978 ◽  
Vol 48 ◽  
pp. 175-178 ◽  
Author(s):  
K. J. Johnston
Keyword(s):  
Present Status ◽  
Future Work

A summary of results for radio astrometry with baselines ≤ 35 km and priorities for future work are given.

Analysis of completed commercial semiconductors using EPMA

1996 ◽  
Vol 54 ◽  
pp. 502-503
Author(s):  
R. Packwood ◽  
M.W. Phaneuf ◽  
V. Weatherall ◽  
I. Bassignana
Keyword(s):  
Electron Probe Microanalysis ◽  
Electron Probe ◽  
Semiconductor Industry ◽  
Detection Limits ◽  
High Technology ◽  
Depth Resolution ◽  
Analytical Instruments ◽  
Wide Range ◽  
Numerous Element ◽  
Choice Method

The development of specialized analytical instruments such as the SIMS, XPS, ISS etc., all with truly incredible abilities in certain areas, has given rise to the notion that electron probe microanalysis (EPMA) is an old fashioned and rather inadequate technique, and one that is of little or no use in such high technology fields as the semiconductor industry. Whilst it is true that the microprobe does not possess parts-per-billion sensitivity (ppb) or monolayer depth resolution it is also true that many times these extremes of performance are not essential and that a few tens of parts-per-million (ppm) and a few tens of nanometers depth resolution is all that is required. In fact, the microprobe may well be the second choice method for a wide range of analytical problems and even the method of choice for a few.The literature is replete with remarks that suggest the writer is confusing an SEM-EDXS combination with an instrument such as the Cameca SX-50. Even where this confusion does not exist, the literature discusses microprobe detection limits that are seldom stated to be as low as 100 ppm, whereas there are numerous element combinations for which 10-20 ppm is routinely attainable.

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