There is little evidence about the crust of Mercury, except that it has a reflectance spectra similar to that of the Apollo 16 highlands and hence is unlikely to be granitic. Beneath this, the crust is believed to be brecciated and fractured by impacts to a depth of 20–25 km. The moon presents a special case of a primary crust composed essentially of anorthosite, which floated on an anhydrous magma ocean as a consequence of whole-moon melting at accretion. The significant feature about the Earth, in contrast to the other terrestrial planets, appears to be the presence of liquid water at the surface, coupled with plate tectonics and subduction, that enables recycling of subducted basaltic crust through the mantle. The northern crust of Mars appears to be basaltic, consistent with the geomorphic evidence for basaltic plains and volcanoes. This home was built in 2006 and last sold on for. As we just saw, the most densely cratered surfaces formed prior to 3.8 billion years ago, and the cratering rate has been roughly constant since that time. Note that the large circular craters in the lunar highland (Primary Crust) are filled with mare basalt (Secondary Crust). Because Apollo and Luna landing sites (all Nearside) were chosen for safety reasons or as geologically interesting but unrepresentative, their regional sampling of the Moon is biased. In terms of the lunar sample suite that is available for scientific study, the total mass of lunar meteorites is about 2.6 kg, compared with the total material returned by the Apollo and Luna missions of 382 kg and 300 g, respectively. Most are regolith, fragmentai, or melt breccias from the, .) Around 3.8 billion years ago they declined rapidly to roughly the present rate. In addition, ∼45 impacts produced basins, ranging in diameter from Bailly at 300 km, through the South Pole-Aitken Basin at 2600 km, to the putative Procellarum Basin at 3500 km, the existence of which is still debated. The geographical coordinates of the area are 27.4º North latitude and 0.8º East. There are bright and dark areas on the Moon’s surface. Very early on, cratering rates were high. If the plains units (intercrater and smooth) are lava flows, then they must have been very fluid with viscosities similar to fluid flood basalts on the Moon, Mars, Venus, and Earth. On Earth, in an area the size of the United States, a crater larger than 10 km across is expected to form every 10–20 million years and one larger than 100 km across, every billion years. (NASA Apollo 16 metric frame 3023.). Although the majority of crater ejecta is generally confined to within ∼2.5 diameters of the source crater, this still represents essentially hemispheric redistribution of materials in the case of an Orientale-sized impact on the Moon. We have learned that the maria are relatively young areas on the Moon which were generated after very large impacts penetrated the crust of our Moon and excavated basins. The words anorthosite, norite, and troctolite are used in various combinations as adjectives or nouns to describe coarse-grained rocks made up of various combinations of these three minerals. The highland feldspathic crust of the Moon, about 12% of lunar volume, formed in contrast within a few million years. The bulk of the near-surface rocks, which are impact products, are in the range of 3.8–4.0 Ga old. Most highland samples have ages in the range 3.8–4.3 billion years. This variant of Highland Park is exclusively for global travel retail and duty free markets and was first released in April 2010 having been distilled in 1973. Micro Full Moon: Nov 19. Most importantly, however, there exists an urgent need of many more grains. During a new moon (next one is October 27), gravitational pull brings up water in the soil, helping seeds that were recently planted. The bright-rayed craters on Mercury have a very low opaque mineral index that may indicate the craters have excavated into an anothositic crust. Nearly all zircons grew from granite magmas, not similar at all to those forming the oceanfloor or the lunar highlands. Except for the small amount of evidence for early mantle melting we are in the dark about how and when Earth's continents first formed (Figure 13). However, telescopic observations showed that the maria are very flat, and are very different from the so-called highlands. The conditions for the production of massive granitic crusts are probably unique to the Earth and require three or more stages of derivation from a primitive mantle composition. Robert G. Strom, in Encyclopedia of the Solar System (Second Edition), 2007. It may also be that a hotter Earth had a surface that was inherently unstable. Earth's earlier crust may therefore have been decimated by concomitant impacts. These zircons provide powerful evidence for the former existence of some unknown amount of continental crust in the Hadean. This contrast arises because of the Moon's cratering history. The Moon's path in Highland today. Micro New Moon: May 11. However, both planets show major differences and the Venusian surface appears to be mostly basalt, perhaps with a few scattered “pancakes” of more siliceous differentiates. Orbital measurements of gamma rays have shown that material rich in K, Th, and U is concentrated in the region of Mare Imbrium and Oceanus Procellarum. On Earth, in an area the size of the United States, a crater larger than 10 km across is expected to form every 10–20 million years and one larger than 100 km across, every billion years. The major minerals within the highland breccias are anorthite-rich plagioclase (CaAl2Si2O8), orthopyroxene ([Mg,Fe]SiO3), and olivine ([Mg,Fe]2SiO4); these occur both as mineral fragments and as plutonic rocks made up predominantly of these minerals. Pyroxene and spinel compositions, as well as exsolution features in pyroxenes, indicate that the meteorites were cooled only slightly more slowly than typical mare basalts, probably near the center of an uncommonly thick flow. This clustering has led to the concept of a “lunar cataclysm” or a spike in the collisional history at that time. Super Full Moon: May 26. The term magma includes not only the complex silicate melt, but the various crystallizing minerals, and may include bubbles of volatiles and globules of sulfide or metal melt. Indeed, when compared with lunar spectral reflectance data from the Clementine spacecraft, the distribution of FeO contents, KREEP-associated U and Th contents, and, indeed, the highlands nature of lunar meteorites themselves parallel the overall lunar character. It may also be that a hotter Earth had a surface that was inherently unstable. As this happened in comparatively recent times, the number of impact craters is far less than in the highland areas. Stuart Ross Taylor, in Encyclopedia of the Solar System (Second Edition), 2007. Little is known about the surface composition of Mercury. However, the highest albedo (0.36) on Mariner 10 images is not associated with a bright-rayed crater: It is a floor deposit in Tyagaraja Crater at 3° N latitude and 149° longitude. Remote sensing maps indicate that anorthosite is the dominant rock type of the highlands. The graph defaults to current time. 13). A recalibration and color ratioing of Mariner 10 images have been used to derive the FeO abundance, the opaque mineral content, and the soil maturity over the region viewed by Mariner 10. Either way, the data indicate that surface rocks affected by low-temperature fluids were probably being transported to significant depths and melted, as occurs today. At Highland, we do not mandate your giving to the church, however, we do believe that all believers should give in obedience to scripture – see below. Figure 15 shows a reconstruction of the lunar crater production rate with time. ), Encyclopedia of Physical Science and Technology (Third Edition), The lunar meteorites are the only group of meteorites for which the source body has been identified unequivocally. The basaltic lunar meteorites are derived from the mare regions. The feldspathic crust of the lunar highlands forms this type of example (Fig. Accordingly, surfaces that formed prior to 3.8 billion years ago are heavily cratered, and those that formed afterward are much less cratered. We have little evidence of what such a crust might have looked like. In addition to thermal subsidence, the basins may be loaded by later mare volcanism, leading to further subsidence and stress. Despite the complex history, a number of fragments of ANT rocks collected from the breccia have yielded isotopic ages greater than 4.4 billion years (Gy), indicative of crustal formation dating back almost to the origin of the solar system.

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