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84]
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AS17-0939 (M)
FIGURE 74 [above].- An oblique view looking northward along the east side of Mare Serenitatis. The Apollo 17 landing site (arrow) is near the lower edge. A nearly identical view was used earlier (fig.27), so the geology of the area will not be discussed again. We have included this picture here to serve as an index map for the next seven pictures, which are detailed views of parts of the Mare ridges visible in this photograph. -G.W.C.
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AS17-2313 (P)
FIGURE 75 [above].- This and the next six pictures are enlargements of specific areas to show the detailed form of the mare ridges seen at much smaller scale in figure 74. Here can be seen a small segment of the most prominent ridge enlarged about 45 times. When seen in detail, the ridge is spectacularly crisp and well formed. The main ridge here is shaped like a string of sausages. Smaller wormy ridges appear on either side. Cracks in the top of the ridge probably formed by buckling of the mare lavas. As the following figure show, most other parts of the ridge are less symmetrical than this part.- K.A.H.
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AS17-2313 (P)
FIGURE 76 [above].-This part of the ridge appears to have flowed over the ground to the right. A careful search will reveal several craters overridden by the ridge along its right edge. A large oblong crater on the ridge near the bottom of the photograph has evidently been distorted by the ridge; in fact, the right edge of the crater seems to be cut off. (See arrow.) One can imagine that a sheet of soft putty might form a similar ridge if it were thrust over to the right. Model experiments and observations of deformed rocks on Earth have shown that large masses of rocks, even hard rocks like basalt, can behave like putty over sufficiently long intervals of time.-K.A.H.
87
] FIGURE 77 [below].- Here again the ridge has overridden craters along its right side. Many other mare ridges that are older may once have looked like this. The freshest examples of lunar features, like this one, are the best places to look for hints on origin. - K.A.H.
ترجمة حرفية
[87] الرقم 77 [اقل].- هنا ريدج قد تجاوز الحفر على طول الجانب الايمن. فرس اخرى كثيرة الجدر القديمة التي ربما عندما يكون مشابها. أعذب لدي امثلة القمر الملامح ، ومثل هذا احدة ، هي افضل الاماكن للبحث عن تلميحات عن الأصل. - ك.ا.ه.
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AS17-2313 (P)
[88] FIGURE 78 [below].- At its north end of the ridge becomes a scarp that wraps around the base of the highlands like a shoved rug. Were the mare lavas thrust against the highlands? This might seem easiest to imagine if the lavas had been only partly solidified when they were deformed, but the lavas had had plenty of time to solidify. The ridge deforms numerous impact craters, such as the one near the bottom of the photograph. A long time-probably hundreds of millions of years- had to pass for these impact craters to form after the lavas crusted over and before the ridge formed.- K.A.H.
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AS15-9298 (P)
[89]
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AS17-2313 (P)
FIGURE 79 [above].-In the upper left corner of the photograph, a lunar ridge heads in a southeasterly direction toward the dark mantling unit that rings Mare Serenitatis. At its south end, one branch of the same ridge disappears in the dark mantling unit. The ridge boundaries are crisp and clear in the lighter mare materials in the left half of the photograph. However, in the much darker and topographically higher unit to the right, the ridge is subdued. (Owing to especially favorable lighting conditions, the true height of the east-facing scarp of the ridge is exaggerated.) The sequence of events worked out from the study of this area is as follows: (1) the Serenitatis basin was probably formed by the impact of a giant meteoroid; (2) the rim materials, and perhaps also the inner part of the basin, were flooded by dark basaltic lavas and associated volcanic (pyroclastic) debris; (3) the central part of the basin was filled by a lighter colored basaltic unit; and (4) gravitational adjustments to the enormous mass of volcanic fill probably caused the formation of the ridges in the light mare in the inner part of the basin and locally in the dark outer ring.-F.E.-B
جميع المعلومات والصور منسوخة من هذه الصفحة من موقع وكالة ناسا ومن الروابط الموجودة بنفس الصفحة
http://antwrp.gsfc.nasa.gov/apod/ap021029.html
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