File:Station 6 boulders Figure 6-14.jpg

English: This is Figure 6-14 of the Apollo 17 Preliminary Science Report (NASA SP-330, 1973), which has the following caption:
Diagram of station 6 boulder showing relationships of large fragments and possible points of reassembly. Sample locations are designated on boulder fragments.
Text of the report related to station 6 is as follows:
Station 6 Boulder

Most of the samples collected at station 6 are from a large (6 by 10 by 18 m), fragmented boulder (fig. 6-14) lying at the end of a boulder track (fig. 6-15) that extends approximately one-third of the way (500 m) up the face of the massif. Two other boulder tracks appear to originate at approximately the same level (fig. 6-16). From this level to the top of the massif, boulder concentrations are common.

These boulder concentrations are probably derived from near-surface bedrock. At lower elevations, the bedrock in the massif is covered by a thick regolith and talus cover. At higher elevations, the massif is covered by a much thinner layer of fine material that allows the underlying bedrock to be easily excavated by the more abundant smaller cratering events. This is suggested by the change in slope from 25° in the upper two-thirds (upper 1000 m) of the massif to 21.5 ° in the lower one-third of the massif (~ 500 m above the base). One boulder track visible in figure 6-16 extends nearly 1000 m up the slope. At the lower end of this track is a large boulder that is darker than most of the other boulders on the lower one-third of the massif (fig. 6-17) and that is also darker than the station 6 boulders. A concentration of dark boulders occurs near its apparent source, and similar concentrations are scattered at approximately the same level elsewhere on the mountain face. Thus, a layer or lenses of darker rock may exist high on the mountain. Lighter boulders occur above and below. The lower light zone was sampled at the station 6 boulder.

The station 6 boulder broke into five pieces that are alined downslope. The largest is ~ 8 m across. The original boulder can be pieced back together, generally with only a small amount of rotation of any of the blocks. Several large fragments that may have broken from the boulder as it rolled downhill can be seen in and around the boulder track (fig. 6-18). Boulders 4 and 5 can be reassembled by minor rotation until similar appearing faces fit together (fig. 6-19). When this is done, vesicle foliation is in similar orientation in each boulder, and nonvesicular inclusions in both pieces also fit across the break. Boulders 1 and 2 also fit without substantial manipulation. It appears that boulder 1 can be raised and placed against boulder 2 (fig. 6-20). Boulders 2 and 3 are fitted together in much the same manner (fig. 6-21). The relationship of the structural split between boulders 1, 2, and 3 and boulders 4 and 5 is not as obvious, and the fit is still tentative. Figure 6-21 shows a nearly planar surface (A) on boulder 2, which dips approximately the same as the north face of boulder 4, as shown in figure 6-19. When boulder 4 is placed on this surface, the foliation, which appears to be planar concentrations of vesicles in boulder 2, is parallel with the foliation in boulders 4 and 5. Also, a series of widely spaced joints in boulder 4 is then alined with similar joints in boulder 2. A second, less-likely possibility is to place the north face of boulder 4 on planar surface (B) on boulder 2, adjacent to the one just described (fig. 6-13). However, structures seen in both boulders do not aline as well, and the shape of the fractured face of boulder 2 does not conform well with that of boulder 4.