<\/a>Traverse to Station 9<\/strong><\/p>\n \u201cOkay, Bob. 240,\u201d Cernan confirmed the heading. This meant that Station 9 at Van Serg<\/em> Crater<\/em> lay a little south and west of Station 8 (see \u00a72, Fig. 12.160\u2191<\/span><\/a>).<\/p>\n \u201cBob, I think your rake sample here at the Sculptured Hills<\/em> is going to have to tell the tale [about this unit], combined with the observation that most of the blocks we saw were, like (the one) Gene sampled, [or] looked like subfloor gabbro. It\u2019s conceivable that the Sculptured Hills<\/em> could be the same kind of material. I think it\u2019s fairly clear that the boulder population does not resemble the [North<\/em> or South<\/em>] Massif<\/em> [boulder] population at all.\u201d Here, I was comparing the combination of the plagioclase-orthopyroxene boulder and the basalt fragments we sampled with the probable impact breccias of Stations 2, 6 and 7.<\/span><\/p>\n [As noted above in connection with samples 78235<\/strong>, 78236<\/strong> and 78238<\/strong> of the norite boulder, the probable real story of the Sculptured Hills<\/em> as remnants of an Mg-suite pluton ejected from Imbrium<\/em> would await the accumulated data and thinking stimulated by recent image and remote sensing missions around the Moon (Chapter 13).]<\/span><\/p>\n A few seconds later, I burst out with a laugh. Finally, Cernan had to experience being on the downhill side of the Rover as we headed back west across the regolith apron of the Sculptured Hills<\/em>.<\/p>\n \u201cYou been riding on this down-slope all the time!?!\u201d he exclaimed, to my continued laughter.<\/p>\n \u201cYes, but\u2026\u201d<\/p>\n \u201cAnd you hadn\u2019t said anything, huh?\u201d<\/p>\n \u201cScary, isn\u2019t it?\u201d I noted.<\/p>\n \u201cMan, I\u2019m glad I\u2019m driving!\u201d he said and joined in the laughter.<\/p>\n \u201cAnd Jack,\u201d Parker called, \u201cwhen you\u2019re not holding on with two hands, we\u2019d like the frame count from you.\u201d<\/p>\n \u201cWait a minute. Yeah. \u2026[Gene,] is that Van Serg<\/em> over there?\u201d<\/p>\n \u201cAhhhh\u2026\u201d<\/p>\n \u201c[Van Serg<\/em>] Should have a bearing of 234 and a range of 2.1,\u201d Parker noted, helpfully.<\/p>\n \u201cI think it\u2019s [over there],\u201d Cernan said, pointing toward the east rim of Cochise<\/em> as he headed southeast to get around SWP Crater<\/em>.<\/p>\n \u201cI don\u2019t know. \u2026No\u2026it\u2019s [to the left of that].\u201d<\/p>\n \u201cWe got to get around SWP<\/em> \u00a0here and then [maybe we can see it]. Well, that\u2019s [in the way], and then head on more westerly.\u201d<\/p>\n \u201cLMP frame is at 80.\u201d<\/p>\n \u201cSWP<\/em>\u2026or Bowen<\/em>, I mean. \u2026Bowen<\/em>, I guess that is.\u201d<\/p>\n \u201cWell\u2026that\u2019s SWP<\/em> over there,\u201d I noted, pointing to the right. \u201cBowen<\/em> is out here ahead of us.\u201d<\/p>\n \u201cYeah. \u2026Guess he (Parker) said\u2026225? What did you say, Bob? 225 what?<\/p>\n \u201cBowen<\/em> isn\u2019t much of a crater on the map,\u201d I observed, meaning it looks more formidable close-up than it had been mapped.<\/p>\n \u201c234 \/ 2.1,\u201d came up from Parker, but we were not reading him well through the Challenger<\/em> communications system.<\/p>\n \u201c234 \u2026,\u201d I repeated, hesitantly.<\/p>\n \u201cHeading ought to be about 240; 240 for a heading for there\u2026\u201d<\/p>\n \u201cDid you hear him?\u201d Cernan asked. \u201cI didn\u2019t hear him.\u201d<\/p>\n \u201c240 [heading]. Are you not reading him?\u201d I asked.<\/p>\n \u201cBut what did he say for bearing and range? That\u2019s what I\u2019m interested in.\u201d Cernan wanted to \u201cfly\u201d an arc to a point rather than try to follow a heading to that point.<\/p>\n \u201c2\u20263\u20264…2 point 1,\u201d Parker said again, slowly.<\/p>\n \u201c240. State bearing and range, Bob,\u201d I asked on top of his call.<\/p>\n \u201cOkay. I got that,\u201d Cernan said.<\/p>\n \u201cAnd we think you\u2019re even farther north than I was saying,\u201d Parker added, trying to clarify. \u201cMaybe it\u2019s about 215 would be your heading for there.\u201d<\/p>\n \u201cOkay, Bob. I\u2019ll find it. 234\/2.1.\u201d Trying to stay on a heading, with all these large craters between us and Van Serg<\/em>, would be more difficult than just working our way to a point defined by bearing and range from the SEP transmitter site.<\/p>\n \u201cAnd all the big blocks still look like subfloor from the Rover,\u201d I told Parker. \u201cBut \u2018big blocks\u2019 in here are only about a third of a meter in diameter. And they\u2019re sub-rounded to sub-angular. Okay. We\u2019re out on the plains again now, just off the break in slope [from the Sculptured Hills<\/em>].\u201d<\/span><\/p>\n <\/a><\/p>\n <\/a><\/p>\n <\/a><\/p>\n <\/a><\/p>\n [My traverse photos AS17-142-21746-51, in addition to having the South Massif<\/em> and Bear Mountain <\/em>as a backdrop, show a very mature regolith surface that is almost devoid of rocks larger than a few centimeters in average diameter. This would be a surface developed on the ejecta blanket around SWP<\/em> and Cochise Craters<\/em>.<\/span><\/p>\n From Cochise<\/em>, we could drive directly to Station 9 and Van Serg Crater<\/em> (AS17-142-21783-90), the latter being also situated on the ejecta blanket of Shakespeare<\/em>. Although we could visually identify the relatively dark rim of Van Serg<\/em>, the traverse photos primarily show the concentration of rock and breccia fragments around the crater.]<\/span><\/p>\n \u201cThat stuff sure looks like outcrop down in the East Massif<\/em> on the lower slopes,\u201d observed Cernan as he steered south around SWP<\/em>, \u201cwhere the high (low) albedo is. Doesn\u2019t it? See it over there?\u201d (This outcrop area is shown in AS17-146-22367, (Fig. 12.147\u2191<\/span><\/a>, \u00a72), just over the SEP antenna; and also in Fig. 12.182a\u2191<\/span><\/a>\u00a0above, just left of the central reseau cross.)<\/span><\/p>\n \u201c<\/strong>Yeah. Yeah; it does. \u2026It (the outcrop area) was one of my guidelines for the geophone deployment\u2026[I mean] guide points\u2026There\u2019s some more of that blue-gray rock there on the east end of the South Massif, down low.\u201d<\/span><\/p>\n \u201cYep.\u201d Cernan headed more to the southwest as we passed\u00a0SWP Crater<\/em>.<\/p>\n <\/a><\/p>\n <\/a><\/p>\n <\/a><\/p>\n [Because of the need to drive southeast around SWP Crater<\/em>, photographs AS17-142-21751-56 include the apparent large rock outcrops on a hill near the south end of the East Massif as well as the East Massif<\/em> itself. The smooth slopes of Bear Mountain<\/em> are visible in several of these images.]<\/span><\/p>\n \u201cIt (the east end of the South Massif<\/em>) looks like it might have been a slump block or something,\u201d I noted, looking to the southwest (AS17-142-21755).<\/span><\/p>\n <\/a><\/p>\n \u201cYep,\u201d agreed Cernan. \u201cYou can see it\u2019s blue-gray because of it\u2019s contrast with the light mantle.\u201d<\/span><\/p>\n \u201cYep. It might be a slump block,\u201d I said, reinforcing my earlier thought, \u201cor something like that.<\/span><\/p>\n \u201cJack, I\u2019m going to go to the left.\u201d<\/p>\n \u201cYou going to go through [Cochise<\/em>) Crater<\/em>]?\u201d I asked with a laugh.<\/p>\n \u201cNeed 234 (bearing)\u2026\u201d.<\/p>\n \u201c[Should we go east, more?]<\/p>\n \u201cNo, No. I\u2019m going over here. This is closer. It\u2019s a shorter cut.\u201d<\/p>\n \u201cThat\u2019s probably Bowen<\/em> there, don\u2019t you think?\u201d I suggested.<\/p>\n \u201cI think [so]\u2026\u201d<\/p>\n \u201cAhhh, well (not sure)\u2026\u201d<\/p>\n \u201cWell, see, we never got too far [east]\u2026\u201d<\/p>\n \u201cHow about a range and bearing, guys,\u201d requested Parker.<\/p>\n \u201c[We] aren\u2019t very far from SWP<\/em>,\u201d I added to the mix of possibilities.<\/p>\n \u201cMaybe we got too far east\u2026[Bob,] It\u2019s 228\/3.4,\u201d Cernan reported. And we\u2019re moving along at 10 to 12 clicks. That\u2019s all it\u2019ll hack.\u201d<\/p>\n \u201cHow about an amps reading? We haven\u2019t had one of those for a couple of [hours].\u201d Distractions caused us to ignore this request from Parker.<\/p>\n \u201cStarting to rain again,\u201d I said, as one of the clamps on the replacement fender loosened and regolith particles began to fall on us\u2026 \u201cGot a crater ahead of you,\u201d I warned, suddenly.<\/span><\/p>\n \u201cOooh, boy,\u201d Cernan said as we bounced through a depression without slowing down.<\/p>\n \u201cDown-Sun [driving] isn\u2019t much easier than up-Sun,\u201d I commented.<\/p>\n \u201cIt\u2019s just easier on the eyes,\u201d he replied with a chuckle. \u201cYou [still] just can\u2019t see any more, that\u2019s all. \u2026You don\u2019t have that static [in the comm.], huh?\u201d<\/p>\n \u201cNope. \u2026Hope you\u2019ve still got an [OPS] antenna; I haven\u2019t looked recently.\u201d I should have noticed, however, when I helped him get off his back when he became wedged against the wheel at Station 8.<\/p>\n \u201cWell, there\u2019s no holes in the high-gain.\u201d A hole in the big antenna might indicate that Cernan had poked his antenna through the antenna net and broken it off.\u201d<\/p>\n \u201c[You] Might have hit it on a rock [when you fell].\u201d<\/p>\n \u201cOh, boy!\u201d Cernan bounced through another small crater.<\/p>\n \u201cWe\u2019re back into the [dark] mantle area [and the] population of fragments is still one percent or so. The crater out off to our left, which is at 227 and three point\u2026\u201d I tried to read the range readout from a bad angle. \u201cWhat is that? Three point what? Three?<\/span><\/p>\n \u201c3.3; 227\/3.3,\u201d confirmed Cernan.<\/span><\/p>\n \u201cIt is a fairly good-sized depression, but it\u2019s completely mantled. There\u2019s no blocks showing in the wall at all.<\/span> \u2026How do you read, Bob?\u201d With the static Cernan hears and the undulating terrain that might block our line-of-sight to Challenger<\/em>, I wanted to be sure that we were being heard. These transmissions constituted my only field notes for the mission. It is a fine line between too many interruptions from Parker and being sure that the communications are going through.<\/p>\n \u201cLoud and clear. We\u2019re listening.\u201d<\/p>\n \u201cNow, there\u2019s a crater in the wall of that depression or the small one near it. And it has one big block in the side, as if it penetrated the mantle and exposed some of the wall of the depression. Just about a 30-meter crater.\u201d<\/span><\/p>\n \u201cValley of Taurus-Littrow<\/em> is not planar!\u201d asserted the driver.<\/p>\n \u201cNo, it isn\u2019t,\u201d I agreed. \u201cI\u2019m glad we changed it to a \u2018subfloor\u2019 instead of the \u2018plains\u2019 unit.\u201d This brought a laugh from Cernan, knowing that geologists worry a lot about terminology. We emphasize terminology for the same reasons pilots do, that is, to make as sure as possible that communications between professionals are clear. In fact, the use of the term \u201cplains materials\u201d to designate the valley floor map unit remained in use well into the mission year of 1972.<\/p>\n [Pre-mission photo-geological interpretation that the valley floor might be mantled by young, dark volcanic ash (pyroclastics) led to the more objective, albeit somewhat tortured use of \u201csubfloor\u201d rather than \u201cplains material\u201d for the rocks known to lie below this \u201cdark mantle\u201d. Even the low-resolution photographs available at the time showed that the subfloor unit is coherent enough to form visible blocks in and around some impact craters. Prevailing hypotheses about the nature of the subfloor unit consisted of (1) basalt, (2) the down-faulted top of the rim of the Serenitatis<\/em> basin, and (3) blocky debris thrown in from the bounding Massifs. The down-faulted rim of Serenitatis<\/em> of option (2) clearly existed at some depth, but the question was had it been covered subsequently by basaltic lavas or massif debris. The answer turned out to be both, i.e., massif debris followed by basaltic lava followed by massif debris (Chapter 13).<\/span><\/p>\n Early in EVA-1 it became clear that the subfloor rocks, at least to a depth of ~120 m or so (the original depth of Camelot Crater<\/em>), consisted of basalt, but its total thickness remained unknown until later analysis of the active seismic and gravity data established the basalt to be up to 1200 m thick in the vicinity of Challenger<\/em> (see discussion after Van Serg Crater<\/em>, below). Later, it became clear that the surface beneath the subfloor basalt was extremely irregular, probably similar to the knobby topography characteristic of the Sculptured Hills<\/em>. The nature of the apparent dark mantle stayed in doubt until post-mission microscopic examination of the orange and black \u201csoil\u201d samples from Station 4 identified them as consisting of volcanic ash.]<\/span><\/p>\n \u201c<\/strong>We\u2019re in the inner wall of the depression here,\u201d I reported and the rocks still look like subfloor gabbro. Boy, there\u2019s certainly not much variety. \u2026In general, there are few exotics\u2026\u201d Before I could elaborate, Cernan interrupted.<\/span><\/p>\n \u201cOoh, now that\u2019s got to be Cochise<\/em>.<\/p>\n \u201cAh, look at Cochise<\/em>,\u201d I agreed, impressed by the size and depth of this crater.<\/p>\n \u201cThat\u2019s Cochise<\/em>!\u201d<\/p>\n \u201cRoger. We think you\u2019re coming up on Cochise<\/em>.\u201d Parker added.<\/p>\n \u201cGet yourself a couple pictures while you\u2019re looking right at it.\u201d<\/p>\n \u201cCould you swing right. Swing right.\u201d I wanted to get a partial panorama of the crater interior.<\/p>\n [Once around SWP<\/em>, we drove more or less south (AS17-142-21757-64, generally toward the South Massif<\/em>, until we passed the north and east rims of Cochise<\/em> (AS17-142-21765-68, AS17-146-22404-08), still traveling over a very mature regolith surface. As we approached Cochise<\/em>, the frequency of larger blocks increased; however, there were no concentrations of blocks at the rim as are present at Camelot Crater<\/em> (EVA-2, Station 5), indicating that Cochise<\/em> is significantly older than Camelot<\/em>. Although fewer in number, like Horatio<\/em> and Henry Craters<\/em>, there are patchy concentrations of boulders on the inner walls of Cochise<\/em>. Before going to the south rim of Cochise<\/em>, we steered roughly east and south with good views of the East Massif<\/em>, Bear Mountain<\/em>, and the South Massif <\/em>(AS17-142-21769-77).]<\/span><\/p>\n \u201cBob, we are on the northeastern rim of Cochise<\/em>. I\u2019m going to work my way around the other side.\u201d<\/p>\n <\/a><\/p>\n <\/a><\/p>\n \u201cAnd Bob,\u201d I said, \u201clooking at the western (southwestern) wall of Cochise<\/em>, I can see a contact within the subfloor between albedo units, one of which is a light tan-gray and the other is a light blue-gray (AS17-142-21767 and 146-22408). [This contact] may reflect the two kinds of subfloor gabbro we\u2019ve already sampled \u2013 vesicular and non-vesicular. And that contact looked like it was (is) dipping\u2026apparent dip in the wall was (is) to the north\u2026in the west wall dipping to the north about 20 degrees.\u201d<\/span><\/p>\n![\"\"](\"http:\/\/www.colinmackellar.com\/blog\/wp-content\/uploads\/2021\/03\/Fig.-12.181a_Bowen_Location.jpg\")
Fig. 12.181a.<\/strong> Because there has been some confusion over the location of Bowen Crater<\/em> in various later maps, including editorial statements in the ALSJ<\/em>, possibly because we showed some confusion between SWP<\/em> and Bowen<\/em> craters coming down from Station 8, this figure illustrates where the crater I named for the noted petrologist Norman Bowen is actually located. As I noted a few lines above, \u201cBowen<\/em> isn\u2019t much of a crater on the map\u201d. \u00a0Although it is ~200 m in diameter, it has roughly only a very shallow 10 m depth; and it is difficult to see from ground level. It was correctly marked on our cuff checklist map between SWP<\/em> and Smith<\/em> craters (Fig. 12.181b). However, the notation \u201cBowen-Apollo\u201d<\/em>\u00a0underneath “SWP<\/em>” in the LROC Featured Sites traverse map above was not named or used by me. For a larger view in a separate window, click here<\/em><\/span><\/a>. (Base map from Apollo 17 LROC Featured Sites traverse).<\/span><\/p>\n![\"\"](\"http:\/\/www.colinmackellar.com\/blog\/wp-content\/uploads\/2021\/03\/Fig.-12.181b_eva3_lmpcdr20.jpg\")
Fig. 12.181b.\u00a0<\/strong>The sketch map on our cuff checklist. We, of course, did not go to Smith<\/em>; but rather from Station 8 at the lower right of SWP<\/em> (marked by red ‘x’), weaving in and out around small craters passing SWP<\/em> towards and around Cochise<\/em>\u00a0to Station 9 at Van Serg<\/em>, the small oval right of Gatsby<\/em>. North is to the right.\u00a0(LMP\/CDR-20, in the ALSJ<\/em><\/a><\/span>).<\/span><\/p>\n![\"\"](\"http:\/\/www.colinmackellar.com\/blog\/wp-content\/uploads\/2021\/03\/Fig.-12.181c_AS17-142-21750.jpg\")
Fig. 12.182a.<\/strong> Coming down off the slope from the Sculptured Hills<\/em>, there are only a few moderately-sized boulders such as the two angular ones seen here. The East Massif<\/em> (left<\/em>) and Bear Mountain<\/em> (right<\/em>) are in the background. (NASA photo AS17-142-21750).<\/span><\/p>\n![\"\"](\"http:\/\/www.colinmackellar.com\/blog\/wp-content\/uploads\/2021\/03\/Fig.-12.182_AS17-142-21754.jpg\")
Fig. 12.182b.<\/strong> Further down, the regolith surface lacks these larger boulders until we get closer to the ejecta blankets of Cochise<\/em> and Van Serg<\/em>, in particular. (NASA photo AS17-142-21754).<\/span><\/p>\n![\"\"](\"http:\/\/www.colinmackellar.com\/blog\/wp-content\/uploads\/2021\/03\/Fig.-12.183_AS17-142-21752.jpg\")
Fig. 12.183.<\/strong> In this turn to avoid craters, the outcrops along the East Massif<\/em> have been brought into stark focus as has some of the layering at the left and middle parts of the massif. Later LROC photos show these outcrops to be collections of very large boulders like the examples given in the next two figures. (NASA photo AS17-142-21752).<\/span><\/p>\n![\"\"](\"http:\/\/www.colinmackellar.com\/blog\/wp-content\/uploads\/2021\/03\/Fig.-12.184_Outcrop_01.jpg\")
Fig. 12.184.<\/strong> A vertical view of the top of the East Massif<\/em> foothill seen in the previous figure, right of middle, on a line directly above the TV camera. The largest boulder in the image measures ~56 m across the diagonal, upper left to lower right. This LROC photo resolution is 1.23 m\/px, and the reader can access it at: https:\/\/bit.ly\/3oFBNPM<\/a><\/span><\/em>. (NASA LROC QuickMap photo).<\/span><\/p>\n![\"\"](\"http:\/\/www.colinmackellar.com\/blog\/wp-content\/uploads\/2021\/03\/Fig.-12.185_Outcrop_02.jpg\")
Fig. 12.185. <\/strong>Another view of the boulders in the outcrop at the top of the East Massif<\/em> above the second foothill to the left in Fig. 12.183. The largest boulder here is only ~25 m across. The LROC photo resolution is 1.3 m\/px and the reader can access it at https:\/\/bit.ly\/2LqKtLr<\/a><\/span><\/em>. (NASA LROC QuickMap photo).<\/span><\/p>\n![\"\"](\"http:\/\/www.colinmackellar.com\/blog\/wp-content\/uploads\/2021\/03\/Fig.-12.186_AS17-142-21755_arw.jpg\")
Fig. 12.186.<\/strong> The east end of the South Massif<\/em> with Bear Mountain<\/em> to the left (above left of the TV camera). Note the bright line on the east slope near the horizon of the South Massif<\/em> as it intersects the darker west slope of Bear Mountain<\/em> marked by the black arrow. This may be the southernmost end of a possible slump block off the eastern slope. On the other hand, this hill may be a feature similar to Bear Mountain<\/em>. The area can be inspected by enlarging the unmarked view available here<\/em><\/span><\/a>.\u00a0(NASA photo AS17-142-21755).<\/span><\/p>\n![\"\"](\"http:\/\/www.colinmackellar.com\/blog\/wp-content\/uploads\/2021\/03\/Fig.-12.187_142-21767-678_pan.jpg\")
Fig. 12.187.<\/strong> Two of my traverse photos taken on the northeastern rim of Cochise<\/em> and combined to show the extent of the crater. Because of the motion between frames, parts of the LRV cannot be combined by the computer software. However, decreasing the brightness and increasing the contrast brings out the changes in albedo on the western wall of the crater. A larger view in a separate window is available here<\/em><\/span><\/a>.\u00a0(Combination of NASA photos AS17-142-21767, -768).<\/span><\/p>\n![\"\"](\"http:\/\/www.colinmackellar.com\/blog\/wp-content\/uploads\/2021\/03\/Fig.-12.188_146-22407-408_pan.jpg\")
Fig. 12.188.<\/strong> Two of Cernan\u2019s traverse photos taken at almost the same positions as mine in the previous figure. The larger scale version is available here<\/em><\/span><\/a>.\u00a0(Combination of NASA photos AS17-146-22407, -408).<\/span><\/p>\n