The postulated moraine sits at the southwest corner of the confluence of outflow from a steep west to east discharging canyon and the main canyon, Kyle, which drains from north to south.

As I mentioned in the picture captions on the previous page, I knew one other person on the hike, an accomplished geomorphologist. She and I were skeptical. The moraine is a unique shape, yes, and it meets two requirements of moraines: unsorted and with striated rocks. But it takes a lot of imagination to make it into a terminal moraine from a glacier that stretched across the valley, originally, from west to east, as suggested in the article and on the tour. To accomplish this would require a huge glacier on the mountain, as suggested by the article and on the tour, with a major portion that came all the way down to this relatively low elevation in the main canyon. The elevation of the alleged moraine, as mentioned in the article, was about 8,300 feet, and there is one of the problems for me. Elsewhere, farther north in Nevada in Great Basin National Park where it is always cooler, they only came down to 9,000 feet, making me suspicious of this claim. But there is more to it than just elevation. NOTE: Subsequently I found that in Lamoille Canyon, in the Ruby Range near Elko, glaciers have come down to 7,300 feet elevation, so this objection may need to be scrapped. Lamoille Canyon is about 400 miles north of Las Vegas by car.

It will be interesting to see if the submitted Quaternary Geology article will receive a critical peer review. I have no doubt, now, after seeing the terrain and listening to the explanations, that there were alpine glaciers on the east-facing sides of the high ridge that extends south from Mount Charleston. I was skeptical about that too when I started on the tour, but now I am a believer. I think their arguments for that being so are strong, punctuated by there still being snow in places on those slopes in the middle of June even in this dry year. A gentleman who came up the trail later said he knew of three years in the 1990's when the snow never melted from those locations. During an Ice Age when the climate is both cooler and wetter, sure, I can believe there may be glaciers here!

But why did I not think the glaciers came all the way to the valley floor at about 8,300 feet, and why did I believe they likely terminated at just over 9,000 feet even during ice ages? Because that is the general Basin and Range evidence (based on field interpretation in Great Basin National Park, hundreds of miles to the north in Nevada) according to the USGS (http://www.aqd.nps.gov/grd/parks/grba/index.htm)

"Close beneath the summit of Wheeler Park, a bit of the Ice Age exists in the form of a small glacier, the only one of its kind in the Great Basin. A mere token, it calls to mind the powerful glaciers that capped the Snake Range only a few thousand years ago. Evidence of glacial activity is easy to find. Piles of glacial debris - boulders, sand, gravel - form mounds and ridges. Sparkling Teresa and Stella Lakes occupy hollows gouged by ice.

"These were alpine glaciers, not the huge continental ice sheets that enveloped the northern part of the continent. Here, ice never reached the valley floor. Instead, it melted at an elevation of about 9,000 feet. You can see this in the shape of the Baker Creek drainage. Above the melting point, glaciers plucked and carried bedrock, widening and smoothing the mountain slopes. Below the melting point, cascading streams cut sharp-sided canyons."

The description in the last paragraph above applies to the rough and steep cirque terrain above the Big Falls (at about 9,000 feet). And below those falls? Steep water-cut canyons with massive debris-outflows is my current opinion. The Lamoille Canyon information I have recently come across, however, makes these Great Basin National Park observations less compelling. But it doesn't completely allay my suspicion that the postulated elevation to which glaciers may have descended in the Spring Range is likely to be above 9,000 feet, and not into the main canyon at 8,300 feet. Lamoille Canyon glaciation was fed by a much larger upper canyon that is blocked on the east, south and west by tall peaks, making for late sunrises and early sunsets in summer as well as in winter. Snowfields persist through much of the summer even now.

So how to explain the striated rocks found in the valley floor?

Perhaps the glaciers carved up bedrock in higher reaches, in the cirque, and then plucked up pieces and deposited them in a higher terminal moraine in the cirque above the falls. As the alpine glaciers retreated, melt-water and fierce end-of-Ice-Age storms carried the till down the falls in debris-flow mode, depositing them in large heaps at the bottom of the narrow and steep canyon until it hit the gentler-slopes of the main canyon without significant consolidation and sorting.

The narrowness and steepness of the canyon is shown in the next photo, which is taken just as the rock wall of the canyon's south side ends and just before the main north-south canyon (Kyle) is entered (Mary Jane Falls is on the far wall):

Why does it matter? I don't think anything found here, no matter which way science sorts it out, will challenge current paleoclimte understanding in terms of timing and general precipitation amounts (doubling to tripling over the region during an Ice Age probably means even more of a multiplier at 11,000 + feet). But if the glaciers came as far down as 8,300 feet or so, at this moraine, there probably needs to be another look at the estimates of temperature-lowering (taking into account the protected nature of the location of the 'moraine' in a deep valley with high mountains to the west and to the east assuring late sunsets and sunrises).

Conventional wisdom has it that daytime temperatures may have been lowered less than 10 degrees on average. Southern Nevada was still warm and dry, but trees now restricted to above 6,000 feet came down somewhat below 4,000 feet. Lower yet in protected canyons with early sunsets where even now there are trees down to just under 4,000 feet, like in the red Rock area just west of Las Vegas. But the Las vegas Valley floor? A healthy desert, still.

But what bothered me some about the hypothesized origin of the 'moraine' aside from its needing to be the terminus of an ice sheet at a low elevation, is its shape when seen from other angles. In this next series of photos, it is obviously a continuation of an outflow-debris apron (all rather unsorted) that stretches east from the canyon's rocky mouth and then turns south as it meets the main canyon bottom.

Where I am standing to take this last photo is shown in the next photo:

Between this north and south wall of outflow debris is the deeply incised channel made by the current west to east canyon-bottom flow system. This suggests the north and south debris flow deposits were laid down in a rapid, almost catastrophic event, and then leisurely incised over the many thousands of years since that event. But the most interesting view from atop this wall of debris is to the southeast (the photo just above it was to the southwest):

This photo shows where the south wall of outflow debris terminates into the postulated moraine! Where it met the relatively level bottom of Kyle canyon it piled up and made a dam, as postulated, a dam that broke and left just a remnant behind.

This strongly suggests a continuous outwas of debris, not a glacial moraine, made the peculiar pile of interest. The following photos make this clearer. They are taken by walking on the south outflow debris pile into the direction of the so-called moraine:

The continuity of the formation is obvious, but it is also obvious that there is a difference in the sorting of the material over the top of the alleged moraine. Several vies at the top suggest the material in fact is only lighter in color, not sorted:

The striated rocks shown previously were located at the bottom, where the obvious foot trail is in this picture to the right. Given the rocks about to fall from along the entire height of the pile of debris, it is obvious that these straited rocks are not necessarily from the bottom of the pile, and could have been transported from much higher elevations upflow from the terminus of this debris pile.

The above photo shows the flow- (or colluvial, gravity-driven-) deposits on the lee side of the dam, while it was obstructing the Kyle Canyon flow channel. It shows some parallel structure, to me, and suggests to me a one-time flow prior to the dam-breach in the middle of the channel. Recall, however, as mentioned on the previous page, that the real geomorphologist on this tour believes it may be a colluvial deposit, material readjusted from the original deposit by gravity rather than by flowing water (but probably while it was still high in water content making it easier for it to slump in this manner). There may have been a throughflow, past this high part, on the west side of the canyon as well, given the low point on the south outwash formation before getting to the top of the alleged moraine in the photo below:

A final view of the postulated moraine: it looks like a very unique formation until you place it into its context, as has been done with the pictures shown above:

The next page will expand the setting of this feature up the canyon from whence its material came. The final page will cite descriptions of debris-outflows that will go a long way to explaining what is shown in these pages, I believe.