Mount Moosilauke
Trails
7.2 miles - Mount Moosilauke and South Peak Loop. Start at The Moosilauke Ravine Lodge. Take Gorge Brook trail to the summit of Mt Moosilauke. Continue around to South Peak (0.2-mile detour off the trail for excellent views looking back up at Moosilauke and at the surrounding White Mountains). Finish by heading back down to the Ravine Lodge. See the following trail map from NH 4000 Footers for more information:
Geological History
Approximately 380 million years ago, the microcontinent Avalonia collided with Laurentia -- a craton, or slab of continental crust, that eventually became the geological core of North America. This collision formed mountains that rivaled the size of the Alps and Himalayas. The forces and pressures of these collisions transformed sedimentary rock into various forms of metamorphic rock. Following this mountain-building event, the mountains eroded until they became the White Mountains which we know and love today (1).
Mt. Moosilauke, one of the White Mountains, consists mostly of a metamorphic rock called the Littleton Formation (2). Fossils (brachiopods) found in the slightly metamorphosed member of this rock date back to the Devonian age (3), suggesting the rocks formed between 420 and 360 Million Years ago; this finding corresponds to the time of the continental collision which formed the White Mountains.
As with our other White Mountain hikes, we found evidence of glaciation from the Pleistocene Epoch 12,000 years ago. See the following sections, which details our findings, for more information.
Our Findings - May 24, 2021
An outcropping of quartz. This relatively hard mineral, a 7 on the Mohs scale, has survived the weathering that has removed rocks nearby. Hence, it stands out on the trail. (Toothbrush for scale.)
Wilder measuring the strike and dip of a rock outcropping near the top of Mt. Moosilauke's summit. He found the dip to be at an angle of 28 degrees, heading SSW.
Christian pointing out the very high prevalence of quartz, feldspar, and perhaps even biotite in this rock sample. This suggests that this specific rock cooled slowly. Also, note how the surrounding rocks lack these minerals.
Near Mount Moosilauke's summit, looking East. All the rocks suggest weathering both from the conditions atop, as well as the prevalance of homo sapiens.
From the summit, we got another opportunity to observe the occurence of u-shaped valleys left behind by glaciation.
Above: Looking East, towards the rest of the White Mountains. Mount Washington and Mt. Lafayette were both visible. Wilder is also standing on the right, observing the valleys below and contemplating the role that glaciation played 12,000 years ago.
Below: On our drive back, we observed a fascinating sample of metamorphic rock along I-93. The white patterns are a result of heat and pressure metamorphosing the previously igneous (granite) rock. Our sponsor, Ms. Latham, also provided us with the following insight: "The white patterns are likely felsic materials materials -- predominantly quartz, feldspar, and calcite. [The picture most likely depicts] medium-grade metamorphic rock, and the white bands could be folded/deformed quartz-rich pegmatites -- an igneous rock that cools very slowly, allowing for the formation of large crystals."
Wilder and I enjoying the view at Mount Moosilauke's summit! We highly recommend this hike -- the trails were not too hard to navigate and the views were incredible.