GEOLOGIC HISTORY OF SELECTED CLIMBING CRAGS IN NEW YORK AND NEW ENGLAND

James Eger and John G. Van Hoesen, Department of Environmental Studies, Green Mountain College, One College Circle Drive, Poultney, VT 05765, egerj@greenmtn.edu

Figure 14:Field shot of Waimea on upper cliffs of Rumney.

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Source: ESRI Maps and Data DVD

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Figure 10: Digital elevation model (Source: USGS), depicting characteristic topography of the Chapel Pond area. Orange line designates Chapel Pond Slab.

Figure 9: Line drawing of the Chapel Pond region showing the relationship between different climbing areas (from Mellor, 1995).

Figure 11: Photograph illustrating various climbs on Cannon Cliff (from Sykes, 2001).

Figure 12: Digital orthophoto quad (Source: USGS), depicting characteristic topography of the Cannon Cliff area. Orange line indicates base of cliff and start of many climbs.

Fig. 1: Late Devonian time. Rocks are folded and contorted. Erosion going on all the time.

Fig. 2: Late Devonian time. Concommittant with or just after folding, intrusion of the New Hampshire magma series (ed and gm).

Fig. 3: Mississipian time. Intrusion of the White Mountain magma series (d and cm) in the Pawtuckaway Mountains and volcanic activity in the Little Rattlesnake Hill area. Faulting preceded and followed intrustion of White Mountain magma series.

Fig. 4: Present. Region eroded to present topography.

ABSTRACT: New York and New England have a complex and varied geologic history, which has resulted in various world-class rock climbing areas. This study documents the geologic history and characteristics of specific climbing areas in New York, Vermont, and New Hampshire. The ultimate goal of this study is to make the processes that created these areas understandable and available to the general public, as well as guide services through a full-length book. Both bedrock and surficial geologic process are discussed with respect to what rock types dominate certain climbing areas, what evidence of geologic events are visible from these climbs, and what makes each area suitable for recreational climbing. The areas investigated in this study include the Chapel Pond area in the High Peaks of the Adirondacks, NY; the Shawangunks’ in the Catskill Mountains, NY; Deer Leap of Sherburne Pass, VT; Brandon Gap on Mt. Horrid, VT; Rumney of Rumney, NH; Pawtuckaway in Raymond, NH; and Cannon Cliff in Franconia Notch, NH. PROJECT RATIONALE: - Anecdotal evidence (discussions with guides and climbers) suggest a need to provide a geologic framework for many climbing areas

- This study is a precursor to a much broader investigation, with the ultimate goal to produce a book understandable by the layperson.

DISCUSSION: The geologic history of New England is complicated, diverse and awe inspiring. This geologic richness and diversity often takes form as outcroppings of rock suitable for roped climbing and bouldering. We have chosen these few select areas to illustrate the point that little information exists on many of these regions, much of the data that is available is outdated (e.g. - Pawtuckaway reference is pre-plate tectonics), and that no source of reference currently exists for people utilizing these areas who are interested in the geologic history. This is a preliminary attempt at surveying the geologic literature and distilling it into a “story” that will interest geologists and climbers alike. Our long-term goal is to produce a short interpretive guidebook that climbers, hikers, guides, etc., may find useful while exploring these diverse areas throughout northern New York and New England. Although this final product will also be far from a comprehensive compendium describing the geology in fine detail, it will provide readers with a broad understanding of the history of the rocks and region they are engaging.

Figure 1: Location map depicting the distribution of selected climbing areas in New York and New England.

BRANDON GAP, VERMONT: Brandon Gap is a highly complicated area both in terms of lithology and physical appearance. The Mount Horrid cliffs and the massive talus field below are part of the Precambrian Mount Holly complex, which contains varieties of schists, gneisses and quartzites. These are the basement rocks that form the core and axis of the massive Green Mountain anticlinorium. Outcrops of the same complex from the southern Green Mountains have put the ages between 900 million and 1.15 billion years old. This formation experienced regional dynamothermal metamorphosed (Goullaud 1969) during that time and was originally igneous intrusive. Now, it is “augen and banded Precambrian gneisses of almandine-amphibolite faces derived from a quartzo-feldspathic sequence” (Goullaud 1969). Common minerals associated with this area include many common silicates (quartz, biotite, muscovite, & feldspar) as well as many others including sericite, chlorite, epidote, Iron-rich minerals, and traces of magnetite. There are two distinct places to climb here: on the upper cliffs and spire, or on the boulders that pepper the base of the talus field. The cliffs and spire are fun but not worth detracting from the bouldering below. It appears that the boulders have slowly pealed off the upper cliffs and tumbled down to the less steep ground below. At some point in the process a massive block cut loose and came to rest in its present position as a 70-foot high, free-standing spire. It appears as if there have been no significant rockfalls in quite some time.

BUCK MOUNTAIN, NEW YORK: The lower cliff of Buck Mountain is composed of a metasedimentary formation on the outskirts of the Adirondack uplift. The cliff is composed of an unamed biotite-quartz-plagioclase gneiss with varying content of garnet, sillimanite, and biotite (Fisher et al. 1970). The unit varies in color from light tan to brown when weathered to white to off-white when freshly exposed and exhibits large crystals of garnet and trace amounts of biotite. A clear foliation is present and the outcrop tends to break along this foliation in a blocky manner. The exact age is unknown, but it is estimated to be Middle Proterozoic.

CANNON CLIFF, NEW HAMPSHIRE: Franconia Notch is home to Cannon Cliff, one of New England’s largest granite walls. Cannon is part of the Mt. Lafayette granite porphyry within the White Mountain (WM) magma series batholith. The WM magma series has been dated to the late Mississippian-early Pennsylvanian era. The granite is massive and alkaline with almost no foliations and mostly gray in color. Cannon Cliff is an exfoliating granite dome and has the distinct appearance of a peeling onion. Crystal sizes are generally medium to fine. There is a massive talus field at the base of this mile-long cliff that is still getting “donations” from above. Cold winters, warm summers, and relatively unstable exfoliated slabs all lead to frequent rock fall (as was the case with the Old Man of the Mountain). A prominent buttress extends from the southern end—home to the classic Whitney-Gilman Ridge—and separates the southern and northern faces. This buttresses formation has been the result of erosion of the 10-20 ft wide Black Dike. This mafic, diabase intrusion runs nearly vertical and has eroded at a rate much faster than the surrounding granite.

RUMNEY, NEW HAMPSHIRE: The Rumney climbing area is composed of metasedimentary rocks of the Littleton formation. Littering Rattlesnake Mountain are the two dozen or so dark schist cliffs. These mica, quartz-mica, garnet, and sillimanite schists were once muds during the early Devonian period before major regional metamorphism took place during the late Devonian (Fowler-Billings and Page, 1942) Micaceous quartzites are also present in the Littleton formation and can be seen on a few cliffs. Metamorphism produced a distinct foliation (easily seen on Jimmy Cliff and Wiamea Wall) as well as large scale folding; overturning original bedding planes so that they now stand on their side. On the far eastern side of Rattlesnake Mountain there are also outcrops of Concord Granite which is fine to coarsely crystalline and composed of potassium feldspars, oligoclase, quartz, biotite, and muscovite (Page, 1940).

PAWTUCKAWAY, NEW HAMPSHIRE: Pawtuckaway State Park is the home of one of the largest and densest boulder clusters in the world. Some of these massive monzonite erratics that have dimensions of over 50 feet and stand as tall as 40 feet high, were moved to their current location by glaciers during the last ice age. Boulders were plucked from the Devil’s Den area on North Mountain as the glaciers passed over the area (Freedman, 1950) Texturally, the boulders are coarsely crystalline and predominantly equigranular biotite, hornblende, and potassium feldspar. (Roy and Freedman, 1944) Pawtuckaway Mountain is coarsely-crystalline monzonite of the White Mountain magma series and was formed during the late Mississippian period, some 275 MA. The formation process began with a pluton of mafic granite-like rocks known as gabbro, diorite, and diabase. A circular fracture opened up around the mafic pluton and magma of differening composition filled the fracture. The resulting “circle” of monzonite is known as a ring-dike and is observable on the outer perimeter of Pawtuckaway Mountain (North and South Mountains) (Eby, 1984). During the same period, magma also intruded through the middle of the eroding pluton, resulting in a central mass of coarse-grained monzonite, which is now Middle Mountain (Freedman, 1950)

REFERENCES: Billings, Marland P. and Williams, Charles R., 1935, Geology of the Franconia Quadrangle New Hampshire. State Planning and Development Commision, Concord, New Hampshire, 35 p. Davidson, Bruce J., 1981, A structural study across Brandon Gap, Vermont. Middlebury College Thesis, 53 p. Doll, Charles G., 1961, Centennial Map of Vermont. Vermont Geological Survey, Waterbury, VT, 1:250,000. Eby, G. N., 1984, Mount Pawtuckaway ring-dike complex. In Hanson, L.S. (ed.) Geology of the Coastal Lowlands, Boston, MA to Kennebunk, ME. New England Intercollegiate Geologic Conference, Salem, Ma, pp. 240-248. Fisher, Donald W., Isachsen, Yngvar W., Rickard, Lawrence V., 1970, Geologic Map of New York: Hudson-Mohawk Sheet, New York Sate Museum Map and Chart Series No. 15, 1:250,000. Fowler-Billings, Katharine and Page, Lincolin R., 1942, The geology of the Rumney Quadrangle: New Hampshire. State Planning and Development Commission, Concord, NH, 31p. Freedman, Jacob, 1950, The Geology of the Mt Pawtuckaway Quadrangle: New Hampshire. New Hampshire State Planning and Development Commission, Concord, NH, 34p. Goullaud, Lee H., 1969, Petrologic studies at Brandon Gap, Vermont. Middlebury College Thesis, 66 p. Isachsen, Y.W., Landing, E., Lauber, J.M, Rickard, V, and Rogers, W.B., 2000, Geology of New York: A Simplifed Account.The New York State Education Department, Albany, NY, 294p. Jaffe, Harold W. and Jaffe, Elizabeth B., 1987, Geology of the Adirondack High Peaks Region: A Hikers Guide. Adirondack Mountain Club, Glens Falls, NY, 201p. Mellor, Don, 1995, Climbing in the Adirondacks: A Guide to Rock and Ice Routes in the Adirondack Park. Adirondack Mountain Club, Lake George, NY, 476p. Roy, John C. and Freedman, Jacob, 1944, Petrology of the Pawtuckaway Mountains, New Hampshire. Geological Society of America Bulletin, 55: 905-919. Sykes, Jon, 2001, Secrets of the Notch: A Guide to Rock & Ice Climbing on Cannon Cliff and the Crags of Franconia Notch. Huntington Graphics, Canada, 287p. Williams, Charles R. and Billings, Marland P., 1938, Petrology and structure of the Franconia Quadrangle, New Hampshire. Bulletin of the Geological Society of America, 49: 1011-1044.

DEER LEAP, VERMONT: Deer Leap is also located in the Tyson Formation of the Mount Holly Complex. The rocks exposed at this outcrop are very solid and finely-crystalline. There are numerous cracks that split the main face and are wonderful climbs. However, this is not the only kind of climbing available; this crag has some exceptionally fun and thin face climbs. The abundant bands of quartz offer great tiny holds thanks to differential weathering. Another fascinating feature is a set of small chevron folds near the top of the cliff (best seen when finishing Monkey Overhang).

CHAPEL POND, NEW YORK: The Chapel Pond area is predominantly metanorthosite (MA) and gabbroic metanorthosite (GMA), composed predominantly of plagioclase feldspar (andesine-labradorite) with trace minerals including hypersthene, augite, and ilmenite. Initially the anorthosite was created between 1000oC and 1300oC (twice the temperature at which granite melts), and at depths of up to 30 Km. Because of the slow cooling, the crystal sizes are very coarse to medium-grained. What differentiates the MA from the GMA is that GMA contains 10% or more mafic minerals and contains medium-sized crytals. The Beer Walls, Creature Wall, and Spider Wall are all within a small body of metanorthosite. This is surrounded largely by gabbroic metanorthosite, which houses Chapel Pond Slab, King Wall, and Washbowl Cliffs. There is a fault that runs parallel to route 73 on the western side and traverses directly under Chapel Pond and the base of the slabs here. Just to the west, the Chapel Pond canyon, which is home to the Beer Walls, also lies along this major fault system. One other notable feature here is the evidence of glaciation during the previous ice age. One can easily see the rounded mountain tops and smoothed bedrock in this area.

Figure 4: Digital elevation model (Source: USGS), depicting characteristic topography in the Brandon Gap/Mt Horrid area. Orange line designates boulder field at the base of Mt Horrid. Inset picture illustrates characteristic boulder in this region.

Figure 5: Digital elevation model (Source: USGS), depicting characteristic topography of the Pico Peak & Deer Leap area. Inset picture illustrates the dramatic exposure of Deer Leap.

Figure 2: Geologic map illustrating the location of Brandon Gap and Deer Leap in the Tyson Formation of the Mount Holly Complex (Doll, 1961)

(1) Chapel Pond, New York (2) Buck Mountain, New York (3) Brandon Gap, Vermont (4) Deer Leap, Vermont (5) Franconia, New Hampshire (6) Rumney, New Hampshire (7) Pawtuckaway, New Hampshire

LEGEND

The Great Cliff

Mt Horrid Cape Lookout Mountain

73

Pico Peak

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Deer Leap

Kent Pond

Black Mountain

Erebus Mountain Buck

Mountain

Lake George

Figure 8: Digital elevation model (Source: USGS), depicting characteristic topography of the Buck Mountain area. Orange line designates climbing areas.

Dix Mtn Nippletop

Gothics Lower Wolfjaw

Giant Mtn

73

Rattlesnake Mountain

Carr Mountain

Rumney

Baker River

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Figure 13: Digital orthophoto quad (Source: USGS), depicting characteristic topography of the Rumney area. Orange lines designate climbing areas.

North Mountain

Middle Mountain

South Mountain

Figure 16: Digital elevation model (Source: USGS), depicting characteristic topography of the Pawtuckaway area. Orange lines designate climbing areas. Inset picture is of a characteristic “Pawtuckaway” boulder.

Little Haystack Mtn

LafayetteMtn

Cannon Cliffs

Cannon MtnLonesome

Lake

Figure 15: Close-up of Geologic map of the Rumney Quadrangle (climbing area is highlighted by red rectangle). The western portion of the rectangle is dominated by the Littleton Formation and the eastern portion contains sparse outcrops of the Concord Granite (Page, 1940).

Figure 17: Schematic development of Pawtuckaway. Sc = Eliot formation, Sb = Berwick formation, Dl = Littleton formation, ed = Exeter diorite and qm = quartz monzonite, d = diorite, and cm = coarse monzontite (Freedman, 1950).

ACKNOWLEDGMENTS: We would like to thank Dr. Tim Grover at Castleton State College, Larry Becker with the Vermont Geological Survey and Dr. Jeffrey Munroe for their assistance and Green Mountain College for supporting undergraduate research through a undergraduate research assistantship (URA).

Figure 3: Close-up of folded quartz stringers in the Tyson Formation.

Figure 7: Close-up of garnet bearing biotite-quartz plagioclase gneiss of Buck Mountain.

Buck Mountain borders a normal fault that runs northeast along the eastern border of Lake George (Fisher et al. 1970). The mountain is an upthrown horst to the east of the Lake George graben. Portions of the Buck Mountain cliff appear to contain amphibolite with biotite, garnet and pyroxene. The climbing here is variable because many of the fractures form straight cracks, blocky faces exhibiting numerous weathered out garnet “pockets”.

Figure 6: Evidence for original sedimentary origin of Buck Mountain gneiss .