Geomorphology Field Trip

Geology 3265

Geomorphology Field Trip

We leave the Flagpole area, between Science and Hennings buildings, at 9am sharp. Take Morris Ave. North through Union, exit right onto 124 and follow the signs to 78 west. Along 78 note the jointed basalts of the Second Watchung, called the Preakness Basalt, and early Jurassic flood basalt in the Tr\J rift that eventually opened the Atlantic. The Watchungs limited the southward progression of Pleistocene glaciers.

Take Exit 36 (Basking Ridge/Warrenville) and reset the odometer 0.0. Turn right (North) onto King George Road. Drive to the crest of the hill (1.0 miles) and keep left at the church (right) and nursery (left). Turn right at Haas Road (1.7 mi.) then left onto Pond Hill Road (2.5 mi.). Pond Hill Road becomes School House Road. At the crest of the hill note the maximum elevation of the Long Hill Basalt, the Third Watchung. This basalt dips gently to the north and was the southern limit of Proglacial Lake Passaic after the Wisconsinan Glacier began retreating about 17000 years ago. Continue to the tracks (3.0 miles). If possible, both vans should park on the far side of the tracks. CAUTION: VERY ACTIVE RAILWAY.

Stop 1. Millington Gorge. After the meltwater flow of the Passaic River near Chatham was blocked by drift (the Madison Moraine), proglacial Lake Passaic rose and overtopped the Third Watchung here, forming a spillway waterfall, and eventually removing Basalt and shale to the level you see now.

Look at the streambed. Are there any really larger rocks (lag deposits)? Did the Passaic have enough competence to remove plucked boulders here? We say the Passaic is a (choose: fit / unfit) stream.

Can you find any other evidence of the glacier here?

Continue north down to Long Hill Road, and turn left. Continue to White Bridge Road, then turn right. CAUTION: PORTIONS MUDDY AND SLIPPERY. Continue to Pleasant Plains Road, turn left. Go through gate and continue to overlook parking lot with telescopes.

Stop 2. Great Swamp, a remnant of proglacial Lake Passaic. Ahead is the deepest portion of Great Swamp. It was bounded in the east by the Madison Moraine, on the South by the Third Watchung, and in the West by the Basking Ridge Moraine. A series of terraces (you are standing on one) attest to changing water levels. Increasingly lower spillways were exposed as the ice retreated north.

Return to the exit. Turn right onto White Bridge road, pass over the Passaic River where it exits the swamp, and return to the stop sign. Turn right onto S. Maple, and go another 0.3 miles, then make a left up the Basking Ridge Moraine on Colyer Road, noting the boulders on the hill slope. This is an Illinoian Stage moraine, formed when the Illinoian glacier retreated about 150,000 years ago. The boulders are different rock types than those found in local Wisconsinan Moraines. What does this suggest? ______.

At the top of the hill turn right, continue through town keeping left of the church, and continue to Route 202 in Bernardsville. Continue along 202 (portions Bernardsville Moraine) to the light at The Old Mill Inn and turn right, then exit onto Route 287 North. Get your camera ready.

As you pass exit 43 look right. A modern meander scar is cut into the Pleistocene drift. Is it (choose one: till / ICSD / other ______)?

On 287 take exit 44, Boonton Main Street, drive up the hill along 511 North, to Boonton Ave., turn right on 511 North. Zero the odometer. Continue 3.1 miles, and then turn left into Pyramid Mountain Natural Historical Area.

Stop 3. Pyramid Mountain Natural Historical Area. Roche Moutonée and Glacial Erratics. Here the glacier has abraded and plucked layers of gneisses, some of them migmatitic. Smaller rounded erratics from the Green Pond Conglomerate are also here. Return to the trucks.

Re-zero the odometer. Take a left out of the parking lot and continue on 511 North. After 4.2 miles at the light turn left onto 23 North.

Re-zero the odometer On the way we will pass a resistant ridge. It is at about 4.6 miles. It is formed into a (choose: hogback / cuesta) You may need to find and consult an online topo map after the trip. At about 9.2 miles take the exit for Reservoir Road. Cross Rt. 23 at the light. Immediately on your left is a small moraine, and on you right is a glacially deepened trough. Continue south down Reservoir Road, noting on your left where the road rises steeply to a crest. The forest changes to Spruce trees over a large drumlin, a streamlined hill of drift the shape of the bowl of a spoon. The drumlin is so large and forested that it is difficult to see. Past the crest the drumlin's downglacier slope lowers gently. Near the end of the road, turn around and return to Rt. 23. Re-zero the odometer.

Turn left onto 23 North. Proceed 7.8 miles through Franklin and up the hill on 23.

Food Stop. Turn right into the Wendy's for lunch. A QuickChek is next door if you did not bring water or want a custom made sub.

Re-zero the odometer. Turn right onto 23 North to Hamburg.

(Optional, if traffic permits a safe left turn) At 2.6 miles, just past the railroad overpass, make an immediate left onto Gingerbread Castle Road. After an additional 0.2 miles turn left into Bally Owen Bluff, a housing development. Proceed around the loop to the far side of the large rock outcrops in the center.

Stay in the truck. This is a Roche Moutonée. The glacier passed over than outcrop of the Allentown Dolomite here. It abraded the upglacier side and plucked the downglacier side, after the stoss and lee erosion we have been discussing.

Return to 23 North. Re-zero the odometer.

BE VERY CAREFUL TURNING LEFT.

After about 1.4 miles in Wantage look left. Sinuous Eskers erratics are in the fields. These formed as meltwater transported drift filled subglacial tunnels. A gravel company is excavating, sorting, and shipping sediment from this site. Watch for glacial erratics. Continue through the town of Sussex.

At 13.6 miles turn right into High Point State Park. Proceed to the monument parking lot.

Stop 4. High Point Monument. Just above the parking lot is another polished and plucked Roche Moutonnée. This ridge former is the middle Silurian Shawangunk Formation, usually a tough quartzite. It forms the crests of the Blue Ridge, here called Kittatiny Mountain.

Which way is the Shawangunk Formation dipping here? ______

Large gouges are visible on the flanks. The downglacier side is plucked. What are the linear features on the top? ______

This area is about 1400 feet above the bottom of the nearby Delaware River.

What is the minimum thickness of the glacier here? ______

Proceed to the monument, and face the parking lot. This view toward the northeast shows the Shawangunk ridge continuing into New York State. In the far distance, on a clear day, you can see the Catskills.

Walk around clockwise to the southeast view. The bedrock of the Kittatiny Valley is the middle Ordovician Martinsburg Shale, which unconformably lies under the Shawangunk. The angular unconformity was caused by the Taconic Orogeny, which raised mountains that were the source for the Shawangunk and Bloomsburg Formations. Across the Kittatiny Valley are the New Jersey Highlands: Proterozoic remnants of the Grenvillian collision that added the last piece to Rodinia, the Precambrian supercontinent. We saw these at Pyramid Mountain. The rocks are metamorphosed sediments, granites and amphibolites. The latter two are the roots of a volcanic arc accreted onto the future North America.

Continue around clockwise to the southwest view. The Shawangunk Ridge also continues in this direction. The Shawangunk is overlain by red sandstones of the Bloomsburg Formation. Since it is less resistant, the Bloomsburg Formation forms river valleys. Several of the hills close to the Delaware River Valley are drumlins; we shall pass them later along Clove Road.

In the far distance is Culver's Gap, an old water gap that is now dry.

Continue clockwise around the monument to the final view, facing northwest. Ahead you see the Delaware Valley flowing southeast toward Port Jervis, New York. There it makes a right angle turn and flows southwest toward Philadelphia and Delaware Bay.

Exit via Monument Drive. At the level of the lake turn right, and continue to the parking lot for the Dryden Kuser Natural Area. Walk as a group along the paved road. To the right large pieces of Shawangunk quartzite are sliding into the valley. Ahead the topography drops to a lower level. A Cedar Swamp occupies to low spot.

Stop 5. Drainage from this former lake, now a Cedar Swamp, was prevented by drift. The Holocene pollen from the varved sediments have been studied by Niering (1953). Below is a figure, made by Witte and Monteverde (2005) from Niering's results. Ten thousand years ago, this area was a Boreal Forest dominated by Spruce. It is now a Pine-Oak forest with White Cedars, Hemlocks, and Fiddlehead Ferns in wet areas. Dammed by moraine, further ice retreat uncovered lower outlet, did not completely drain, now filled with plant detritus

From Witte et al. (2005)

Return to Monument Drive. Turn right and drive up the hill to the Interpretive Center.

Stop 6. Monument Trail and Interpretive Center.

Walk a short distance along Monument Trail. What is the bedrock? ______What is the large subrounded boulder? ______

Walk behind the Interpretive Center and look at the perched lake below. Why hasn't this lake drained?

Drive back down to Monument Drive. Turn right, and then continue past Lake Marcia to the parking lot just beyond.

Stop 7. South Shore of Lake Marcia.

The rock rubble here consists of boulder sized Shawangunk quartzite. The boulders were broken out of the ridge above by frost wedging. Are the boulders rounded or angular? Such a boulder field is called ______.

The Martinsburg Formation is just below the level of the shore, and the glacier easily eroded the soft shale, deepening Lake Marcia. Differences in erodability are called “relative erodability”.

Drive to the exit and reset the odometer. Turn right.

Go about 0.5 miles down the mountain, then turn left at the sign for Sawmill Road. Go 0.1 miles and then turn right onto Park Ridge Road. Go another 2 miles to the park bench facing an Alpine Meadow on the left.

Stop 8. Spillway Lag Deposit, Recessional Moraine.

Ahead on the left is a low meadow, and a small brook (Parker Brook) crosses the road. To the right is another, lower Meadow. The small brook lies in a large cut through the Augusta Moraine. Large boulders cover the cut; they are much larger than the brook can move with the small difference in elevation available now. We say Parker brook is “unfit” or sometimes “underfit”. Once however, when the moraines were continuous across this gap, overflows would have caused fast flows, removing the sands but leaving the boulders behind. This is a spillway lag deposit.

Note the current difference in elevation between the bank of the higher meadow and the floor of the lower meadow, at Parker Brook.

Continue along Park Ridge Road. The road climbs out of the Parker Brook spillway and climbs up Augusta Recessional Moraine. Find a place to turn around. Note the White Cedars on this wet end of the meadow.

Return to Rt. 23 North. Travel down the hill. The road cuts have oversteepened the hillside, causing slope failures and giving us good views of the drift. These exposures are (choose: till / ice-contact stratified drift)

Continue to Clove Road above Port Jervis, and then turn left toward Montague, New Jersey. At Y’s we will keep right.

This drive passes many beautiful hills of glacial drift. Near 23 the hills have steep slopes to the north, and gentle slopes to the south. They are called ______.

Further along the drift hills have irregular shapes, and small ponds are sometimes between them. This topography is called ______and ______

(Closed due to Hurricane Sandy damage, we must skip our side trip to the waterfall)

Continue straight to Route 206 at the T in Montague. Turn right onto 206 North, then take the bridge over the Delaware River. Past the toll, turn south on 209. Continue about 5 miles on 209, past Rt. 739, and turn right into the Dingman's Falls Area. Notice the large rounded boulders in the stream beds and streamside alluvial deposits near Rt. 209.

Continue to the parking lot.

Stop 9 Silverthread Falls, Hanging Valleys

Take the boardwalk to Silverthread Falls. The valley you are in is much larger than the valley of the stream falling from above. Suggest some origins for this waterfall. ______

Return to Rt. 209. Turn left, and drive back to the Milford Bridge at Rt. 6. Cross into New Jersey and

Take Route 206 south (left) towards Culver Lake.

Stop 10. Catastrophic Moraine Dam Failure, and spillway lag.

Culver's Gap is an old water gap through the Shawangunk Formation. It is now dry, so it is a Wind Gap. The opening was blocked by a lateral moraine of the glacier deepening Kittatinny Lake on the next level just north of us. Remnants of the moraine have been splayed down the slope of Culver’s Gap, forming a spillway lag deposit.

Stop 11. Ice Cream

Bibliography

Niering, W.A., (1953) The Past and Present Vegetation of High Point State Park, New Jersey. Ecological Monographs, Vol. 23(2): pp. 127-148

Witte, R.W. and Monteverde, D.H. (2005) Geology of High Point State Park. New Jersey Geological Survey Special Publications.

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