B4: NEW INSIGHTS INTO GLACIAL LAKES VERMONT AND ALBANY
John A. Rayburn
Dept. of Geology
SUNY New Paltz
New Paltz, NY 12443
rayburnj@newpaltz.edu
David J. DeSimone
DeSimone Geoscience Investigations
Petersburg, NY 12138
hawkeye272david@yahoo.com
Amy B. Frappier
Department of Geosciences
Skidmore College
Saratoga Springs, NY 12866
afrappie@skidmore.edu
INTRODUCTION
The first comprehensive study of the proglacial lakes in the Hudson and Champlain Valleys was published by J.B. Woodworth in 1905 (NYSM Bulletin 84). He noted that “Lake Albany doubtless began on the south in the waters standing in front of the retreating ice sheet prior to the opening of the Mohawk outlet of the great glacial lakes to the west. As soon as the ice retreated in the valley to a position north of Albany and the drainage of Lake Iroquois came into the Hudson Valley Lake Albany properly came into existence”. While glacial lacustrine sediments in the Champlain Valley were originally attributed by Upham (1889), Baldwin (1894), Peet (1904), and others to be a separate Glacial Lake Champlain, Woodworth notes that its confines were somewhat larger and proposed the name of Glacial Lake Vermont, and that to the south it was certainly confluent with Glacial Lake Albany as he defined. “The outlet of theses ice-dammed waters at this early stage of confluence across the present divide of the Hudson and Champlain basins is a matter which concerns the interpretation of Lake Albany on the south and is considered in that connection. Lake Vermont may be said properly to have come into existence when in consequence of a local lowering of waters south of Fort Edward a discharge began across a barrier into the Hudson Valley to the south.”
While Woodworth (1905) only described one Lake Albany level, he noted under Lake Vermont that there were the Quaker Springs, Coveville, and Fort Edward levels. Of these, Woodworth stated that “The question of the outlets of Lake Vermont … has not been completely exploited as yet by field work”. The Fort Edward level outlet, better defined by Chapman (1932) as the Fort Ann outlet (see also DeSimone et al., 2008 NEFOP Field Guide Stop “Chapman’s Potholes”), is the only one that truly meets his definition of Lake Vermont. Although Chapman recognized several separate Fort Ann levels, only the lowest of these may actually have been confined north of the Champlain-Hudson divide. Woodworth and later Fairchild (1917), Stoller (1922), and Chapman (1937), suggested that the Coveville level threshold is represented by a channel overhanging the Hudson River near Coveville, NY. There are two significant problems with this hypothesis however: 1) the bedrock that this channel is formed in is generally too soft to have withstood the estimated steady-state discharge of the pro-glacial lake and 2) more recent mapping demonstrates that Coveville level strandlines exist south of this location.

B4: NEW INSIGHTS INTO GLACIAL LAKES VERMONT AND ALBAN

STOP 1. Glacial Lake Warrensburg
Along the upper Hudson between Luzerne and Warrensburg, the bluffs expose fine sand terraces, till, and bedrock. A few locations preserve elevated deltas and varved clays, in horizontal orientation and tilted large-scale slump blocks. Glacial Lake Warrensburg was named and mapped by Miller (1911, 1914), who inferred a single long, narrow ice-dammed glacial lake that integrated lacustrine features from Corinth in the south (Stoller’s 1916 moraine-dammed Lake Corinth) through Warrensburg and into the upper Hudson and Schroon valleys north of North Hudson (Lake Pottersville, Miller 1914), including the Paradox Lake valley east of Ticonderoga. Figure 5 shows Miller’s 1925 general map of the paleo-lake extent (dashed line indicates a Hudson-Champlain ice margin). Lake Warrrensburg must be older than the terrace at the Luzerne ice margin (Hanson, 1977). We infer that Lake Warrensburg flooded the Hudson-Schroon Valley north of Luzerne for a brief ∼few-century period, beginning with the ice blockage around ∼15.3-15.1ka.
Miller (1925) reports a graduated level of lacustrine deltas and sand plains, from 208 masl at Corinth to 300 m at Deadwater Pond about 110km to the north. He gives a slope estimate for the entire lake of 4.5 feet per mile, or about about 1 m/1.16 km. Miller locates the lake outlet between the ice and the Palmertown range highland pass “cut by a stream of large volume” near South Corinth. When the ice front retreated past Corinth into the Lake George valley, the upper Hudson outlet eroded below 194m, shifting flow to the east at Corinth through the Hudson valley into Lake Albany, or down the Kayaderosserass to the Milton delta. Lake Warrensburg presumably drained by ∼14.7ka to 14.8ka, during retreat of the ice blockade in the Bølling-Alleröd.
In 2011-12, 2015-16, and 2017-18, undergraduate teams in Amy Frappier’s Honors Paleoclimatology Practicum course have investigated GL Warrensburg varves using a series of short Ridge-style cores from a horizontal varve deposit overlain by a flat massive fine sandy unit several meters thick. The overlying unit is very silty, coarsening-upwards, and contains a kettle bog. Recent field observations of the varve deposits in this area by R.H. Lindemann, Frappier and students, and John Rayburn, indicate that varves can be found in protected locations in the upper terraces, along the banks of the Hudson, and into the river channel. The varve deposits form characteristically steep slopes, and are prone to slumping where undercut by stream incision. Our discontinuous varve cores from our upper terrace site reveal large ∼10cm-scale and small ∼1-2cm-scale varve sequences (Brill et al., 2012; Nolan et al., 2018). At least one low-sedimentation rate period a few decades in length occurring between ∼1-decade-long intervals when annual deposition was higher (Khan et al, 2016). The data are insufficient to determine whether this general sequence relates to glacial melting directly, or to hydro-climate fluctuations at regional or watershed scale that may integrate glacial melting and postglacial sedimentary redistribution processes. Longer, more continuous varve records from this and other sites in the lake basin may help to resolve this and other questions related to deglaciation of the upper Hudson Valley.
Rock flour, silt, and fine sand deposited in Lake Warrensburg was most likely sourced, at least in part, from valley glacier outwash in the adjacent Adirondack highlands, rather than solely from the Laurentide ice sheet. This suggests that GL Warrensburg varve sequences are likely to reflect high-altitude local conditions in the upper Hudson/eastern Adirondack region, particularly in the southern and western Hudson parts of the paleo-lake basin. Whether these varve sequences can be successfully cross-dated to the NAVC remains to be seen, but recovering longer sequences are essential (Nolan et al, 2018). Varves in the tilted slump block (Fig. 6 above) provide a promising target for future work, and additional field scouting further north may reveal additional sites where varves are preserved, including sites with the potential for local pro-glacial conditions that may be sensitive to larger-scale
Laurentide ice dynamics. The differing sensitivities of the southern/western and northern/eastern reaches of Glacial Lake Warrensburg present opportunities for future investigations of this interesting interval of deglaciation in the eastern Adirondacks.
En route to Stop 1, we pass by a typical elevated sand terrace in Warrensburg at ∼720 ft (Fig. 7). Stop 1 offers roadside access to a Lake Warrensburg delta perched on the Western flank of the Hudson Valley. Topset beds with rounded river cobbles evident in the upper section are mostly obscured by grain flows down the exposed section. The delta clearly exposes tilted foreset beds (Fig. 8). Their southerly dip indicates flow from up-valley, rather than from a lateral tributary. Known varve exposures found below the sand unit outcrop just 1km downstream on the eastern side of the Hudson in the lee of a river bend, but are not accessible by car. Split varve cores will be available for inspection along with the exposed delta, as we discuss the emerging picture of how Lake Warrensburg fits into the regional deglaciation history.

STOP 2. The Cove at Coveville
Woodworth suggested that the fully prograded Batten Kill delta into the Hudson Valley may have dammed lower lake levels, forcing discharge through the uplands onto the western uplands (Fig. 2). The flow would therefore have been forced between Bacon Hill and Northumberland and across a divide into the Fish Creek channel at Grangerville (Fig 9). From there it would follow the channel to Victory Mills, but then continue southeastwards and re-enter the Hudson Valley at the rock ledge at The Cove. His justification for this morphology is that “The cove at Coveville in its relation to this hanging valley shows clearly that a large stream at one time flowed southward over the wall of the gorge at this place into the main gorge of the Hudson river, and was arrested after a slight amount of cutting had been accomplished”. Chapman (1932) sites Woodworth (1905), and further states that “At Coveville, where the southern end of this channel overhangs the Hudson River by more than a hundred feet, is a rock ledge which acted as the controlling threshold for the waters during the Coveville stage of Lake Vermont”.
There are several circumstances which strongly argue against the Coveville threshold being located in any part of this channel, however. The primary observation is that no part of this channel is at the Coveville elevation level. The highest modern divide elevation just off Grange Hall Road correlates to the highest Fort Ann level (Fig 3), and The Cove incision is only a little lower than the lowest Fort Ann level. Secondly, the bedrock type along the channel path is not sufficiently strong to have held up to steady state Coveville phase discharges. While some rock at the northern end of the channel is allochthonous (Starks Knob, for example), the primary rock type through the rest of the area is a weak shale that demonstrates significant incision in equilibrium with modern base level and discharges. Since the Coveville stage remained constant and steady for hundreds of years until the catastrophic discharge associated with the breakout of Lake Iroquois at Covey Hill, the threshold for this lake must be elsewhere. The formation of Woodworth’s channel was more likely caused quickly by lake levels falling below the Coveville level with abandonment occurring as the discharge more easily cut through the Batten Kill delta and lacustrine deposits in the main Hudson channel. The Cove itself may just be an abandoned meander bend formed by Fort Ann level discharge through the valley.

STOP 3. Batten Kill Delta
One of the most well preserved deltaic landforms can be seen where the Batten Kill joins the Hudson River across the valley from Schuylerville. An excellent road traverse is to follow Rte 29 east from Schuylerville. Once across the Hudson River, the road rises moderately and climbs from bottomset beds through foreset beds to a large, delta topset flat. Minor drainage ditch exposures reveal the sediment of the delta that generally fines upward and reflects the pro-gradational nature of the landform. In 2008, the FOP trip (DeSimone et al., 2008) visited an active sand and gravel pit in the topsets and upper foresets but that pit is now long closed and well vegetated. A walking traverse along Windy Hill Road would give students an opportunity to follow the delta fore-slope and examine the sediment in drainage ditches.
An altimeter determined elevation of the topsets places them at 96m (315ft) correlating to the Coveville lake level (Fig. 3). Woodworth first recognized this beautiful delta does not fall on a Lake Albany water plane. Subsequent detailed surficial mapping by DeSimone confirmed Woodworth’s placement of the delta on a lower lake level. The important factor here is that Woodworth first had the foresight to recognize a major delta was correlative to a lake level lower than Albany. A short distance farther east in Greenwich there is a remnant of a higher deltaic surface that records deposition in a 115m (380ft) lake, a level that would place it on an Albany II water plane. This is the highest deltaic surface recognized from mapping along the Batten Kill and it does not fall on the highest level of Lake Albany as correctly noted by Woodworth. Either a higher delta has been removed by erosion or Lake Albany lowered before ice retreat opened the Batten Kill valley.

STOP 4. The Saratoga National Historic Park (Lunch Stop)
The short drive from Route 4, the old Colonial river road, up along the Kroma Kill to the park visitors center basically followed a transect perpendicular to the river. We went from flood plain alluvium up through a thick deep water glaciolacustrine clay section deposited in Glacial Lake Albany at its different levels. The fine grained lake silt and clay is capped along the flat river bluffs by a thin layer of lake sand deposited in the shallower waters of the last true lake in this section of the valley, Lake Coveville. We ascended to the gently rolling terrain at the top of the road where we parked and are in an area of generally thin till with rock outcrop.
Your vista from the terrace and lawn of the visitors center embraces a wonderful perspective across the Hudson Valley that is the consequence of both pre-glacial bedrock erosion that established the general geomorphology and Pleistocene glacial erosion and deposition that left the valley infilled with sediment (Fig. 10). Subsequent Late Pleistocene and Holocene erosion carved into the sediment and bedrock and left the landscape we see today.
The underlying bedrock topography and the more obvious glacial geomorphology were responsible for the terrain over which the 2 Battles of Saratoga were fought in September and October 1777. A single image is provided here to summarize the impacts of the geologic history on the battles (DeSimone 2016) and both bedrock and surficial geologic maps of the 4 quadrangles encompassing the SNHP will be available to view and discuss during lunch (DeSimone 2015a, 2015b). The maps are digitally published and those interested in the data layers can find them from the National Park Service and/or see the notations at the bottom of both maps.
The generation of the two maps is the result of a long, eight-year desire that finally came about in 2014- 2015. DeSimone represented the Vermont Geological Survey at a two-day meeting held at UMass in 2007 to discuss the status of mapping in regional Park Service properties. Bruce Heise and Tim Connors represented the National Park Service (NPS). When the SNHP came up for discussion, DeSimone volunteered that most of the park had already been mapped by students of Bob LaFleur during the late 1970s. Eric Hanson (1977, 1980) mapped in the Mechanicville, Schaghticoke and Quaker Springs quadrangles, Jack Dahl (1978) mapped in the Mechanicville and Schaghticoke quadrangles, and DeSimone mapped the Schuylerville quadrangle (1977, 1985). DeSimone suggested it should be an easy task to finish a map of the park. Fast forward to late 2014; Bruce and Tim contacted DeSimone to see if he was interested in doing the project. However, the surprise was they wanted a map of the 4 quadrangles, not just the park and there were little funds to do much, if any field work (Fig. 11). In early 2015, they indicated they also wanted a bedrock map of the 4 quadrangles. The result is the 2 maps you have to view. Both maps largely represent compilations with editing on DeSimone’s part. Meshing the surficial maps together and field checking the contacts consumed nearly all of the allotted field time. Map units were re-designated in an updated fashion with some compromises and simplifications for clarity. Both printed maps were intended to be wall hangers for the SNHP staff and the text on the maps was intended to be educational to the non-geologist.
The bedrock map is work by Kidd, Plesch, and Vollmer (1995), Rickard (unknown date), Landing et al. (2003), Fisher et al. (1970), and a beautiful hand colored map of the Schuylerville 15-minute quadrangle attributed by Rickard to Reudemann (unknown date). My role was to compile and edit the data, merge and extrapolate contacts and convert map units in older terminology to those of Kidd et al (1995). DeSimone chose to add pre-glacial bedrock channels to this map using data from Dineen and Hanson (1983) and Bruehl (1969) with extensions from both data sources.
The lunch view has the gently rolling to sloping till terrain of the visitors center giving way to the clay flats that were farm fields in 1777. The park has tried to maintain the vegetative cover as close to what it was during 1777. The Hudson Valley Lake Albany shoreline is both in the near distance and in the middle distance across the valley where the land slopes up abruptly into the Taconic highlands with the highest summit in view being Willard Mountain, a local ski area. That break in slope approximates the Lake Albany shoreline and follows Route 40 where we’ll drive after lunch. The track of Route 40 also largely coincides with the trace of the Taconic Frontal Thrust or TFT as seen on the bedrock map. On a clear day, the view extends into the far distance where the summit ridge of the Green Mountains is visible.

STOP 5. Hoosic Delta
The Hoosic River and the Batten Kill are two large Hudson River tributaries that drain the Taconic Mountains along the east side of the valley. From the Batten Kill, we proceeded south along Rte 40 following the shoreline of Glacial Lake Albany and also largely following the trace of the Taconic Frontal Thrust or Emmons’s Line. A very distinct lowland to upland break in slope is present.
We continued south to the junction of Rte 40 and Rte 67W and turned west to head back toward the Hudson River. We drove across several of the four readily distinguishable deltas of the Hoosic River deposited into different glacial lake levels. Each succeeding delta breached the older, higher delta. The expression of the deltas as landforms is harder to discern. However, this trip stop lets you see some deltaic sediment stratigraphy. There are two pits across the road from each other and at the time of this writing, we cannot know for certain which pit we can get access to on the day of the trip. Both pits are fairly small and if they are working in them, there will be no permission granted.
The sediment exposed is largely medium to fine sand with predominantly horizontal thin beds, some ripple laminations and no evident ice contact deformation. The sand beds are overlain by variably thick pebble gravel beds with medium to coarse sand. The pebble gravels are cross bedded with some cut and fill structures. The pebble gravels truncate the underlying sand beds. At the smaller pit on the north side of Rte 67, the gravel beds are thin and some of the topsoil has been removed from the exposed face. The original thickness of the gravel facies cannot be determined. At the larger pit on the south side of Rte 67, the gravel facies appears to be intact in the high wall of the pit beneath the more mature vegetation. Here, the pebble gravel facies is approximately 2m thick.
The elevation of the flat top of the landform in the south side pit is 107m (350ft) using the topographic map spot elevation. The pit has been excavated into an isolated terrace within the 107m (350ft) Hoosic delta (Fig. 3). The north side pit was excavated into a lower 98-99m (325ft) Hoosic delta. The largest preserved fragment of the Hoosic deltas has an extensive topset plain between the 113-118m (370-390ft) elevations. A lower terrace of the Hoosic River that may be deltaic lies at 82m (270ft).

STOP 6. Speigletown Kame Moraine and Strandline
This large pit with multiple open excavations exists in the Speigletown kame moraine-kame terrace (Fig. 12). The entrance to the operation is from NY Rte 40. Route 40 follows the old Mahican Indian trail later used as a Colonial coach road. The road generally follows the eastern shoreline of Glacial Lake Albany. Along this route from the Batten Kill south to the Hoosic River and continuing south to the pit, your drive follows the glacial lake shoreline. The shore face is sometimes veneered with beach sand overlying finer grained sediments. The Fane pit began decades ago at the road level. The landform is a kame terrace here that caps bedrock sometimes visible in deeper excavations. Across the road from the pit entrance, shale bedrock is exposed. The depositional environment was that of a classic kame terrace deposited between the Hudson-Champlain ice and the valley wall. The deeper parts of the pit reveal sedimentation from subglacial meltwaters that represent an esker distributing sediment into a subaqueous fan. There are remnants of ice contact sand and gravel deposits that can be seen north of Rte 142, west of Rte 40 and continuing down to toward the Hudson River in Pleasantdale. However, these are not shown on the 1963 surficial map of Schock. Mr. Fane reports hunting along trails leading down to the river and finding a large area of gravel buried by the silt-clay. In contrast, the kame terrace likely received sediment from a meltwater and meteoric water stream following the ice margin. Indeed, some of the sediment may be from the Hoosic River to the north as ice still blocked the river outlet.
Beach sand and even pebble gravel caps the sequence and will be our first vantage point in the pit along the power line. There is a pocket of silt-clay below the beach berm that may represent a small pond behind a sand spit. This is one of the finest sections of Lake Albany beach preserved in a still rural setting. Look across to the road bordering the south face of the pit and you can see the beach profile. The berm here is exceptionally high and this appears to be a natural feature, not built up at all for the power line construction.
Wander to the deepest excavations in the pit. Excavations have reached bedrock at least locally capped with a veneer of till. Ground water seeps out along the base of the gravel and sand as further downward infiltration of ground water is inhibited by the comparatively impermeable till and bedrock. The deeper portions of the pit reveal subaqueous fan sand and gravel. Previously, we could observe arched anti-form bedding from a classic esker. Finer grained lacustrine sediments have an on-lap relationship to the ice contact sediments indicating the quieter water facies were deposited after retreat of the ice removed the source of the proximal gravel and sand facies. One can think of the subglacial meltwater source as a fire hose discharging water and sediment from beneath the glacier into the bottom of Lake Albany. The point source of sediment deposits coarse grained sediment in one locale while adjacent areas have finer grained sediment. The fire hose analogy works if you think of the hose spraying sediment first in one direction and then in another.
We’ll work our way up section toward the east where the sediment is interpreted to have been cascading from the kame terrace environment into the deeper lake waters. Slope instabilities and debris flows must have been common. At any given moment, the pit face may show soft sediment deformation, load deformation and evidence of subaqueous sediment flows. Nearshore sediments in the higher parts of the pit truncate and overlie an ice contact facies composed of interbedded gravel and sand with typical ice contact deformation.

STOP 7. Boulder Moraine and Lag Terrace in Ballston Creek Channel at Shenantaha Creek Park
This last stop takes us to the Shenantaha Park on the Round Lake quadrangle that was most recently mapped by Hanson (1977b). A possible alternative to the Fish Creek/Coveville channel as a threshold and discharge channel for the Coveville level is a drainage divide at East Line between the Morning Kill, Drummond Creek, and Ballston Creek. Besides being at an elevation consistent with the Coveville level it would provide a threshold and drainage network that would effectively control the Coveville level if the main Hudson Valley were dammed between Speigletown and Halfmoon (Fig. 2). This network together with the Ballston Lake channel is all part of the Mohawk distributary channel network and may have been earlier formed in equilibrium with both northward discharge from the IroMohawk as well as southward discharge from glacial Lake Warrensburg. Early investigation of this system was published by Stoller (1911) who inferred that: “A flood of waters once swept northward through Ballston channel, dividing in the vicinity of East Line into three currents which pursued the several courses described above. The time in glacial history when this took place was subsequent to the general disappearance of the ice and also subsequent to the stage of maximum development of Lake Albany” (Fig 4). Stoller (1916) recognized the southern end of a lake that he named Lake Corinth that the Hudson River drained via Kayderosseras Creek southward into Lake Albany forming the Milton delta (Fig. 13). However at 125m (410ft) it is significantly above the Albany water plane (Fig 3) and may actually represent a separate higher-elevation ice marginal lake.
The much larger extent of Lake Corinth was recognized by Miller (1925) and renamed Lake Warrensburg (Stop 1), and that its existence must have been caused by ice damming the modern Hudson channel east of Corinth. It is possible that when the ice was farther south than depicted in Figure 13 the western region of the Hudson Valley including Milton and the distributary channels was confluent with a higher elevation glacial lake in the Mohawk Valley. Northward recession of the ice margin would subsequently drain this lake to Albany level allowing Mohawk Valley discharge directly into Lake Albany through the distributary channels. Eventual ice margin retreat to Glens Falls would open the modern upper Hudson channel to Lake Albany completely draining Lake Warrensburg.
For the distributary channels to form the threshold and drainage route for the Coveville level around the Speigletown moraine (Fig. 2) they would require flow southward through the Morning Kill and/or Drummond Creek channels, and/or westward drainage through the Ballston Creek channel to Ballston Lake to the Mohawk Valley. This would in turn necessitate that the IroMohawk flow directly eastward to the Hudson Valley through its modern channel at Cohoes rather than the distributary channels. It would also necessitate a bedrock exposure of significant strength to withhold steady state discharge from Lake Coveville. These conditions lead to a series of problems. First, like Woodworth’s proposed Coveville outlet, the local exposed bedrock is a weak shale/greywacke mélange that demonstrates easy incision to base level even under modern discharge conditions. Second, like Stoller, we observe no southward flow indicators in the channels and only very strong eastward flow indications in the Ballston Creek channel. This includes an imbricated boulder terrace (also recognized by Stoller, 1911) near the head of the Ballston Creek channel that could only have resulted from strong eastward flow towards Round Lake (Fig. 14).
On the positive side, however we have evidence that the IroMohawk must have been flowing directly eastward through the modern channel at least at the very end of the Coveville Phase. As stated in the introduction, the base level for Cohoes Falls which clearly migrated back through the shale-rich mélange from the Hudson Valley is at Hudson River level, and that discharges only on the scale of the IroMohawk could have caused this knick point migration. This now under-fit falls is apparently frozen in time with the reversal of drainage of Lake Iroquois at Lake Iroquois into Lake Vermont causing it to drop from Coveville level to Cobblestone Hill and Fort Ann levels (Rayburn et al., 2005; Franzi et al., 2007; DeSimone et al., 2008; Franzi et al., 2016). Interestingly there are a number or terraces carved into the shale of the Ballston Creek channel ranging in elevation from Coveville level at the head of the channel Shenantaha Creek Park near East Line down to through the Fort Ann levels and below to the east, suggesting that this channel was at baseline equilibrium with Lake Albany and Lake Vermont (Fig 15). Also the imbricated boulder moraine surface along the creek at the edge of the park correlates to Cobblestone Hill level, suggesting that it may have been the Lake Iroquois breakout flood that caused the lagged surface in the boulder moraine and that flow was eastward into the Hudson Valley at this location.