RUSSELL L. LOSCO

SOUTHEASTERN GEOLOGYV. 47, No.2, May 2010, p. 85-94

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ABSTRACT

This study documents a paleosol impact-ed by periglacial features at a site on the Del-marva Peninsula of Southern Delaware. Thispaleosol is characterized by increased stiff-ness/density, change in matrix color, evi-dence of induration and cementation, relictfluvial versus aeolian sedimentary struc-tures, secondary structures associated withpermafrost or deep seasonal frost, and fossilroots and animal burrows. Partially-lig-nitized roots, root channels, animal burrowsand secondary sedimentary structures asso-ciated with subaerial exposure and soil-forming processes truncate abruptly at thecontact with the overlying massive, loose, ae-olian sand. We hypothesize that this paleosoldeveloped within fluvial beds of the Beaver-dam Formation during a lengthy period ofsubaerial exposure. Several layers of parentmaterial of different origins were noted: a)structureless clays, b) structureless aeoliansands, c) fluvial, normal-graded, cross-strat-ified, and laminated sands with gravel lagbeds, and d) indurated, sandy clays inter-preted to be a paleosol. Sufficient definitionof the surface of this paleosol was obtained to

reconstruct the paleotopography of the site,which is distinctly different from the currenttopography. We interpret this buried surfaceas a former land surface of early Pleistoceneto late Pliocene age.

INTRODUCTION

Recent investigations have documented thepresence of periglacial features on the EastCoast of the United States farther south thanpreviously thought. The objective of this studywas to investigate landforms and subsurfacefeatures on the Delmarva Peninsula to deter-mine if they support the presence of a perigla-cial paleoenvironment as far south as SouthernDelaware. Although late Wisconsinan glaciersin Pennsylvania were considered to be separat-ed from evergreen woodlands by no more than100 km of tundra, recent data indicate that with-in the coastal plain of New Jersey and Dela-ware, sandy, well-drained, poorly-vegetatedsoils may have allowed tundra conditions to ex-tend farther south than formerly thought.French and Demitroff (2001) state that theclosed depressions commonly found on theCoastal Plain (sometimes referred to as “Caro-lina” basins) are considered to be deflation hol-

PERIGLACIAL FEATURES AND LANDFORMS OF THE DELMARVA PENINSULA

RUSSELL L. LOSCO

Lanchester Soil Consultants, Inc.311 East Avondale Road

West Grove, PA, USA, [email protected]

WILLIAM STEPHENS

Stephens Environmental Consulting, Inc.P.O. Box 485

North East, MD, USA, [email protected]

MARTIN F. HELMKE

West Chester UniversityDepartment of Geology and Astronomy

207 Merion Science CenterWest Chester, PA, USA, 19393

[email protected]

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RUSSELL L. LOSCO, WILLIAM STEPHENS AND MARTIN F. HELMKE

lows or blowouts formed by strong katabiaticwinds originating from the glaciers to the north.These aeolian activities appear to be a signifi-cant force in the formation of the landscape.Sand wedges or sand-wedge relicts are de-scribed as examples of deep frost action. Cryo-turbated soils and polygonal patterned groundare also noted as evidence of periglacial condi-tions.

Andres & Howard (1998) report wedge castsin the Scotts Corner Formation at the PollackFarm site in Delaware. They interpret thewedge casts as fossil frost wedges formed inseasonally frozen ground based upon down-ward warping of adjacent beds.

Investigations of sites in the New Jerseycoastal plain indicate that late Pleistocene per-mafrost extended as far south as 39° north lati-tude. Wedge casts, referred to as groundwedges, found in the area are interpreted as sea-sonal frost cracks infilled with loose aeolianfrosted sands. Optically-stimulated-lumines-cence (OSL) dating of the infilled material indi-cates that the sands accumulated during twoseparate periods, one during the late Illinoian toearly Wisconsinan glaciation (55-66 ka) and an-other during the late Wisconsinan glaciation(15-22 ka). Based upon the thermal contractioncracking in fine and coarse-grained sands,French et al. (2003) postulated that maximummean annual air temperatures of <-4 and <-8 °Cwere common. Dislocation of near-surfaceironstone deposits suggests that permafrost inthis area reached thicknesses of 10-15 m(French et al., 2003).

Wedges filled with aeolian sand have beendocumented at two locations in New CastleCounty, Delaware at approximately 39° 44’ and39° 25’ north latitude within the Columbia For-mation. The Columbia Formation is composedof fluvial sands that accumulated approximate-ly 400 ka with a surface discontinuity that iscapped by loess that accumulated approximate-ly 10 to 13 ka. Pollen assemblages indicate thatthe Columbia Formation accumulated during atransitional period from a cold, glacial stage toa warmer, inter-glacial period. The wedgesfound are consistently below the loess cap andtherefore pre-date the last glacial maximum and

are morphologically consistent with the pres-ence of permafrost. A number of other featuresassociated with cold-climates, including dunes,sand sheets and shallow depressions noted inthe area, are considered to have formed duringthe coldest part of the Wisconsinan glaciation(Lemke et al., 2004).

The generally-accepted origin of groundwedges or ice-cast wedges in the coastal plain isthermal contraction of perennially-frozenground with cracks infilled with aeolian sandsfrosted and deposited by strong katabiaticwinds. Modern analogs in high latitudes indi-cate that surface soil temperatures may havebeen in the -15 to -20 °C range when this crack-ing occurred. OSL dating of sands infillingthese cracks and forming the wedges suggest atri-modal formation chronology with wedgesforming at >147 ka, again at 50 to 70 ka and amore recent set at 13 to 35 ka. These ages sug-gest wedge formation of probable Illinoian, ear-ly Wisconsinan and late Wisconsinan age. Thelate Wisconsinan episode likely followed theLast Glacial Maximum (LGM) and may not beassociated with significant ground ice growth.It is thought that the post-LGM episode wascharacterized by thin or discontinuous perma-frost or deep seasonal frost. The late Pleisto-cene-Holocene transition has been described tohave been a time of significant aeolian activitydominated by braided fluvial systems with theformation of dunes and deflation hollows on

Figure 1. Site Location. The site is located onthe Delmarva Peninsula, in the Coastal PlainPhysiographic Province of the Mid-AtlanticRegion in Sussex County Delaware at approx-imately 38° 42’ North Latitude and 75° 30’ WestLongitude.

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PERIGLACIAL FEATURES AND LANDFORMS

upland surfaces (French et al., 2007). Murton et al. (2000) discuss the formation of

wedge structures by infilling of thermal con-traction cracks or ice wedges. These cryogenicsand wedges are reported to occur widely in po-lar desert and tundra. The fill in these wedges isreported to be either massive or laminated andmay contain pebbles and inclusions of the sur-rounding parent material. Large wedges ex-ceeding 2 m in depth are interpreted as beingevidence of continuous permafrost. Manywedges are reported to have been morphologi-cally modified by post-depositional forces suchas loading, slope-related movement, glaciotec-tonic deformation or frost heaving.

Markewich et al. (2009) report parabolicdunes of aeolian origin on the west shore of theChesapeake Bay that have their origins in theWisconsinan glaciation. They report a recentepisode of significant aeolian deposition thatcoincides with the period of major growth in theLaurentide Ice Sheet between 35 and 15 ka.Three or more intervals during this time periodsaw wind as the dominant geomorphic agent inthis region. Each of these episodes are reportedto have followed rapid incision into crystallinebedrock by the Potomac and Susquehanna riv-ers between 35 and 30 ka, which would haveprovided significant quartz as raw material forthe deposition of sand across the region.

Periglacial features have been recognized inthe northeastern United States for some time.Boulder rings, boulder stripes and rubble onridge tops are reported in northern Pennsylvaniaand described as being a result of deep seasonalfreeze and thaw during early Wisconsinan gla-ciation. Estimated frost depths were within 2 to3 m at the time of formation of these features(Denny, 1951). Clark (1968) described sortedpolygonal pattern ground at high elevations inPennsylvania, West Virginia and Virginia as be-ing periglacial in origin. These features are eas-ily compared with modern analogues at highlatitudes, such as those noted in the Devon Pla-teau of Nunavut in Canada (Ugolini et al.,2006).

Quaternary paleosols in the Arctic that wereexposed during glacial periods exhibit relictcryogenic features including sand wedges, ice

wedge casts, sand involutions and cryoturba-tion. Holocene soils in the same area exhibitpatterned ground as the most common relictfeature. The Wounded Knee Paleosol in thecentral Yukon, found at elevations of less than1000 m is considered to be of early Pleistoceneorigin. This paleosol is strongly weathered andrubefied and exhibits a paleoargillic Bt horizonwith thick argillans as well as sand wedges, icewedge casts and ventifacts. Patterned groundand stone circles are also reported. Taarnocai &Valentine (1989) reported that the rubeficationexhibited requires a mean annual air tempera-ture (MAAT) of >7 °C. As this area now has aMAAT of -5 °C, the rubefication is interpretedas being relict.

In northwestern Europe, common Quaterna-ry periglacial features include ice-wedge casts,cryoturbation and patterned ground. Intergla-cial paleosols commonly exhibit weaklyrubefied argillic horizons that are thicker andmore enriched in illuvial clays than thoseformed in the Holocene. Expulsions of air bub-bles during thawing are thought to producelarge rounded or mamillated pores or vesicleswithin these paleosols. Quaternary alterationsof glacial and interglacial sediments could bestronger in the middle latitudes, resulting in rel-ict features that are more widespread (Catt,1989). Permafrost degradation is reported toproduce thaw consolidation and liquefactionthat contributes to a compacted layer at the levelof the paleo-permafrost table (French et al.,2009). Paleosols such as these can provide in-formation on past climatic histories. Investiga-t i o n s o f l o e s s - p a l eo so l s e q u e n c e s i nSoutheastern Central Europe and Central Chinahave provided detailed climatic information onportions of the middle and upper Pleistocene.These interpretations must be made carefully,however, as many paleosols are truncated(Bronge and Heinkele, 1989).

Based upon this growing body of informa-tion, it is not unreasonable to expect to find ev-idence of periglacial impact on sites farthersouth than previously documented. The objec-tive of this study was to identify and documenta paleosol and landform features and to deter-mine if their origin is periglacial.

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REGIONAL SETTING

The site is a 53 hectare (130 acre) tract ofland located in Sussex County, Delaware, Unit-ed States of America at approximately 38° 42’North Latitude and 75° 30’ West Longitude(Figure 1). The site is located on the DelmarvaPeninsula, in the Coastal Plain PhysiographicProvince of the Mid-Atlantic Region. The sitewas a fallow farm field dominated by weedsand surrounded to the north by a young, man-aged Loblolly pine forest.

Topography is gently rolling, concavo-con-vex and has very little topographic relief. Eleva-tions in the area range from less than 10 m

above mean sea level (MSL) along streams tomore than 18 m above MSL at Wilson Hill tothe northeast of the study areas.The surfacedrainage is primarily accommodated by drain-age ditches and channelized streams. The site ispunctuated by undrained depressions. The sitelies along the drainage/watershed divide be-tween the Chesapeake Bay and the DelawareInland Bays watershed. The site is mapped asbeing underlain by unconsolidated fluvio-ma-rine sediments of the Pliocene Age BeaverdamFormation (Ramsey, 2008), which overlay Mio-cene estuarine and marine sediments of theChesapeake Group (Groot and Jordan, 1999).

Table 1. Profile log for test pit 1411 described using the USDA system. The Ap and C horizonsconsist of loose and relatively structureless aeolian sands overlying the surface of the paleosol(2Btg horizon) and lower horizons of varying parent materials. Note the change in consistencystarting at the 2Btg horizon and continuing with depth. The plasticity of the 2Btg horizon and thefirmness and massive structureless condition of the 3Btg and 4Cg horizons could indicate com-paction due to consolidation and liquefaction from degradation of permafrost. The 4Cg horizonis cemented.

HorizonDepth

in inches

Matrix Color Texture Structure Consistence Boundary

Redox Feature Color

Redox Feature

DescriptionNotes

Ap

0-12 2.5Y4/2 medium sandy loam

coarse weak subangular blocky

very friable clear smooth

C

12-27 2.5Y8/4 medium loamy sand

single grain structureless

loose clear smooth

2Btg

27-32 10YR5/6 medium sandy clay-loam

medium weak suban-gular blocky

slightly plastic abrupt smooth

3Btg

32-56 Varie-gated N6/ & 5R5/6

clay medium strong sub-angular blocky

extremely firm abrupt smooth

N6/ matrix

4Cg

56-72 Varie-gated N8/ & 7.5YR6/8

medium sandy loam

massive structureless

extremely firm gradual smooth

N8/ matrix cemented

5Btg

72-97 Varie-gated 5PB8/1 & 7.5YR5/6

clay-loam


plastic clear smooth

5PB8/1 matrix old lignitic roots to 97"

6Cg

97-105

Varie-gated 10YR7/1 & 10YR5/8

fels-pathic heavy medium sandy loam


friable

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MATERIALS AND METHODS

A preliminary reconnaissance phase consist-ing of 32 hand auger borings to a depth of 1.5-2.0 m was conducted using a grid pattern of 100m across the site. The reconnaissance phase wasfollowed by intensive, high-definition soil andhydrogeologic mapping of two areas within theproperty. The detailed mapping included exca-vation and examination of 32 backhoe pits to 4-m depth and over 325 hand auger borings atdepths of 1.5 to 2.0 m on a 23-m grid patternacross the areas. The soil mapping was coupledwith hydrogeologic mapping that included 33deep probes using a direct-push rig with contin-uous sampling to depths of 7 to 15 m, as well as32 deep hand auger borings completed with 5cm diameter PVC observation wells and 11shallower wells within the vadose zone. Soil

profiles were logged using the USDA andUSCS systems. Surface topography and allsample locations were surveyed in DelawareState Plane Coordinates using a combination ofa survey-grade global positioning system (GPS)and conventional survey techniques allowingcontrol of both physical locations and topogra-phy.

RESULTS AND DISCUSSION

Early examination of the soils exposed in thebackhoe pits revealed that the subsurface stra-tigraphy of the study site was significantly morecomplex than anticipated based on soils andgeologic maps previously published. One soilprofile (Table 1) exhibited six different sets ofparent materials. The surface soils consisted ofrelatively structureless sandy loams and loamy

Figure 2. Test pit 1411 showing the distinct boundary between the paleosol and the overlyingstructureless aeolian sands.

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sands that include small sub-rounded gravelsoverlying the paleosol, which was composed ofslightly rubified and, in some cases, gleyed san-dy clayloam. The lower horizons included par-ent materials of apparent structureless clays, lagdeposits of possible aeolian pavement, fluvialtrough and planar cross-stratified sands, andlaminated fine to very fine sands in normalgraded sets 30 to 60 cm thick, often truncatedby the overlying set of beds (Figure 2). As thepaleosol was encountered in nearly every testpit and auger boring, it became a focus of the in-vestigation as it appeared that it could signifi-cantly impact subsurface water flow within thevadose zone.

The paleosol was readily recognized in bothauger borings and test pits based upon colorchange, textural change, and induration. Subse-quent infiltration testing indicated that the per-meability of the paleosol was roughly 30% thatof the overlying sands. Double ring infiltrome-ter (ASTM standard D3385-94) testing yieldedan average infiltration rate of 15.86 cm/hr forthe shallow soils and 4.62 cm/hr for the paleo-

sol. This dichotomy in permeability rates mir-rors initial estimations based upon soil texture,structure and consistence.

The surface of the paleosol occasionally in-cluded sub-rounded fine gravels of chert thatappeared to be wind abraded. The paleosol wasintersected by a number of features of interest.Two instances of apparent wedge casts were ob-served. The most striking wedge cast (Figure 3)was infilled with a friable, massive, mediumsandy loam that was significantly more oxi-dized than the matrix of the paleosol. The pres-ence of these wedge casts indicate thatperiglacial conditions with deep seasonal frostor permafrost existed in this region at some timein the past. We interpret these wedges to be sim-ilar to the ice wedge casts described by French,et al. (2001, 2003, 2007, 2009) or the cryogenicsand wedges described by Murton et al. (2000).The presence of the gravels at the interface be-tween the paleosol and the surface horizons in-dicate that the surface of the paleosol wasformed during subaerial exposure and was atone time a stable land surface, but experienced

Figure 3. Test pit 1414 exhibiting wedge cast. Material within wedge is friable, massive, mediumloamy sand; surrounding matrix is coarse loam to sandy clayloam.

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Figure 4a. Lignitizedroots are truncated atthe sur face o f thepaleosol.

Figure 4b. Macropores in test pit 1444,which are roughly cylindrical in crosssection. These could be sand wedgesthat have undergone post-depositionalsoft sediment deformation. The resem-blance to rodent burrows, however,suggests that these are krotovina ofanimal origins. Material infilling krotov-ina is composed of friable, massive,medium loamy sand similar to thesands found in the surface horizons.The surrounding matrix is mediumsandy loam to sandy clayloam.

Figure 4c. Macropores of indeterminate origin. Thesemacropores appear to be significant preferential flowpathways allowing groundwater recharge.

differential erosion and loss of all or part of a surfaceh o r i zo n c o n t a i n i n g g r a v e l l y c l a s t s .

Lignitized roots that originated within the paleosolwere found at a number of locations (Figure 4a). Fu-ture studies could include sampling of the roots to al-low for radiocarbon dating. Significant macroporesinfilled with material differing from the matrix of thepaleosol were recognized. The most striking of thesewas a series of 3 to 6 cm diameter macropores thatwere infilled with friable, massive white sands similarmorphologically to the sands found in the surface ho-rizons (Figure 4b). They were truncated at the overly-ing contact with the structureless sands and are

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therefore considered post-depositional andpost-date the development of the paleosol. It ispossible that these features are sand wedges thathave been modified by post-depositional softsediment deformation. The shape, configura-tion and placement of these macropores, how-ever, are reminiscent of rodent burrows. Wehypothesize that these represent the remains ofburrows inhabited by small rodents at the timewhen the paleosol was exposed and that theseburrows were then infilled with aeolian sands asthey were subsequently deposited on the site.We interpret these krotovina to be contempora-neous with the mature paleosol environment ofa warm interglacial or pre-glacial period.

A number of other, less identifiable macrop-ores were recognized in a number of locations(Figure 4c). These macropores, though their or-igins are less clear, are likely significant path-ways for recharge of the aquifer in this area.

The systematic and detailed nature of the in-vestigation with hand auger borings spaced on a23-m grid pattern, coupled with precise survey

location and the readily recognizable paleosol,permitted the preparation of an isopach map ofthe top of the paleosol. Taking the known sur-face elevations at each point on the grid andsubtracting the depth to the surface of the paleo-sol yielded an elevation for the surface of thepaleosol (Figure 5). We assume that this paleo-sol was formed during a lengthy period of sub-aerial exposure, that it was a stable land surfaceat one time and that it was subjected to modifi-cation on a macroscopic scale by alternate peri-ods of freezing and thawing with both windgenerated and fluvial erosion. Our interpreta-tion is provisional, however, and subject to re-finement as additional information becomesavailable. The topography of the existing landsurface and the surface of the paleosol werefound to differ as illustrated in the isopach map.Figure 6 illustrates the difference in the topo-graphic profile across one area of the site.

Figure 5. Isopach map comparing current surface topography (right) with paleo-topography (left).Contours are 1-foot intervals.

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CONCLUSIONS

The nature of the paleosol recognized at thissite indicates that it was formed by a lengthy pe-riod of subaerial exposure followed by modifi-cation under periglacial conditions. Thepaleosol was subsequently buried by aeoliansands following, presumably, the last glacialevent.

Wedge casts indicate periglacial influencesthat could be either permafrost or deep seasonalfrost. Based upon the findings of French et al.,the age of these ground wedges could coincidewith one of the three periods of wedge forma-tion which would place the age of the paleosolsurface at >147 ka, 70 to 50 ka or 35 to 13 ka. Ifwe assume that the paleosol was a stable landsurface, this would place the age of the forma-tion of the surface at a time previous to the lat-est, but most likely the oldest, glacial period. Asthe Beaverdam Formation is dated as Pliocene,it is also possible that this paleosol is of Plio-cene origin.

The significance of aeolian processes as a re-sult of katabiatic winds in the formation of thelandscape of the Coastal Plain has been docu-mented repeatedly by others. The presence ofstructureless sands with a relative lack of signif-icant pedologic development in the surface ho-rizons is consistent with this model. The windabraded gravels found within the sands above

the paleosol and at the surface of the paleosolsupport an aeolian origin for the sands restingon the surface of the paleosol. An aeolian originis consistent with the existing undrained depres-sions on the site that appear to be formed as de-flation hollows. We interpret some of themacropores noted in profiles as the remnants ofanimal burrows. Some other macropores appearto be krotovina of plant origin or of undeter-mined origins.

We suggest the existence of a buried land-scape that pre-dates the glaciations of the Pleis-tocene. We further suggest that this landscapewas formed under a warmer, non-glacial cli-mate during the Pliocene and remained relative-ly stable through much of the Pleistocene. Thisland surface was strongly influenced by perigla-cial processes including permafrost or deep sea-sonal frost during episodes of continentalglaciations as evidenced by wedge casts. Dur-ing interglacial periods, this landscape was veg-etated and inhabited by fauna as evidenced bythe macropores encountered. The land surfacewas repeatedly impacted by aeolian scouring,sedimentation and modification/alteration dueto strong katabiatic winds of glacial origin.These aeolian depositional episodes are likelyresponsible for burying the area under struc-tureless sands which also infilled the wedgesand faunal krotovina creating the gentle topog-raphy that exists today.

Figure 6. Profile of section A – A’ comparing current surface topography with paleotopography.

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REFERENCESAndres, A.S. and Howard, C.S.; Analysis of Deformational

Features at the Pollack Farm Site, Delaware; Geologyand Paleontology of the Lower Miocene Pollack FarmFossil Site, Benson, R.N. (eds). Delaware GeologicalSurvey, Special Publication No. 21, 47-53, 1998.

Bronge, A. and Heinkele, K., Paleosol Sequences as Wit-nesses of Pleistocene Climatic History; CATENA Sup-plement 16, Paleopedology, Nature and Application ofPaleosols, pp. 163-186, 1989.

Catt, J., Relict Properties in Soils of the Central and North-West European Temperate Region, CATENA Supple-ment 16, Paleopedology, Nature and Application ofPaleosols, pp. 41-58, 1989.

Clark, M.G.; Sorted Pattern Ground: New AppalachianLocalities South of the Glacial Gorder; Science, Vol.161, Number 3839, pp 355-356, 1968.

Denny, C.; Pleistocene Frost Action Near the Border of theWisconsin Drift in Pennsylvania; The Ohio Journal ofScience, Vol. 51 (3), May 1951.

French, H.M. and Demitroff, M.; Cold-climate Origin of theEnclosed Depressions and Wetlands (‘Spungs’) of thePine Barrens, Southern New Jersey, USA; Permafrostand Periglacial Processes, Vol. 12:337-350; 2001

French, H.M., Demitroff, M. and Forman, S.L.; Evidencefor Late-Pleistocene Permafrost in the New Jersey PineBarrens (Latitude 390 N), Eastern USA; Permafrost andPeriglacial Processes, Vol. 14:259-274; 2003.

French, H.M., Demitroff, M., Forman, S.L. and Newell,W.L.; A Chronology of Late-Pleistocene PermafrostEvents in Southern New Jersey, Eastern USA; Perma-frost and Periglacial Processes, Vol. 18:49-59; 2007.

French, H.M., Demitroff, M. and Newell, W.L.; Past Perma-frost on the Mid-Atlantic Coastal Plain, Eastern USA;Permafrost and Periglacial Processes, Vol. 20:285-294;2009.

Groot, J.J. and Jordan, R.R.; The Pliocene and QuaternaryDeposits of Delaware: Palynology, Ages, and Paleoen-vironments; Delaware Geological Survey Report ofInvestigations No. 58, 1999.

Lemke, M.D. and Nelson, F.E.; Cryogenic Sediment-FilledWedges, Northern Delaware, USA; Permafrost andPeriglacial Processes, Vol. 15:319-326; 2004.

Markewich, H.W., Litwin, R.J., Pavich, M.J. and Brook,G.A.; Late Pleistocene eolian features in southeasternMaryland and Chesapeake Bay region indicate strongWNW-NW winds accompanied growth of the Lauren-tide Ice Sheet; Quaternary Research, Vol. 71:409-425;2009.

Murton, J.B., Worsley, P. and Gozdzik, J.; Sand Veins andWedges in Cold Aeolian Environments; QuaternaryScience Reviews, Vol. 19:899-922; 2000.

Ramsey, K.W.; Delaware Geological Survey, personal com-munication, 2008.

Tarnocai, C. and Valentine, K.W.G., Relict Soil Properties ofthe Arctic and Subarctic Regions of Canada, CATENASupplement 16, Paleopedology, Nature and Applica-tion of Paleosols, pp. 9-39, 1989.

Ugolini, F.C., Corti, G., and Certini, G., Pedogenesis in theSorted Pattern Ground of Devon Plateau, Devon Island,Nunavut, Canada, Geoderma Vol. 136, pp. 87-106,2006.

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RUSSELL L. LOSCO