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Charles Storrow Denny

Publications and source records attributed to Charles Storrow Denny.

11 recordsLinked to original sources
USGS1979

Upper Cenozoic deposits of the central Delmarva Peninsula, Maryland and Delaware

The surface and shallow subsurface sediments of the lower Delmarva Peninsula include beds ranging in age from Miocene to Holocene. The oldest beds appear to be typical shelf deposits of the Chesapeake Group (Calvert-Choptank age). These marine units are overlain by deltaic deposits, which range from fluviatile facies in the north (Pensauken Formation) to marginal marine and marine beds in the south ('Yorktown(?) and Cohansey(?)' Formations as used by Rasmussen and Slaughter in 1955). This large deltaic mass underlies most of the Delmarva Peninsula. Fossil age determinations supplemented by some radiometric dates indicate the delta to be largely late Miocene in age. The nonmarine facies of the delta, the Pensauken Formation, previously was considered to be Pleistocene in age. The late Miocene delta and possibly the Yorktown Formation (lower to middle Pliocene) are overlain by a feldspathic sand, the Beaverdam, which is at least in part marginal marine. Microflora recovered from this formation include species no longer indigenous to the Delmarva region ('exotics'). On the basis of existing information, microfloral assemblages containing 'exotics' are pre-Pleistocene in age. The Beaverdam therefore is pre-Pleistocene in age, probably late Pliocene. A highly dissected and weathered unit, the Walston Silt, caps the uplands of the central Delmarva Peninsula, where it overlies the Beaverdam. The Walston has a microflora containing 'exotics' and therefore is considered to be the youngest Tertiary unit (uppermost Pliocene) in this area. Sediments forming a barrier-back-barrier sequence fringe most of the southern Maryland-Delaware part of the Delmarva Peninsula and are found at altitudes of as much as 15 m (50 ft) above sea level. This sequence, the Omar Formation, is Sangamon in age and has been dated radiometrically as 60,000 to about 100,000 years old. The microflora in these beds contains no 'exotics,' and the assemblage suggests a warm-temperate environment. The Omar represents the highest stand of the Quaternary seas in the Delmarva region. The Ironshire and Kent Island Formations overlie or cut into the Omar Formation and are probably late Sangamon and middle Wisconsin, respectively, in age. Near Ocean City, the Ironshire forms a seaward-facing scarp with a toe nearly 4.5 m (15 ft) above sea level. A warm-temperate microfloral assemblage from the fluviatile-estuarine facies of the Ironshire Formation in the Delaware Bay region suggests that the formation is interglacial, probably late Sangamon in age. The Ironshire and Omar Formations are overlain unconformably by the Sinepuxent Formation. The top of this marine unit is slightly above present sea level and has been dated by radiocarbon as about 30,000 years old or middle Wisconsin. The microflora from this formation is a cold to cool-temperate assemblage (high proportion of spruce pollen). The outer fringes of the Delmarva Peninsula are being overlapped by deposits of a Holocene marine transgression.

Professional Paper↗
USGS1979

The Parsonsburg Sand in the central Delmarva Peninsula, Maryland and Delaware

The Parsonsburg Sand, a surface sand largely of Wisconsin age, caps terraces east of some of the major streams and mantles broad areas on the uplands of the central Delmarva Peninsula, Maryland and Delaware. The main body of the formation east and south of Salisbury, Md., ranges from 1.25 to 6.00 m (4-20 ft) in thickness and is a medium-grained moderately feldspathic sand containing a relatively mature heavy-mineral suite. The sand is either stratified or massive, and in some areas contains peaty sand and silt-clay, typically at or near the base of the formation. The organic matter ranges in radiocarbon age from about 30,000 to about 13,000 years B.P. and contains microfloral assemblages suggesting that at the time the sand was deposited the climate was cooler and drier that it is at present. The region may have been a pine-birch barrens in which were small ponds, spruce bogs, and abundant shrubs. The distribution of the sand at or near the position of high stands of the Sangamon sea suggests that the Parsonsburg Sand was derived from sandy shore and nearshore deposits of Sangamon age. Deposition was in part eolian and in part fluvial and lacustrine, probably in small streams and ponds between sand dunes.

Professional Paper↗
USGS1979

Sand dunes on the central Delmarva Peninsula, Maryland and Delaware

Inconspicuous ancient sand dunes are present in parts of the central Delmarva Peninsula, Maryland and Delaware. Many dunes are roughly V-shaped, built by northwest winds, especially on the east sides of some of the large rivers. On the uplands, the form and spacing of the dunes are variable. A surficial blanket composed mainly of medium and fine-grained sand-the Parsonsburg Sand-forms both the ancient dunes and the broad plains between the dunes. The sand that forms the dunes is massive and intensely burrowed in the upper part; traces of horizontal or slightly inclined bedding appear near the base. Quartz is the dominant mineral constituent of the sand. Microline is abundant in the very fine to fine sand fraction. The heavy-mineral assemblages (high zircon, tourmaline, rutile) are more mature than in most of the possible source rocks. The most abundant minerals in the clay-sized fraction are dioctahedral vermiculite, kaolinite, illite, montmorillonite, and gibbsite. The first four minerals are common in deposits of late Wisconsin and Holocene age. The gibbsite may be detrital, coming from weathered rocks of Tertiary age. The soil profile in the dune sand is weakly to moderately developed. At or near the base of the Parsonsburg Sand are peaty beds that range in age from about 30,000 to about 13,000 radiocarbon years B.P. Microfloral assemblages in the peaty beds suggest that the dunes on the uplands formed in a spruce parkland during the late Wisconsin glacial maximum. The river dunes may also be of late Wisconsin age, but could be Holocene.

Professional Paper↗
USGS1963

Surficial geology and soils of the Elmira-Williamsport region, New York and Pennsylvania, with a section on forest regions and great soil groups

The Elmira-Williamsport region, lying south of the Finger Lakes in central New York and northern Pennsylvania, is part of the Appalachian Plateaus physiographic province. A small segment of the Valley and Ridge province is included near the south border. In 1953 and 1954, the authors, a geologist and a soil scientist, made a reconnaissance of about 5,000 square miles extending southward from the Finger Lakes, N.Y., to Williamsport, Pa., and eastward from Wellsboro, Pa., to Towanda, Pa. Glacial drift of Wisconsin age, covering the central and most of the northern parts of the region, belongs to the Olean substage of MacClintock and Apfel. This drift is thin and patchy, is composed of the relatively soft sandstones, siltstone, shales, and conglomerates of the plateaus, commonly has a low calcium carbonate content, and is deeply leached. Mantling its surface are extensive rubbly colluvial deposits. No conspicuous terminal moraine marks the relatively straight border of Olean drift. The Valley Heads moraine of Fairchild near the south ends of the Finger Lakes is composed of relatively thick drift containing a considerable amount of somewhat resistant sedimentary and crystalline rocks. Commonly this drift has a relatively high carbonate content and is leached to only shallow depths. The Valley Heads drift is younger than Olean, but its precise age is undetermined. The age of the Olean is perhaps between Sangamon and Farmdale, on the basis of, in part, a carbon-14 date from peat at Otto, N.Y. All differences in soil development on these two Wisconsin drifts are clearly related to the lithology of the parent material or the drainage, rather than to weathering differing in kind or in duration. The authors believe that the soils are relatively young, are in equilibrium with the present environment, and contain few, if any, features acquired during past weathering intervals. The effect of tree throw on soil profiles and the presence of soils on slopes clearly indicate that soils form rapidly. Sols Bruns Acides are the most extensive great soil group occurring throughout the region. Podzols and Gray-Brown Podzolic soils are also widespread, and on long, smooth slopes Low Humic-Gley soils are common. Organic soils are of small extent. South of the Wisconsin drift border, the surficial mantle consists chiefly of alluvial, colluvial, or residual deposits of Wisconsin or of Recent age, but there are many small isolated patches of older, strongly weathered materials of pre-Wisconsin age. Although such older materials are commonly overlain or mixed with less weathered mantle, the yellowish-red color, characteristic of the strongly weathered material, is generally not masked. Some of the older material is drift, presumed to be of Illionian age, that was probably strongly weathered to a considerable depth in Sangamon time and has been greatly eroded since the last interglacial period. No clear-cut exposure of Wisconsin drift resting on older drift or other strongly weathered mantle has been found. The old drift and the other strongly weathered materials apparently acquired their present red color in pre-Wisconsin time. Where exposed at the surface, such strongly weathered mantle is the parent material of modern Red-Yellow Podzolic soils. Sols Bruns Acides and Gray-Brown Podzolic soils, developed on slightly weathered parent materials, are found adjacent to these red soils. This suggests that these Red-Yellow Podzolic soils probably developed from strongly weathered parent materials. No buried soils were found nor were any soils recognized as relics from pre-Wisconsin time. Comparison of a map of the great soil groups with a map of the vegetation of the region, prepared by John C. Goodlett, does not reveal a close relation. Laboratory analyses of samples collected furnish data on textural, mineralogical, and chemical changes caused by weathering and soil formation. The results indicate that the amount of chemical weathering which the Wisconsin drift has undergone is slight. The Red-Yellow Podzolic soils on strongly weathered pre-Wisconsin drift have B2 horizons that have a finer texture than the A2 or C horizons. The parent materials of these soils seem to be strongly weathered because of the high chromas, reddish hues, friable condition of most rock fragments, relatively high kaolinite content, and presence of gibbsite in the clay fraction. Measurements at numerous localities show that the depth of leaching increases with decreasing carbonate content and is not a criterion of the age of the drift. Pebble counts of gravels also show that the depth of leaching of gravel is related to its limestone content. The location of the gravel deposits is probably due primarily to the presence of pebbles of resistant rock rather than to ice wastage involving abundant glacial melt water. The region is in the Susquehanna drainage basin except for its north fringe, which drains to Lake Ontario. Most of the region is a dissected plateau ranging in altitude from 700 to 2,500 feet and underlain by gently folded sedimentary rocks of Paleozoic age. Much of the region slopes moderately or steeply; the most extensive areas of gently sloping land are 011 the uplands. In the northern part are several straight and deep valleys the southern extension of the Finger Lakes basins separated by uplands with several low cuestas that face north. Similarly, some streams such as the Canisteo, Cohocton, and Chemung Rivers, and the part of the Susquehanna River that is in New York, trend at right angles to the Finger Lakes, flowing in valleys that parallel the regional strike of the bedrock. The Olean drift border is marked by a change from drift containing very few rounded or striated rock fragments to a mantle containing only angular rock fragments and traces of red, strongly weathered materials. A reconstruction of the surface of the ice sheet, at its maximum extent shows an inferred slope of its distal margin ranging from 100 to 500 feet per mile

New York, Pennsylvania↗
USGS1952

Late quaternary geology and frost phenomena along Alaska Highway, Northern British Columbia and Southeastern Yukon

Reconnaissance field work along the Alaska Highway in northern British Columbia and southeastern Yukon furnishes preliminary data on the later Quaternary history of the region, and on the processes and results of intensive frost action. Extensive erosion surfaces were developed prior to glaciation, such as the Alberta Plateau of northeastern British Columbia and the Yukon Plateau in southern Yukon . In the region from Dawson Creek to Fort Nelson, British Columbia , the drift is dominantly a slightly weathered bouldery clay till of Wisconsin age, deposited by ice that came from the east. In the northern Rocky Mountains, the last eastward advance of the Wisconsin glaciers to the mountain front preceded the maximum westward advance of the ice sheets. In the foothills belt west of the Highway , the tills of these two advances are separated by lake deposits. Much of the drift is probably pre-Altamont in age and was subjected to vigorous frost action during the Altamont substage. The climate ameliorated perhaps with the advent of the post-glacial optimum and possibly coincident with the development of prairies. A recent change from prairie to forest perhaps indicates a slight cooling in recent time. In the northern Rocky Mountains, four substages of Wisconsin glaciation are recognized tentatively on the basis of morainal deposits and outwash terraces. The upper Liard basin is characterized by extensive pitted outwash plains, probably of late Wisconsin age. From Teslin Lake to Whitehorse, the Highway is bordered by extensive terraces of gravel and sand deposited in ice-marginal streams and lakes. Intensive frost action has modified pre-existing land forms and has produced a wide variety of features, such as talus, blockfields, stone rings, stone stripes, and terraces. Long smooth slopes, chiefly due to mass movements such as solifluction, are characteristic of the landscapes. These slopes and ancient soil structures extend down into forested areas and probably developed prior to the advent of forests, doubtless prior to the post-glacial optimum. Phenomena resulting from intensive frost action at the present time are restricted largely to areas above timber line.

Alaska, Yukon, British Columbia↗