GEOLOGY

VOL. 32, NO. 1

CONTENTS

Greetings from your State Geologist ........................................................ 1Lake Monongahela: anatomy of an immense Ice Age pond..................... 2Announcement—Survey gets new digs and hosts open house................ 12Earth science teachers’ corner................................................................. 14New releases—Reports on coal-bed methane resources ........................ 16

ON THE COVER

New headquarters for the Bureau of Topographic and Geologic Survey inMiddletown, Pa. (see article on p. 12). The view is of the front of the build-ing, looking across Dogwood Lane. The main entrance is left of the flag-pole, and there is a separate entrance to the library, which is on the rightbeyond the view of the photograph. Photograph by Gary M. Fleeger.

PENNSYLVANIA GEOLOGY

PENNSYLVANIA GEOLOGY is published quarterly by the Bureau of Topographic andGeologic Survey, Pennsylvania Department of Conservation and Natural Resources, 3240Schoolhouse Road, Middletown, PA 17057–3534.Editors: Caron E. O’Neil and Jay B. Parrish.Contributed articles are welcome. Guidelines for manuscript preparation may be obtainedthrough the Internet at URL <www.dcnr.state.pa.us/topogeo/mag-ins.htm> or by contact-ing the editors at the address listed above.Articles may be reprinted from this magazine if credit is given to the Bureau of Topo-graphic and Geologic Survey.

VOL. 32, NO. 1 SPRING 2002

COMMONWEALTH OF PENNSYLVANIAMark Schweiker, Governor

DEPARTMENT OF CONSERVATION AND NATURAL RESOURCESJohn C. Oliver, Secretary

OFFICE OF CONSERVATION AND ENGINEERING SERVICESRichard G. Sprenkle, Deputy Secretary

BUREAU OF TOPOGRAPHIC AND GEOLOGIC SURVEYJay B. Parrish, Director

Visit the Bureau’s web site at www.dcnr.state.pa.us/topogeoDCNR’s web site: www.dcnr.state.pa.us

Pennsylvania home page: www.state.pa.us

DEPARTMENT OF CONSERVATION AND NATURAL RESOURCESBUREAU OF TOPOGRAPHIC AND GEOLOGIC SURVEY

IN COOPERATION WITH THE U.S. GEOLOGICAL SURVEYTOPOGRAPHIC MAPPING

GROUNDWATER-RESOURCE MAPPING

Main Headquarters3240 Schoolhouse Road

Middletown, PA 17057–0053717–702–2017

FAX: 717–702–2065

Pittsburgh Office500 Waterfront Drive

Pittsburgh, PA 15222–4745412–442–4235

FAX: 412–442–4298

BUREAU STAFF AND TELEPHONE NUMBERSDirector and State GeologistJay B. Parrish, P.G. 717–702–2053

Assistant DirectorSamuel W. Berkheiser,

Jr., P.G. 717–702–2055

Administrative ServicesElizabeth C. Lyon 717–702–2063

Library ServicesRichard C. Keen 717–702–2020

Publication ServicesJody R. Zipperer

(General Inquiries) 717–702–2073Christine E. Miles, P.G. 717–702–2044Caron E. O’Neil, P.G. 717–702–2042Anne B. Lutz 717–702–2043

Local Government Outreach ServicesKristen L. Reinertsen

(East) 717–702–2047Jaime Kostelnik (West) 412–442–5828

Web and Computer ServicesKristin J. H. Warner 717–702–2029

Database ServicesCheryl L. Cozart 412–442–4234Karen L. Andrachick (Oil

and Gas GIS Services) 412–442–5248Janice Hayden 412–442–4287Joseph E. Kunz 412–442–4235Lynn J. Levino 412–442–4299

GIS ServicesMichael E. Moore 717–702–2024John H. Barnes, P.G. 717–702–2025Thomas G. Whitfield, P.G. 717–702–2023John G. Kuchinski 717–702–2027James H. Dolimpio 717–702–2026

Water Well ServicesSharon E. Garner 717–702–2074Jody R. Zipperer 717–702–2073

Groundwater ServicesGary M. Fleeger, P.G. 717–702–2045Thomas A. McElroy, P.G. 717–702–2046

Geologic Mapping ServicesJon D. Inners, P.G. 717–702–2034Gale C. Blackmer 717–702–2032Helen L. Delano, P.G. 717–702–2031Clifford H. Dodge, P.G. 717–702–2036William E. Kochanov, P.G. 717–702–2033James R. Shaulis, P.G. 717–702–2037Viktoras W. Skema, P.G. 717–702–2035

Laboratory and Geochemical ServicesRobert C. Smith, II, P.G. 717–702–2021Leslie T. Chubb 717–702–2022

Coal Bed Methane ServicesAntonette K. Markowski,

P.G. 717–702–2038

Coal Quality and Availability ServicesRodger T. Faill, P.G. 717–702–2041Leonard J. Lentz, P.G. 717–702–2041John C. Neubaum 717–702–2039

Oil, Gas, and Subsurface GeologicalServicesJohn A. Harper, P.G. 412–442–4230Christopher D. Laughrey 412–442–4232Joseph R. Tedeski 412–442–4295Kristin M. Carter, P.G. 412–442–4233Lajos J. Balogh 412–442–4231

STATE GEOLOGIST’S EDITORIAL

Greetings From Your State Geologist

When I was about 10 years old, I started receiving Pennsylva-nia Geology, and I would eagerly read it, hoping to glean some newinsight into rocks. Even when I had no idea what an article was about,I felt like I was a part of the greater scientific community, because Iknew that somewhere there were real geologists doing cool geologicthings and reporting back to me.

I never had any intention of being a state geologist. I am, by train-ing, a geophysicist who has a special interest in geobotanical remotesensing. I have worked for Mobil Oil, done research at NASA’s JetPropulsion Lab, and been a college professor, an environmental con-sultant, and most recently, the director of GIS for Lancaster County.As a result, I’m not a great field geologist, but I do bring wide expe-rience in a variety of areas that the Survey is poised to pursue, forexample, GIS, education, remote sensing, geophysics, electronic datacollection and publication, and web mapping. Field mapping will re-main the core of what the Survey does, and we will publish the resultsof our work to make it accessible. My goal is for the Survey to meetyour needs, from geologic consultants to the 10-year-old child yearn-ing for tales of the geologic safari.

On a personal note, Sam Berkheiserdid an excellent job as interim state geolo-gist. He continues to be a great help, and Iam grateful for that help in this period oftransition. And . . . we’ve moved! Our newoffice (see the article on p. 12) is a veryuser-friendly building with plenty of park-ing. Please stop by and visit us at our openhouse on April 10, or anytime.

And, just so you know, as a kid, I neverbothered reading the editorial.

Jay B. ParrishState Geologist

Lake Monongahela: Anatomyof an Immense Ice Age Pond

by John A. HarperBureau of Topographic and Geologic Survey

IN THE BEGINNING . . . Several years ago, an article appeared in thismagazine describing how glaciers reversed the direction of drainagein western Pennsylvania during the Ice Age, forcing the originallynorthwest-flowing streams to flow southwestward around the front ofthe advancing ice sheets (Harper, 1997). Prior to the Ice Age, the Alle-gheny River consisted of three separate and unrelated rivers thatdrained different parts of the state. The “Upper Allegheny” Riverbegan in north-central Pennsylvania and flowed across New Yorkinto Canada. The “Middle Allegheny” River started in Warren Countyand, after wending its way through northern Venango County, flowednorthwest along what is now the valley of French Creek into Canada.The “Lower Allegheny” River originated in Elk, Forest, and JeffersonCounties, followed the course of the present-day Clarion River, andeventually flowed south to join the Monongahela River at what isnow Pittsburgh. The preglacial Ohio River was a mere tributary of theMonongahela River, the dominant river in western Pennsylvania. TheMonongahela flowed north out of West Virginia to Pittsburgh, and thenfollowed the present Ohio and Beaver River channels northwestwardthrough Ohio and into Canada. The preglacial Monongahela River sys-tem drained about three fourths of the area presently drained by thecombined Ohio, Monongahela, and Allegheny Rivers and their tribu-taries in Pennsylvania.

When the Ice Age began in Pennsylvania some 900,000 yearsago (Figure 1), the advancing ice sheets blocked the northwest-flow-ing streams, creating ponds and lakes of varying extents within theexisting drainage areas. As the ponded waters rose, they eventuallycrested and eroded notches in their drainage divides. The escapingwaters scoured the landscape and formed new drainage channelsthat flowed southwestward, closely paralleling the front of the glaciers.The three Allegheny Rivers coalesced to form one, and the mightyMonongahela was forced to flow up the valley of its minor tributary,the Ohio. The Ohio became the major stream of western Pennsylva-nia, flowing south and then west along the boundary of the ice to theMississippi River.

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Ponding occurred each time a glacial advance blocked the rivers,but there is some disagreement as to how many such episodes oc-curred in western Pennsylvania. The ponds that formed during eachsucceeding glacial advance never reached the level of the previous

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Figure 1. Glacial (teal) and interglacial stages of the Pleistocene Epoch corre-lated with reversals of the earth’s magnetic field (normal polarity is shown ingray). Glacial episodes known or inferred to have occurred in Pennsylvania areshown in the darker shade of teal (based on Braun, 1988).

ponding. The notches in the drainage divides, however, continued tobe deepened each time a pond or lake formed and the water foundan outlet, and the river channels became entrenched (Marine, 1997).

LAKE MONONGAHELA. The Monongahela River was the majorstream before and during much of the Ice Age, draining a large areaof Pennsylvania and West Virginia. (It was so different that somegeologists refer to its Ice Age “persona” as the Pittsburgh River todistinguish it from the river we now know.) When the glaciersdammed the river and the waters backed up, the lake that formedwas enormous (Figure 2). I. C. White, the first director of the WestVirginia Geological Survey, named this body of water Lake Monon-gahela (White, 1896). It was not a “lake” in the normal sense of theword (like Lake Erie), but rather a ponded drainage system similarto man-made lakes (like Raystown Lake in central Pennsylvania orDeep Creek Lake in western Maryland), only on a much larger scale.Figure 2 also indicates that the lake extended an unknown distancealong the Ohio and Allegheny drainages beyond what is shown.

Most of what we know or can speculate about Lake Mononga-hela comes from studies of terrace deposits found at high elevationsalong or near the present river channels in West Virginia, Pennsyl-vania, and Ohio. The Monongahela River system became impoundedat least twice, forming a new Lake Monongahela each time, and eachsucceeding lake left evidence at a different elevation (White, 1896;Leverett, 1934).

TERRACE ANYONE? White (1896) and Marine (1997) described aseries of five erosional terraces that occur along or near the valleywalls of the Ohio, Monongahela, and Allegheny Rivers and their majortributaries in Pennsylvania and West Virginia (Table 1) (Lessig, 1961,recognized only four in Ohio). These relatively flat landforms containsoils composed of highly weathered deposits of clay, silt, sand, andgravel distributed at elevations as high as 300 feet or more abovepresent stream levels. Many of these sediments are characteristic oflacustrine, or lake-derived, deposition.

The terrace deposits found at high elevations are scattered through-out southwestern Pennsylvania (for example, Figure 3 shows theirdistribution in Allegheny County). These deposits comprise two, andpossibly more, separate formations of Pleistocene age: the CarmichaelsFormation and glacial outwash deposits.

Campbell (1902) named the Carmichaels Formation for lacus-trine sediments exposed at Carmichaels in Greene County, Pa. Car-michaels Formation terrace deposits occur throughout southwestern

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Pennsylvania and northern West Virginia. These sediments typicallyconsist of reddish-orange to tan clays, silts, and sands that often con-tain cobbles and boulders derived from the local bedrock (Donahueand Kirchner, 1998) (Figure 4A). The clays commonly are of highquality and were the source of raw materials for the early pottery in-dustry in the greater Pittsburgh area. Carmichaels Formation deposits

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Figure 2. Reconstruction ofLake Monongahela based ona water-surface elevation of1,100 feet above currentmean sea level (generalizedfrom Marine, 1997). Totalextent of the lake in the Ohioand Allegheny River valleysis not shown. Modern townsand state boundaries are in-cluded for reference.

occur on the upper twoterrace levels in all theriver valleys, but theycan also be founddraped over lower ter-races in the Mononga-hela Valley and the val-leys of the eastern tribu-taries of the AlleghenyRiver.

The glacial outwashdeposits found on theAllegheny, Ohio, and

Beaver River terraces have no formal names. These deposits typi-cally are rust-colored, deeply weathered gravels composed of small,well-rounded pebbles generally less than 1 inch in diameter (Figure4B). About 10 percent of the pebbles are granites and other crystal-line rocks. Some of these deposits have been thoroughly cementedto form sandstones and conglomerates, whereas others are looseassortments of silt, sand, and gravel. These outwash deposits occuron several terrace levels. Given the time and expertise of an enterpris-ing field geologist or graduate student, it is likely these outwash de-posits could be separated and correlated with the known glaciationsof northwestern Pennsylvania described by White and others (1969).

Terrace deposits can be quite thick. Some preserved outwash de-posits have been measured at more than 90 feet thick, and Leverett(1934) estimated that thicknesses might originally have exceeded120 feet. Carmichaels deposits tend to be much thinner, rarely ex-ceeding 20 feet. Hickock (Hickock and Moyer, 1940), however, indicatedthat these deposits were as much as 80 feet thick in Fayette County.

The five individual terraces do not maintain constant elevationsthroughout western Pennsylvania. For example, the second terracealong the Allegheny River typically is more than 900 feet above sealevel (Marine, 1997), whereas the same terrace level along the Monon-gahela lies about 25 or 30 feet lower (White, 1896). The gradient of theAllegheny, at about 3 feet per mile, also is much steeper than the ap-proximately 0.8-foot-per-mile gradient of the Monongahela. These con-ditions probably resulted from eustatic adjustment of the earth’s crust(crustal rebound) north of Pittsburgh following the retreat of the ap-proximately 2-mile-thick Wisconsinan glacier about 10,000 years ago.

The highest (fifth) terrace occurs more than 300 feet above thecurrent stream levels (Table 1) and can exceed 1,100 feet above sea

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Table 1. Levels of Terraces Above the Three Rivers in the Pittsburgh Area

(from Marine, 1997)

Distance above Distance aboveriver level mean sea level

Terrace (feet)1 (feet)

First 30 740Second 160 900Third 220 960Fourth 260 1,000Fifth 330 1,0401Normal pool level.

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level north of Pittsburgh. Remnants of this terrace actually are higherthan the glacial outwash deposits in the Allegheny River valley. Theyrepresent the channels of streams flowing through western Pennsyl-vania before the Ice Age. The Carmichaels Formation deposits cover-ing those terrace remnants probably represent the highest level reachedby Lake Monongahela during the latest early Pleistocene glaciation(F and/or G in Figure 1) (White, 1896; Leverett, 1934; Marine, 1997).

By the time of the late Illinoian glacial advance (and probablymuch earlier than that), large amounts of glacial outwash were trans-ported down the joined Allegheny Rivers and deposited along thevalley walls. Therefore, most of the fourth, third, and second terracelevels on the Ohio and Allegheny Rivers contain deposits composed

ALLEGHENY COUNTY

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Figure 3. Locations of remnant terrace deposits in Allegheny County (com-piled from Wagner and others, 1975). The modern floodplain (first terrace) isnot included.

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Figure 4. Photographs of Pleistocene terrace deposits in southwestern Penn-sylvania. Rock hammers for scale. A. Sandstone cobbles and boulders in redsand, silt, and clay characterize the Carmichaels Formation at Speers, Wash-ington County. B. Glacial outwash deposits of sand and gravel found along theAllegheny, Ohio, and Beaver River drainages, such as this one in O’Hara Town-ship, Allegheny County (Wagner and others, 1970), have never been named.

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mainly of outwash sand and gravel. Terraces occurring at the sameelevations along the Monongahela River and the eastern tributariesof the Allegheny River tend to have deposits consisting of varyingamounts of sand, silt, and clay, and occasional boulders of local ori-gin (Carmichaels or Carmichaels-type deposits).

The first terrace lies at an elevation of 740 feet above sea levelin downtown Pittsburgh. It climbs in elevation to about 930 feet inthe farthest reaches of the Allegheny River and about 830 feet onthe upper Monongahela River while maintaining a distance aboveriver level of 30 to 40 feet. This is the modern floodplain, which iscomposed primarily of Wisconsinan glacial outwash in the Alleghenyand Ohio Valleys, and sand, silt, and mud containing locally derivedcobbles and boulders in the Monongahela Valley. These depositshave been capped by and mixed with river sediments (alluvium) lessthan 10,000 years old.

The process of creating terraces will continue as long as therivers flow. As the streams continue to cut down their channels andlower their gradients, and/or as the land continues to rise in responseto crustal rebound, remnants of the current floodplain will be pre-served as future terrace remnants.

FROM AGE TO AGE. The ages of the various terrace deposits havebeen debated for more than a century. Early workers such as White(1896) and Leverett (1934) studied the degree of weathering in gran-ite pebbles and the development of soil profiles within the terracedeposits. These methods suggested a pre-Illinoian age for the higherterraces. Modern radiocarbon dating of organic debris in a high terracedeposit near Morgantown, W. Va., suggests a Wisconsinan age ofapproximately 22,000 years before present (Gillespie and Clendening,1968; Behling and Kite, 1988).

The question is further complicated by recent paleomagnetic data.Clay particles formed from weathered rocks containing magneticiron minerals (such as hematite) can be small enough to becomealigned with the earth’s magnetic field. As such, they can indicatethe direction and intensity of the field at the time of deposition orconsolidation of the sediment, thereby retaining the “memory” of themagnetic field. Jacobson and others (1988) and Bonnett and others(1991) obtained reversed magnetic polarity data from third terraceclays in West Virginia and Ohio, indicating a reversal of the earth’smagnetic field during the time of deposition. The most recent paleo-magnetic reversal, the Matuyama, ended 788,000 years ago (Fig-ure 1), suggesting the higher (third through fifth) terrace depositsformed before this time. Marine (1997) also found a reversed mag-

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netic polarity signature from a single sample collected from the fourthterrace in Armstrong County, Pa. However, he concluded that its valuewas suspect because none of the other samples from the same hori-zon, nor from any of the other horizons at various levels and localitiesin the lower Allegheny drainage, exhibited anything but normal polarity.

The data obtained by radiocarbon dating and paleomagneticanalysis are not particularly compelling. Leaching of the sedimentscontaining organic remains might be enough to discount the few ob-served radiocarbon dates. Besides, 22,000 years approaches thelimits of reliability of the radiocarbon dating technology. The paleo-magnetic results are equally suspect. Marine (1997) sampled manydeposits from many terraces in the lower Allegheny drainage, but heobtained a reversed polarity reading from only one sample. This sug-gests that the paleomagnetic reversals documented in West Virginiaand Ohio need to be further verified, and that a larger paleomagneticdatabase needs to be compiled to better constrain the age of thehigh terrace deposits associated with Lake Monongahela.

SO—WHAT’S REALLY GOING ON HERE? Is there a good explana-tion for the various contrary information associated with Lake Mo-nongahela terrace deposits? How many terraces were there, really,and how many episodes of ponding? When did they occur?

First of all, Lake Monongahela did not actually create the ter-races. In most cases, Carmichaels Formation sediments sit directlyon bedrock, indicating that the lake merely deposited sediment onpreexisting terraces. Considering that it would have taken only a fewyears for the ponded lake waters to rise to a high enough level tocrest and erode through the existing drainage divides, Lake Monon-gahela would not have had sufficient time to cut terraces in the localbedrock during any of the ponding episodes.

It was the rivers and their tributaries that created the terraces dur-ing separate depositional and erosional episodes before, during, andafter the Ice Age. The major rivers of western Pennsylvania existedmillions of years before the Ice Age. They were mature streams thatmodified their channels as they meandered within relatively broadvalleys. During the Ice Age, these streams cut their way downward,abandoning meanders and leaving everything from complete loops tofragments of meanders preserved as terrace remnants lining the rivervalleys. Some meanders were far enough inland from the erodingchannels to be preserved as uncharacteristically flat swaths of landwithin western Pennsylvania’s normally hilly topography. They canbe seen at places like Carmichaels in Greene County (MonongahelaRiver cutoff meander), Perryopolis in Fayette County (Youghiogheny

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River cutoff meander), and Perrysville, across from Parker, in Arm-strong County (Allegheny River cutoff meander), to name just a few.

Once Lake Monongahela formed, the ponded waters drownedthe topography, including the abandoned meanders and terraces.The lake did not erode the topography—it simply covered the landwith water and lacustrine sediment. The sediment settled on both topo-graphic highs and lows beneath the surface of the lake. Drowned ter-races and abandoned meander channels, as well as low hills, slopes,and valley bottoms, received this covering of sediment. As such, sedi-ments found on different terraces can actually be the same age.

Marine (1997) found five terrace levels along the rivers, but hehad to conclude that the lake deposits found on them resulted fromonly two episodes of glacial damming. Deposits on the fifth and fourthterrace levels represent damming during a pre-Illinoian glaciation,whereas the third- and second-terrace-level deposits represent dam-ming during Illinoian glaciation. The first terrace (the modern flood-plain) consists simply of Wisconsinan outwash and Holocene alluvialdeposits, which fill river valleys that had been cut to bedrock by theend of Illinoian time. It does not represent a ponding episode.

It will take another Ice Age to recreate Lake Monongahela (thisis not as far-fetched as it sounds). Of course, when that happens, wewill have to call it Lake Ohio. Depending on the southern extent of theglacial ice dam, the lake might extend from as far away as Illinois toWest Virginia and New York. Then we will have a truly Great Lake.

REFERENCES

Behling, R. E., and Kite, J. S., 1988, Additional radiocarbon dates on the late Qua-ternary history of the Monongahela River basin, West Virginia [abs.]: GeologicalSociety of America Abstracts with Programs, v. 20, p. 334.

Bonnett, R. B., Noltimier, H. C., and Sanderson, D. D., 1991, A paleomagnetic studyof the early Pleistocene Minford Silt Member, Teays Formation, West Virginia: Geo-logical Society of America Special Paper 258, p. 9–18.

Braun, D. D., 1988, Glacial geology of the Anthracite and North Branch Susquehannalowland regions, in Inners, J. D., ed., Bedrock and glacial geology of the NorthBranch Susquehanna lowland and the Eastern Middle Anthracite field, northeasternPennsylvania: Annual Field Conference of Pennsylvania Geologists, 53rd, Hazleton,Pa., Guidebook, p. 3–25.

Campbell, M. R., 1902, Masontown-Uniontown folio, Pennsylvania: U.S. GeologicalSurvey Geologic Atlas of the U.S., Folio 82, 21 p.

Donahue, Jack, and Kirchner, Brian, 1998, Pleistocene Lake Monongahela and theCarmichaels Formation in southwest Pennsylvania: Pittsburgh Geological Society,Spring Field Trip Guidebook [not paged].

Gillespie, W. H., and Clendening, J. A., 1968, A flora from proglacial Lake Mononga-hela: Castanea, v. 33, p. 267–300.

Harper, J. A., 1997, Of ice and waters flowing—the formation of Pittsburgh’s threerivers: Pennsylvania Geology, v. 28, no. 3/4, p. 2–8.

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In January 2002, the Bureau of Topo-graphic and Geologic Survey moved out ofits Harrisburg headquarters and into theR. E. Wright building (front cover) in Middle-town, Pa. Our new mailing address and tele-phone numbers are listed on the inside backcover.

The Survey’s new office is located ap-proximately 12 miles southeast of Harris-burg, off the Hummelstown-Middletown exitof Route 283, which is easily accessible fromthe Pennsylvania Turnpike (exit 19) or Inter-

Superstrong Survey Se-nior Geologic Scientist,Bill Kochanov, lifts a stackof boxes filled with heavyrocks!

Hickock, W. O., IV, and Moyer, F. T., 1940, Geology and mineral resources of FayetteCounty, Pennsylvania: Pennsylvania Geological Survey, 4th ser., County Report 26,530 p.

Jacobson, R. B., Elston, D. P., and Heaton, J. W., 1988, Stratigraphy and magneticpolarity of the high terrace remnants in the upper Ohio and Monongahela Riversin West Virginia, Pennsylvania, and Ohio: Quaternary Research, v. 29, p. 216–232.

Lessig, H. D., 1961, Soils of the high terrace remnants in the upper Ohio Valley: OhioJournal of Science, v. 61, p. 286–294.

Leverett, Frank, 1934, Glacial deposits outside the Wisconsin terminal moraine in Penn-sylvania: Pennsylvania Geological Survey, 4th ser., General Geology Report 7, 123 p.

Marine, J. T., 1997, Terrace deposits associated with ancient Lake Monongahela inthe lower Allegheny drainage, western Pennsylvania: University of Pittsburgh, M.S.thesis, 182 p.

Wagner, W. R., Craft, J. L., Heyman, Louis, and Harper, J. A., comps., 1975, GreaterPittsburgh region geologic map and cross sections: Pennsylvania Geological Sur-vey, 4th ser., Map 42, scale 1:250,000, 4 sheets.

Wagner, W. R., Heyman, Louis, Gray, R. E., and others, 1970, Geology of the Pitts-burgh area: Pennsylvania Geological Survey, 4th ser., General Geology Report 59,p. 90.

White, G. W., Totten, S. M., and Gross, D. L., 1969, Pleistocene stratigraphy of north-western Pennsylvania: Pennsylvania Geological Survey, 4th ser., General GeologyReport 55, 88 p.

White, I. C., 1896, Origin of the high terrace deposits of the Monongahela River:American Geologist, v. 18, p. 368–379.

ANNOUNCEMENT

Survey Gets New Digsand Hosts Open House

state 83 (see the back cover formaps and driving instructions).

The Survey offices and libraryare on the upper level of the build-ing, and laboratory and storagefacilities occupy part of the lowerlevel. There are plans to converta large room on the lower level toan activity center where youngvisitors and their older compan-ions can have fun learning aboutPennsylvania’s geology.

The upper level of the build-ing also houses a large confer-ence room (the Learning Center),a computer lab, and a water-well

records area. The conference andcomputer rooms are used formeetings and training classes byBureau and Department person-nel. Anyone wishing to presentgeologic or related research toSurvey staff at our weekly semi-nar series may use the LearningCenter and should contact KristenReinersten at 717–702–2047 tomake arrangements. The water-well records area contains water-well completion reports for ap-proximately the last 15 years.Consultants and other visitorswho wish to view or photocopydrillers’ records on well locations,depths, yields, water-bearingzones, and rock types encoun-tered should contact Jody Zippererat 717–702–2073 to arrange anappointment.

The Survey will be holding anopen house on Wednesday, April10. Project work will be on dis-play, and there will be goodies ofboth edible and printed varieties.Please come and visit us at ourMiddletown office. Open househours will be from 10 a.m. to 3 p.m.

13

At the main entrance of the buildingis a reception area where visitors arewelcomed by Survey staff. Here, JodyZipperer greets John Diehl of the De-partment of Environmental Protection.

The Survey’s library has a large col-lection of topographic maps, aerialphotographs, and geologic texts, maps,and journals. With the exception ofthe topographic maps, most materialsare circulated. Here, patron TomWarman and librarian Rick Keen (back-ground) are hard at work.

14

The Bureau of Topographicand Geologic Survey publishesa series of free booklets designedto educate students and the pub-lic about geology in Pennsylvania.There are now 12 booklets in theEducational Series (ES); each ad-dresses a specific geologic topic(for example, groundwater or fos-sils) and is written at a level easilyread by high-school students. Thebooklets have been a valuable aidto teachers, who can supplementtheir instructions with free hand-outs or use them as a source ofinformation.

At 6 by 9 inches and 14 to 44pages in length, these bookletsare a convenient size and wellillustrated with photographs andsketches. Most of them are dis-played on the Survey’s web siteat www.dcnr.state.pa.us/topogeo/pub/pub.htm. For a complete listof the ES series, see the Survey’sList of Publications, which is alsoavailable on the web site. Thebooklets are free upon requestand may be ordered through theweb site or from the Bureau ofTopographic and Geologic Survey,3240 Schoolhouse Road, Middle-town, PA 17057–3534, telephone717–702–2017.

There are two recent additionsto the Survey’s Educational Se-ries. ES 9, Landslides in Penn-sylvania, written by staff geolo-gist Helen L. Delano, is a new 34-page edition of what was formerlytitled Geologic Hazards in Penn-sylvania. The old edition includedsections on landslides, sinkholes(now in ES 11) and earthquakes(ES 10). Landslides (along withfloods and sinkholes) are amongthe major geologic hazards affect-ing the state. Although total num-bers of occurrences and asso-ciated costs of landslides are un-known, costs probably averageseveral tens of millions of dollarsper year in Pennsylvania. Roads,

EARTH SCIENCE TEACHERS’ CORNER

Survey’s Educational SeriesNow Includes Landslides andNonfuel Mineral Resources

Educational Series 9

LANDSLIDESINPENNSYLVANIA

15

utilities, and buildings can be dam-aged by landslides, but travel de-lays, interruption of businessesand utility services, and other sideeffects also contribute to the costs.Although landslides are a naturalphenomenon, people occupyingand modifying the land surfacetrigger many, if not most, slopefailures in Pennsylvania.

ES 9 includes descriptions ofthe types of landslides commonin Pennsylvania and where theymay occur. It has generalizedmaps of landslide distribution inthe state and references to moredetailed information. Landslideoccurrences can be greatly re-duced by avoiding constructionin some areas and modifying con-struction practices in others. Thefirst step is understanding howand where landslides occur. It ishoped that the revised ES 9 willincrease awareness and under-standing of this hazard.

ES 12, The Nonfuel MineralResources of Pennsylvania, bystaff geologists John H. Barnesand Robert C. Smith, II, is a newbooklet on mineral resources otherthan coal, oil, and natural gas.From the earliest days of WilliamPenn’s “holy experiment,” whenthe colonists were advised to buildhouses of brick to reduce the dan-ger of fire, to the present time,when they constitute a billion-dollar-per-year industry in Penn-sylvania, mineral resources havehelped to shape the developmentof the Commonwealth.

In the first part of this 38-pagebooklet, the authors discuss thenonfuel mineral resources that arepresently mined in Pennsylvaniaand how they are used in manyeveryday activities. The secondpart of the booklet is an explora-tion of the interesting role thatmineral resources played in shap-ing Pennsylvania’s history. Miningin Pennsylvania began at least15,000 years ago with the exca-vation of rocks that native Ameri-cans used to make tools. Later,Pennsylvania became an impor-tant center for the mining of ma-terials that helped to build ournation’s manufacturing industries.It was an important source of chro-mium, iron, nickel, lead, and zinc.Pennsylvania has also been alimited source of gold, silver, cop-per, manganese, salt, feldspar,and other commodities. The book-let ends with a look toward thefuture and a discussion of the roleof mining in modern society.

The Nonfuel

Mineral Resources

of Pennsylvania

Educational Series 12

COMMONWEALTH OF PENNSYLVANIADEPARTMENT OF CONSERVATION AND NATURAL RESOURCES

OFFICE OF CONSERVATION AND ENGINEERING SERVICESBUREAU OF TOPOGRAPHIC AND GEOLOGIC SURVEY

16

NEW RELEASES

Reports on Coal-Bed Methane Resources

Two reports by staff geologistAntonette K. Markowski on coal-bed methane (CBM) resourceshave been published by the Bu-reau of Topographic and GeologicSurvey. Mineral Resource Re-port 95, Reconnaissance of theCoal-Bed Methane Resourcesin Pennsylvania, will interest thenatural gas industry and thosewho wish to make the coal indus-try safer and more lucrative bycapturing and marketing a danger-ous and previouslyoverlooked resource.In this 134-page re-port, the author de-scribes the history,geology, production,and economic poten-tial of CBM in Penn-sylvania.

CBM has heating values com-parable to conventional naturalgas. In 2000, there were approxi-mately 125 wells producing com-mercial methane gas and manyothers that had been drilled forexploration and testing purposesin the Commonwealth. CBM canbe produced from coal seams thatare too thin or deep to permit eco-nomic mining, and its productionhas less environmental impactthan conventional gas drilling.

Mineral Resource Report 95may be purchased from the State

Bookstore, Commonwealth Key-stone Building, 400 North Street,Harrisburg, PA 17120–0053, tele-phone 717–787–5109, for $10.00plus $0.60 sales tax for Pennsyl-vania residents. Payment may bemade with VISA, MasterCard, orcheck or money order payable toCommonwealth of Pennsylvania.If order is to be mailed, include$4.00 postage for one book and$0.50 for each additional book.

The second CBM report is a580-page spread-sheet available as aMicrosoft® Excel 97file on a 3.5-inch disk-ette. Open-File Re-port 00–01, Penn-sylvania Coal-BedMethane Wells, in-cludes data from ex-

ploratory and producing CBM wellsand from serendipitous encoun-ters with the gas in the state from1938 to 2000.

Open-File Report 00–01 maybe purchased for $2.00 plus $0.12state sales tax. Prepayment isrequired; please make check ormoney order payable to Common-wealth of Pennsylvania and sendto Open-File Sales at the Survey’sMiddletown address (see insideback cover). If interested in addi-tional CBM information, contactToni Markowski at 717–702–2038.

Estimates of CBMindicate that theremay be 51 trillioncubic feet of gas-in-place in Penn-sylvania and WestVirginia.

CONTENTS

Greetings from your State Geologist ........................................................ 1Lake Monongahela: anatomy of an immense Ice Age pond..................... 2Announcement—Survey gets new digs and hosts open house................ 12Earth science teachers’ corner................................................................. 14New releases—Reports on coal-bed methane resources ........................ 16

ON THE COVER

New headquarters for the Bureau of Topographic and Geologic Survey inMiddletown, Pa. (see article on p. 12). The view is of the front of the build-ing, looking across Dogwood Lane. The main entrance is left of the flag-pole, and there is a separate entrance to the library, which is on the rightbeyond the view of the photograph. Photograph by Gary M. Fleeger.

PENNSYLVANIA GEOLOGY

PENNSYLVANIA GEOLOGY is published quarterly by the Bureau of Topographic andGeologic Survey, Pennsylvania Department of Conservation and Natural Resources, 3240Schoolhouse Road, Middletown, PA 17057–3534.Editors: Caron E. O’Neil and Jay B. Parrish.Contributed articles are welcome. Guidelines for manuscript preparation may be obtainedthrough the Internet at URL <www.dcnr.state.pa.us/topogeo/mag-ins.htm> or by contact-ing the editors at the address listed above.Articles may be reprinted from this magazine if credit is given to the Bureau of Topo-graphic and Geologic Survey.

VOL. 32, NO. 1 SPRING 2002

COMMONWEALTH OF PENNSYLVANIAMark Schweiker, Governor

DEPARTMENT OF CONSERVATION AND NATURAL RESOURCESJohn C. Oliver, Secretary

OFFICE OF CONSERVATION AND ENGINEERING SERVICESRichard G. Sprenkle, Deputy Secretary

BUREAU OF TOPOGRAPHIC AND GEOLOGIC SURVEYJay B. Parrish, Director

Visit the Bureau’s web site at www.dcnr.state.pa.us/topogeoDCNR’s web site: www.dcnr.state.pa.us

Pennsylvania home page: www.state.pa.us

DEPARTMENT OF CONSERVATION AND NATURAL RESOURCESBUREAU OF TOPOGRAPHIC AND GEOLOGIC SURVEY

IN COOPERATION WITH THE U.S. GEOLOGICAL SURVEYTOPOGRAPHIC MAPPING

GROUNDWATER-RESOURCE MAPPING

Main Headquarters3240 Schoolhouse Road

Middletown, PA 17057–3534717–702–2017

FAX: 717–702–2065

Pittsburgh Office500 Waterfront Drive

Pittsburgh, PA 15222–4745412–442–4235

FAX: 412–442–4298

BUREAU STAFF AND TELEPHONE NUMBERSDirector and State GeologistJay B. Parrish, P.G. 717–702–2053

Assistant DirectorSamuel W. Berkheiser,

Jr., P.G. 717–702–2055

Administrative ServicesElizabeth C. Lyon 717–702–2063

Library ServicesRichard C. Keen 717–702–2020

Publication ServicesJody R. Zipperer

(General Inquiries) 717–702–2073Christine E. Miles, P.G. 717–702–2044Caron E. O’Neil, P.G. 717–702–2042Anne B. Lutz 717–702–2043

Local Government Outreach ServicesKristen L. Reinertsen

(East) 717–702–2047Jaime Kostelnik (West) 412–442–5828

Web and Computer ServicesKristin J. H. Warner 717–702–2029

Database ServicesCheryl L. Cozart 412–442–4234Karen L. Andrachick (Oil

and Gas GIS Services) 412–442–5248Janice Hayden 412–442–4287Joseph E. Kunz 412–442–4235Lynn J. Levino 412–442–4299

GIS ServicesMichael E. Moore 717–702–2024John H. Barnes, P.G. 717–702–2025Thomas G. Whitfield, P.G. 717–702–2023John G. Kuchinski 717–702–2027James H. Dolimpio 717–702–2026

Water Well ServicesSharon E. Garner 717–702–2074Jody R. Zipperer 717–702–2073

Groundwater ServicesGary M. Fleeger, P.G. 717–702–2045Thomas A. McElroy, P.G. 717–702–2046

Geologic Mapping ServicesJon D. Inners, P.G. 717–702–2034Gale C. Blackmer 717–702–2032Helen L. Delano, P.G. 717–702–2031Clifford H. Dodge, P.G. 717–702–2036William E. Kochanov, P.G. 717–702–2033James R. Shaulis, P.G. 717–702–2037Viktoras W. Skema, P.G. 717–702–2035

Laboratory and Geochemical ServicesRobert C. Smith, II, P.G. 717–702–2021Leslie T. Chubb 717–702–2022

Coal Bed Methane ServicesAntonette K. Markowski,

P.G. 717–702–2038

Coal Quality and Availability ServicesRodger T. Faill, P.G. 717–702–2041Leonard J. Lentz, P.G. 717–702–2041John C. Neubaum 717–702–2039

Oil, Gas, and Subsurface GeologicalServicesJohn A. Harper, P.G. 412–442–4230Christopher D. Laughrey 412–442–4232Joseph R. Tedeski 412–442–4295Kristin M. Carter, P.G. 412–442–4233Lajos J. Balogh 412–442–4231

LOCATION MAP FOR BUREAU’S NEW HEADQUARTERS

Bureau of Topographic and Geologic SurveyDepartment of Conservation and Natural Resources3240 Schoolhouse RoadMiddletown, PA 17057–3534

Change Service Requested

PRSRT STDU.S. Postage

PAIDHarrisburg, PAPermit No. 747

An Equal Opportunity/Affirmative Action Employer 2200-BK-DCNR0103

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DirectionsFrom Harrisburg—Follow I-83 North to I-283 South. Takethe Lancaster exit onto Route 283 East.From the PA Turnpike—Take exit 19, Harrisburg East,and then take the first exit onto Route 283 East.From Route 283 East—Take the Hummelstown-Middle-town exit. At the end of the ramp, turn left onto VineStreet. Stay in the left-hand lane and turn left at the firstintersection onto Schoolhouse Road. Make the next leftonto Dogwood Lane. At the top of the hill, take the firstright into the parking lot.

If you would like to receive up-to-date Bureau announcements,please send your e-mail address to pageology@state.pa.us.