Surficial Geology of the Kezar Falls 7.5' Quadrangle, Maine
Total Page:16
File Type:pdf, Size:1020Kb
DE PART MENT OF CON SER VA TION Maine Geo logi cal Sur vey Rob ert G. Marv in ney, State Ge olo gist OPEN- FILE NO. 97-67 Ti tle: Sur fic ial Ge ology of the Kezar Falls 7.5-minute Quadran gle, Ox ford and York Coun ties, Maine Author: P. Thompson Davis and Wil liam R. Holland Date: 1997 Fi nan cial Sup port: Funding for the prepara tion of this report was provided in part by the U.S. Geo logi cal Sur vey STATE MAP Pro gram, Co op era tive Agree ment No. 1434- 92- A- 1071. As so ci ated Maps Surfic ial geol ogy of the Kezar Falls quad rangle, Open- File 97-52 Surfic ial materials of the Kezar Falls quad rangle, Open- File 98-230 Con tents: 14 p. re port Maine Geo logi cal Sur vey Open- File 97- 67 Surficial Geology of the Kezar Falls 7.5-minute Quadrangle, Oxford and York Counties, Maine P. Thompson Davis De part ment of Natu ral Sci ences Bent ley Col lege Waltham, Mas sa chu setts 02154- 4705 Wil liam R. Hol land1 INTRODUC TION This re port de scribes the sur fic ial and Qua ter nary ge ol ogy shows spe cific site data used for com pil ing the surfic ial geologi c of the Kezar Falls 7.5- minute quadran gle in southwest ern map. These data in clude ob serva ti ons from sand and gravel pits, Maine. Sur fic ial ma te ri als in clude un con soli dated sedi ments of shovel and auger holes, construc tion sites, and natural expo sures glacia l and non- glacial origin that overli e bedrock over much of along stream banks. Sand and gravel aq uifer stud ies by the the quad rangle. Most of these sedim ents were de posit ed during Maine Geologi cal Survey and the U.S. Geologi cal Survey pro - and after the most re cent episode of glacia tion, which spans vided ad diti onal in form ati on about the map area, in cluding seis- about the last 25,000 years in Maine. Sur fic ial ma teri als are im- mic logs and depth-to- bedrock data (Wil liams and oth ers, 1987). portant for many aspect s of eco nomic and envi ron m ental geol - Sup ple men tal depth- to- bedrock data were ob tained from MGS ogy, includ ing sand and gravel extra cti on for the aggre gate well inven to rie s. Field work for this project consis ted of driving in dus try, de vel op ment and pro tec tion of ground- water sup plies, the road net work, in clud ing nu mer ous un im proved log ging disposal of wastes in landfil ls, and agri cul ture . roads not shown on the topographi c map base, and hik ing across Detai led mapping of the surfic ial geol ogy of the Kezar many off-road areas to exam ine bed rock out crops, borrow pits, Falls quadran gle was be gun by Wil liam R. Hol land in 1983 for and natu ral expo sures of surfic ial mate ri als . The authors used a the state/fed eral Sig nifi cant Sand and Gravel Aq ui fer Pro ject shovel and hand auger to identi fy near-surfac e mate ri als in some and the Maine Geologi cal Survey' s (MGS) geologi c mapping places where ex po sures were lack ing. The sur fic ial ma te ri als program . The aq uifer map was include d in a report by Wil liams map pri maril y shows specif ic places where infor m ati on was ob- and others (1987), but the geologi c map was not com pleted be- tained from beneat h the ground surface . In many places the cause of Hol land's unti mely death in 1989. P. Thomp son Davis authors were able to disti nguish map units, such as esker system s com pleted the field mapping of the Kezar Falls quadran gle in and lakebed surface s, on the basis of topog raphy . In some rem ote 1993-1995, which is sum mariz ed in this re port for the STATE- areas , such as the southeas tern porti on of the quadran gle, aerial MAP pro gram, supporte d by the MGS and the U.S. Geologi cal pho tographs were used to dif feren ti ate map units, such as swamp Sur vey. de pos its. Two maps accom pany this report. The sur fic ial geo logic map (Davis and Hol land, 1997c) shows the distri bu tion of the sedi men tary units, whose age, com po si tion, stra tigraphic re la- Geo graphic Set ting tion ships, and ori gin are dis cussed in this re port. This map also include s infor m ati on relat ed to the geologi c his tory of the quad- The Kezar Falls 7.5-m inute quadran gle is locat ed in the ran gle, such as gla cial ice- flow di rec tional in di ca tors. In con - White Mountai n foothil ls, within Oxford and York Counti es, in juncti on with similar mapping in adja cent quadran gles , this map southwest ern Maine. The map area extends in lati tude from provides a basis for discus sion of the gla cial and postgla cia l his- 43o45'00" to 43o52'30" N, and in longi tude from 70o52'30" to tory of the region. The sur fic ial ma te ri als map (Davis, 1998) 71o00'00" W. The east-cent ral porti on of the quadran gle in cludes 1De ceased the town of Kezar Falls, which is the princi pal popula ti on center and locat ed along the Ossipe e River. 1 P. T. Davis The most signifi cant physiographi c fea tures in the Kezar The authors are grateful to num erous land own ers and pit Falls quad rangle in clude a number of hills with steep south- op erators who granted acces s to their proper ti es and often pro - facing cliffs in the north; a chain of four large ponds in the north- vided us with useful in form ati on about the local sand and gravel east (Clemon s, Lit tle Clemon s, Trafton, and Stanley Ponds); two depos it s. In parti cular , Dwight Mills provided acces s in North large lakes in the northwest (Bickford and Colcord Ponds); and Parson fie ld to excel lent expo sures of ribbed mo raines and a the Os sipee River, which flows west to east across the middle strati fied sand and gravel deposit on Mudgett Road. Thanks are part of the quadran gle. The high est point in the quadran gle is also due Woody Thomp son and Tom Weddle for review ing this 1340 ft (408 m) along the east ridge of an unnam ed peak locat ed re port. in Freedom , New Hamp shire, west of Bickford Pond. At 1187 ft (362 m), Bald Ledge, in the northwest corner of the quadran gle, DESCRIPTION OF GEOLOGIC MAP UNITS is the highest peak. The low est point is be low 340 ft (104 m) on the Ossipe e River (on the eastern boundary of the quadran gle) , The sur fic ial de pos its of the Brown field quad ran gle have yielding a reli ef of 1000 ft (305 m). With the ex cepti on of the Os- been rep resent ed on geologi c maps as a se ries of units on the ba- sipee and South River valley s, the ter rain over most of the quad- sis of their age and ori gin. These map units are desig nate d by let- ran gle is hilly, with many of the larger hills ex hib it ing steep ter sym bols, such as “Pt.” The first letter in di cates the age of the bedrock cliffs on their south slopes. unit: Bed rock Ge ol ogy “P” = Pleisto cene (Ice Age) Most of the Kezar Falls quad rangle is under lai n by me- “H” = Holo cene (postgla cia l time, i.e. formed during the tasedim entar y rocks assigne d to the lower mem ber of the last 10,000 years) Rindgem ere For mati on, which probably is Silu ria n in age (Hussey, 1985). This mem ber gener all y con sists of high-grade “Q” = Qua ter nary (en compasses both the Pleis to cene and schists and migm ati tes in the Kezar Falls 7.5-m inute quadran gle Holocene epochs) (Gil man, 1977). Out crops of the Rindgem ere Form ati on are moder ate ly to highly weath ered. The northeas tern part of the The Qua ter nary age is assigne d to units that overlap the quad ran gle is un der lain by Devonian- age gra no dio rite; the Pleistocene-Holoc ene boundary , or whose ages are uncer tai n. northwest ern part is under lai n by the Devonian-age Effingham The other letter s in the map sym bol in dicat e the origin and/or as- pluton and the Trias sic - to Jurassic-age Con way granit e; and the signed name of the unit, e.g. “t” for gla cial till or “Qlt1” for de- southwest ern part of the quadran gle is under lai n by the Effing- pos its re lated to the higher level of gla cial Lake Ten mile.