GEOLOGY OF THE LUZERNE QUADRANGLE 6l 



The most recent movement of the land has been a differential 

 uplift with greater elevation toward the north. At the latitude of 

 the Luzerne quadrangle this postglacial uplift has amounted to 

 several hundred feet with a rate of increase toward the north of 

 several feet a mile. The differential character of this uplift is 

 clearly shown by the present positions of the delta deposits of 

 extinct glacial Lake Warrensburg in the Hudson valley. 



MINES AND QUARRIES 



Magnetic Iron Ore 



Within the quadrangle several attempts have been made to oper- 

 ate magnetic iron ore mines. Most important are several open cuts 

 on the southeastern slope of Mount Anthony, i% miles due south 

 "> of Luzerne (between 900 and iioo feet in altitude). One open 

 cut is about 40 feet deep and 100 feet long, and another is nearly ' 

 as large. The magnetite is always in moderately coarse-grained 

 gray pegmatite in masses up to an inch or more across. The work- 

 ings follow pegmatite dikes. The garnetiferous wall rock is pre- 

 sumably Grenville gneiss more or less intimately cut and injected 

 with granite and pegmatite. Some amphibolite (metagabbro?) 

 seems also to be associated with the wall rock, and nearby there is 

 grano-syenite containing pegmatite and bands of amphibolite. It 

 was stated by an old resident of Luzerne that this mine was oper- 

 ated about 30 or 40 years ago, and that some ore was shipped. 



At the southwestern base of Mount Anthony (see map) a small 

 iron mine was operated about 25 years ago when some tons of 

 magnetitic iron ore were taken out. The ore is in fairly coarse- 

 grained pegmatite, and the country rock seems to be amphibolite 

 (metagabbro?) injected with granite. 



A small attempt to mine iron ore was made 2^4 miles southwest 

 of Thurman station, one-sixth of a mile west of the road (altitude, 

 about 900 feet). The magnetite occurs in scattering masses in a 

 pegmatite dike several feet wide cutting granite at the western 

 border of the little body of gabbro shown on the map. 



Not only at the localities above mentioned, but also at various 

 other places within the quadrangle, magnetite, in amounts large 

 enough to be at all classed as ore, was always observed to be 

 directly associated with granite, pegmatite and gabbro or am- 

 phibolite. Thus, many small pegmatite dikes cutting the meta- 

 gabbro-granite mixed rocks on the hill just south of Mount 



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