Ore genesis accumulation of hematite gravels called "pisolites" which form channel-iron deposits. These are preferred because they are cheap to mine. Lead-zinc deposits are generally accompanied by silver, hosted within the lead sulfide mineral galena or within the zinc sulfide mineral sphalerite. Lead and zinc deposits are formed by discharge of deep sedimentary brine onto the sea floor (termed "sedimentary exhalative" or SEDEX), or by replacement of limestone, in skarn deposits, some associated with submarine volcanoes (called volcanogenic massive sulfide ore deposits or VMS), or in the aureole of subvolcanic intrusions of granite. The vast majority of SEDEX lead and zinc deposits
Galena, Maryland Galena, Maryland Galena is a town in Kent County, Maryland, United States. The population was 612 at the 2010 census. Galena is located at (39.341680, -75.878444). According to the United States Census Bureau, the town has a total area of , all of it land. Galena was founded in 1763 under the name Down's Cross Roads, after William Downs, a local tavern owner. The name was later changed to Georgetown Cross Roads sometime before 1813, and finally to Galena in 1858. The name comes from a supposed silver mine in the vicinity of the town, which extracted the metal from