Lynn S. FichterDepartment of Geology/Environmental ScienceJames Madison UniversityMay, 2008Alluvial FanBraided RiverMeandering RiverDeltaTidal FlatSand DunesTidal ShelfStorm ShelfTransition EnvironmentsCarbonate SystemsBeachBarrier IslandSubmarine CanyonSubmarine FanBasinSHORTSYSTEM LONGSYSTEMSubmarine FanLagoonDistal Shelf SlopeRiseDip FedStrike FedDip FedStrike FedGravel BeachAlluvial Fan/Braided RiverReefFrom sedimentary processes that take place at the Earth’s surface . . . To metamorphic processes that take place below the surface.Minerals and Rocks are stable only under the conditions at which they form.http://www.earthsci.unibe.ch/people/pfiffner/NRP20.htmlDeep Structure of the Swiss Alps:The Mechanisms of Metamorphism• Heat• Pressure• Chemically active fluidsDiagenesis1. Compaction2. Cementation200oCTemperature700-1000PressureConfining (lithostaticand DirectedP 152Calcite cemented sandstone (specifically, a quartz arenite) http://www.gly.uga.edu/railsback/speleoatlas/SAimage0223.htmlphoto to R.Weller/Cochise College. The Mechanisms of Metamorphism• Heat• Pressure• Chemically active fluidsDiagenesis1. Compaction2. Cementation3. Crystal growth200oCTemperature700 - 1000PressureConfining and DirectedClay ChloriteCold/WetProgradeHot/DryRetrogradeMelting1. Parent rock2. Pressure3. FluidsSedimentary layers have justundergone foldingTextural Responses to Changes in Metamorphic Temperature-PressureFoliated TexturesSlaty CleavageNow the slaty cleavage has developed as the clay in the shale has transformed into the mica mineral chloriteP 158Slaty CleavageBeddingSlatycleavageSlaty CleavageDuctile DeformationDuctile DeformationDuctile DeformationDuctile DeformationDuctile DeformationFive Kinds of MetamorphismThe trouble with metamorphism is . . .Any kind of rock, igneous, sedimentary, or metamorphic . . .Can undergo any kind of metamorphism . . .Producing every conceivable combination and permutation.Metamorphic Rocks are Very ComplexFive Kinds of MetamorphismP 155P 165Hydrothermal MetamorphismHot fluids driven from a cooling magma that penetrates into the country rock carrying dissolved minerals that precipitate inthe veins and cracks in the rock.Hot fluids from cooling magmaP 156http://vulcan.wr.usgs.gov/Imgs/Jpg/Baker/baker_fumarole_sampling.jpgHydrothermal MetamorphismAny chemical that cannot crystallize into a rock forming mineral is driven out of the magma as it crystallizes. In this case water (steam) is escaping through a fumarole precipitating the yellow sulfur it is carrying.Hot fluids from cooling magmahttp://maps.unomaha.edu/Maher/geo117/veins.jpegVeins in cores from the basement rocks of the Savannah River Plant in South Carolina. In these two cores you can see two different vein complexes cutting the rock. To the left the white and green material obliquely cutting the core is quartz and epidote the precipitated in the fractures when they opened up. If you look carefully you can see how the quartz is in the interior, and the epidote tends to be on the exterior of the vein suggesting an evoluton of the fluids moving through these cracks. You can also see that multiple cracks exist suggesting this complex opened up and sealed with hydryothermalprecipitates several time. In the core to the right you see pink zeolite crystals in the vein that point inwards to the void which is still left. Note how this vein is discordant to the layering in the enclosing gneiss. Zeolites are hydrothermal index minerals giving some idea to the conditions of formation. They also have useful industrial filtering properties. Hydrothermal MetamorphismHydrothermal minerals precipitated in veins in a rock.Hot fluids from cooling magmaHydrothermal MetamorphismOcean floor fumeroles and gysers (smokers)On the ocean floorVent CommunityP 156157Basalt under the influence of hydrothermal metamorphism turns into two of the softer rocks – soapstone (composed of the mineral talc) and serpentinite (composed on the mineral serpentine).http://www.sandycline.com/sculpture/soapstone.htmlhttp://www.rafa.com/soapstone.htmHydrothermal MetamorphismOn the ocean floorSOAP-STONESERPENTINITESoapstone, which is also known as steatite is a metamorphic rock having a talc base ("metamorphic" means changing from one type of stone to another through time and pressure). It occurs as a secondary mineral formed as a result of the alteration of olivine, pyroxene,and amphibole. The purest talc is used commercially to make talcum powder. Soapstone can be distinguished by its' ease of carving, soapy feel, and vibrant colour, which is obtained by the associated minerals leaching into the talc.Because of its malleability, it has been used as a carving material for centuries. Egyptians carved figures and bowls of soapstone to be put into the tombs of pharaohs. Soapstone seals of Indian origin have been found in Bahrain and Ur. Paleoeskimos were mining the stone to make bowls and lamps on the Baie Verte Peninsula 1600 years ago. Native American Indians throughout North America carved soapstone into ornamental pipes and bowls.http://www.sandycline.com/sculpture/soapstone.htmlhttp://www.sandycline.com/sculpture/soapstone.htmlhttp://www.rafa.com/soapstone.htmhttp://www.kadi.com/bb2004.asphttp://www.kadi.com/bb2004.aspPractical Uses of Soapstone and SerpentiniteBlueschist MetamorphismHigh Pressure – Low Temperaturehttp://catalina-island.visit-los-angeles.com/http://wings-travel.de/avalonopt.jpgSanta Catalina Islandhttp://nmml.afsc.noaa.gov/images/channel.gifChannel Islandshttp://quezst.arc.nasa.gov/neuron/team/journals/oyung/catland.jpTown of AvalonBlueschist MetamorphismWestern side of Santa Catalina island. The sea cliffs are composed of blueschist deposited over an old extinct subduction zonehttp:geology.about.comlibraryblimagePetrologists prefer to talk about the glaucophane-schist facies, because not all blueschist is all that blue. Consider this hand specimen, which displays many different shades. Glaucophane and lawsonite are the major blue species in this rock type, but jadeite, epidote, and quartz are also common. It's hard to tell what's what on this specimen without a microscopeBlueschist MetamorphismEclogite MetamorphismGabbroEclogiteBarrovian MetamorphismP 165Barrovian MetamorphismBarrovian Metamorphismsometimes calledRegional MetamorphismThe kind of metamorphic rock you get depends on the parent rockGranite goes to . . .GneissThe kind of metamorphic rock you get depends on the