Evidence:oGlacial: late Paleozoic glaciers found on five continentsoPaleoclimatic: Wegener predicted rocks defined Pangea climate beltsoFossil: identical fossil found on widely separated land massesoMatching geological unitsoPolar Wandering:When magma cools, its magnetic dipoles are frozenA fixed pole on a wandering continent shows that it is the continent that is moving and not the polar directionNative metals as mineralsNative metals are minerals with no (dominant) anionPure masses of a single metalExamples are: Cu, Au, Ag, PtDistinguishing quartz from clear colourless calcite, gypsum or anhydrite crystalSome identification properties are easily seen: color, crystal shapeSome identification properties require handling or testing: hardness, magnetization, specific gravityHardness: quartz is 4x as hard as calcite, 7 vs. 3.5 on the Mohs scale for hardnessCrystal shape: quartz is a hexagonal prism, calcite is a rhombohedronCleavage: calcite exhibits rhombic cleave, quartz can crack across the crystalChemical composition: calcite (calcium carbonate), quartz (silicon dioxide)Igneous intrusive structures (dykes, sills, plugs, necks, etc.) and Mt. RoyalMagma invades pre-existing wall rock by:
oPercolating upward between grainsoForcing open cracksoTubular, blister-shaped (sill that domes upward), balloon-shaped (blobs of melted rock)Dyke:oCause the rock to expand and inflate and thermally alter the rockoCut across pre-existing layering (bedding or foliation)oSpread rocks sidewaysoSometimes occur in swarmsSills: oCause the rock to expand and inflate and thermally alter the rockoAre injected parallel to pre-existing layeringoSpread rock upwardsoAre usually intruded close to the surfaceMount Royal:oThe gabbroic core of Mt. Royal formed as an intrusion at a depth of about 1.3kmoMagma rose into the sedimentary section which has since been “unroofed”Depositional environments: formation of sedimentary rocksForms at or near Earth’s surface in one of several ways.oCementing loose clasts (fragments) of preexisting rock.oCementing together loose shells and shell fragments.oAccumulation of organic matter from living organisms.oPrecipitation of minerals dissolved in waterSedimentary rocks form layers like the pages of a book.