Some Slides Lack Permission for Reproduction. These Slides must be deleted before posting as html or pdf! Metamorphic Rocks. GEOL 101 Lecture

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1 Some Slides Lack Permission for Reproduction. These Slides must be deleted before posting as html or pdf! Metamorphic Rocks GEOL 101 Lecture JS Kite WVU What is story behind this rock? Test 1 Results Posted this Morning at Test & : add 9 Test & : add 7 A = >88 B = 75 to 87 C= 62 to 74 D = 50 to 62 F < 50 Class Average = 66.83

2 Diagenesis: All Post-Depositional Physical and Chemical Changes in Sediments and Sedimentary Rocks Up to 150 O C & 1 kb Pressure : Mineralogical & Structural Adjustment to Physical & Chemical Conditions Over 150 o C & 1 Kb Pressure Agents of Pressure Temperature Chemically Active Fluids (Ion-Rich Water or Gasses)

3 Types of Regional Greenschist High Temperature, High Pressure Blueschist Low Temperature, High Pressure Contact High Temperature, Low Pressure Shock Very High Instantaneous Pressure Where Different Types of Occur Contact: High Temp., Low Pressure 1 kb 1 kb Regional (= Green Schist): High Heat + High Pressure Blue-schist Contact Greenschist Where Different Types of Occur (See Fig. 7.15, Box 7.3 in Plummer et al., 10 th ed.)

4 Contact Chilled Zones and Baked Zones Hydrothermal Alteration Source of Ores (Silver, Gold, Lead, Zinc, Tin, etc.) Metamorphic Fabric Granular Foliation Lineated

5 Granular Fabric Quartzite Stress: Force Applied (to a Rock) Strain: Rock s Response to Stress Strain Ellipse

6 Uniform Stress Regional Differential Stress Granite - Igneous Gneiss - Metamorphic Foliated Fabric Fig 7.5 in Plummer et al. 10 th ed., 2005 Foliated Fabric Foliation Foliation Plane Plane

7 Strain: Stretch-Pebble Conglomerate Stress Strain Lineated Fabric Sorry, No Pictures! Original Rx Increasing Partial Sequences of Regional Metamorphic Rocks* Shale Granite Sandstone Limestone Slate Gneiss Quartzite Marble Phyllite Gneiss Quartzite Marble Schist Gneiss Quartzite Marble Gneiss Gneiss Quartzite Marble Migmatite Migmatite Migmatite Migmatite Granite Granite Granite Granite Magma Magma Magma Magma * Leave Room For This Table

8 4 Slate slides not posted pending permission To Explore Slate Quarry Photographs, See Regional of Clay-Rich Sedimentary Rocks Sed Rock Metamorphic Rock Shale Slate 150 o C &/or 1 kb Regional of Clay-Rich Sedimentary Rocks Sed Rock Metamorphic Rock Shale Slate s color varies 150 o C &/or 1 kb

9 Slate Quarry in Action Slate in Storage Jim Covino's production museum.org/images /chips.jpg Regional of Clay-Rich Sedimentary Rocks Sed Rx Increasing Shale Slate Phyllite (note sheen ) Picture for 2001?

10 Regional of Clay-Rich Sedimentary Rocks Sed Rx Increasing Shale Slate Phyllite Schist. Schist in Thin Section Regional of Clay-Rich Sedimentary Rocks Sed Rx Increasing Shale Slate Phyllite Schist Gneiss. Gneiss in thin section

11 Gneiss (sounds nice) GSNL image Gneiss Outcrop Slate Phyllite Schist Gneiss

12 Regional of Clay-Rich Sedimentary Rocks Sed Rx Increasing Partial Shale Slate Phyllite Schist Gneiss Migmatite. Migmatite: Metamorphic Rock that Contains Partially Melted Zones of Igneous Rock GSNL Transitional between image Metamorphic & Igneous Regional of Clay-Rich Sedimentary Rocks Sed Rx Increasing Partial Shale Slate Phyllite Schist Gneiss Migmatite Granite.

13 Granite with Schist Xenolith GSNL image Regional of Clay-Rich Sedimentary Rocks Sed Rx Increasing Partial Shale Slate Phyllite Schist Gneiss Migmatite Granite Magma. Orig. Rx Increasing Partial Sequences of Regional Metamorphic Rocks Shale Granite Slate Gneiss Phyllite Gneiss Schist Gneiss Gneiss Gneiss Migmatite Migmatite Granite Granite Magma Magma.

14 Sequences of Metamorphic Rocks Orig. Rx Increasing Partial Shale Granite Sandstone Slate Gneiss Quartzite Phyllite Gneiss Quartzite Schist Gneiss Quartzite Gneiss Gneiss Quartzite Migmatite Migmatite Migmatite Granite Granite Granite Magma Magma Magma. Quartzite in Thin Section Hexagonal Quartz xls Sequences of Metamorphic Rocks Orig Rx Increasing Partial Shale Granite Sandstone Limestone Slate Gneiss Quartzite Marble Phyllite Gneiss Quartzite Marble Schist Gneiss Quartzite Marble Gneiss Gneiss Quartzite Marble Migmatite Migmatite Migmatite Migmatite Granite Granite Granite Granite Magma Magma Magma Magma.

15 Marble: e.g. Engineering Science Bldg. Foyer Thin Section Review of Coal Genesis Plant Fragments Peat Lignite Bituminous Coal Anthracite Coal Diagenesis 150 o C &/or 1 kb. Metamorphic Rx from Mafic Igneous Rx Greenstone (= Greenschist) Amphibolite Serpentinite Soapstone (Talc + Asbestos).

16 Metamorphic Rx from Mafic Igneous Rx Amphibolite Index Minerals & Metamorphic Grade for Clay-Rich Rocks 150 O C 400 O C 700 O C Clays Chlorite Biotite Garnet Staurolite Kyanite Sillimanite Diagenetic Minerals Low Grade Intermediate Grade High Grade Geologic Map Aureoles

17 Isograds: Lines Separating Metamorphic Zones Name of Rock and Grade Comes From HIGHEST Index Mineral Present e.g. Staurolite Schist May Have Garnet & Biotite in It. Metamorphic Facies (See Box 7.3, p. 171) P T Diagenesis Contact Regional Retrograde Higher Grade Index Minerals may Break Down to Form Lower Grade Index Minerals Requires Chemically Active Fluids & Long Time at New Temperature & Pressure.

18 Porphyroblasts Large xls in met. rx Remember Porphyry (ig. rx)? Porphyroblasts = Last Formed Xls. GSNL image Staurlolite Porphyroblasts GSNL image Augen: Snow-Ball Garnets GSNL image

19 Cataclastic Rocks: Mylonite, Friction Breccia (shown below) GSNL image Metamorphic Rocks, Continued - Contact Geology 101 Section 002 Quiz #3 (Due in class (7 oops) 9 February 2006) 1. What are minimum temperatures and pressures required for metamorphism of rock? 2. Fill out the following table. Original Rock Shale Granite Sandstone Limestone Bituminous Coal Mafic Igneous Rx Metamorphic Rock under Regional * * * * * * * * * Metam. Rock under Contact Hornfels Granite: unless heat = extreme Quartzite Marble Anthracite Hornfels Dolomite (Same as One of the Above)??

20 3. Explain the geological history represented by an outcrop of basalt that is intruded by a dike of rhyolite porphyry. The 5-10 cm of rock that was basalt along the dike is now hornfels. Which rock was there first? Which was there second? What caused the hornfels?