Lecture-12-F10 - EAS 111 General Announcements 10/13/10 •...

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Unformatted text preview: EAS 111 General Announcements 10/13/10 • Schedule Reminder This week – NO LABS – Weds 10/13 Metamorphism & Sedimentary Processes and Rocks, Part 1 Next week (10/18 & 10/20) – Mon 10/18 Sedimentary Processes and Rocks, Part 2 – Weds 10/20 Geologic Time, Part 1 – Bring your text for lab next week! The week after that (10/25 & 10/27) and beyond – Mon 10/25 – Geologic Time, Part 2 – Weds 10/27 – Review for Lab Exam 2 and Lecture Exam 2 – Monday 11/1 = EXAM 2 – Lab Exams run from Tues 11/2 through Friday 11/5 Earth and Atmospheric Sciences 111 Fall 2010 Metamorphism Lite Sedimentary Processes and Rocks Part I -Metamorphism Basics -Weathering and Erosion -Sedimentary Environments -Sedimentary Rocks Lecture 12 Processes that Cause Metamorphism Burial Subduction Heating Hot fluids Change in stress Shearing 08.09.a Causes of Causes Metamorphism Metamorphism Response of Rock Pressure Tectonic Tectonic stress stress Deform Cut by Cut Veins Veins Fluids Grow larger Grow minerals minerals Grow new Grow minerals minerals 08.08.a Temperature Physical Processes During Metamorphism Deformation Deformation of objects of Rotation 08.08.b Folding Shearing Fracturing Foliation 08.06.b Schistosity Gneissic foliation Flattened pebbles Foliation from shearing Consider the structural behavior of rocks at shallow Consider versus deep conditions versus 08.01.c At shallow At depths, most rocks break rocks Temperature and Temperature pressure increase with depth with Rocks flow Rocks in deep conditions conditions Consider how minerals respond at shallow versus Consider deep conditions deep Shallow: Shallow: minerals may be unaffected unaffected Deep: Deep: minerals may recrystallize recrystallize 08.01.c CPS: What is true about metamorphic rocks? CPS: A. Metamorphic rocks have always been completely melted as they change A. Metamorphic rocks were altered in the solid state A. Metamorphic rocks were always sedimentary rocks just before they were metamorphosed. A. Are only changed in the very deep crust Sedimentary Rocks Sedimentary - Record of surface processes - Formed from debris from weathering of other rocks - Volumetrically small part of crust, but covers ~70% of continental crust (i.e. exposed land) EAS 111: Earth Science News Titanoboa cerrejonensis, February 4, 2009 Nature •60-million-years old •1,140 kilograms (2,500 pounds) •13 meters (42.7 feet) nose to tail tip • "At its greatest width, the snake would have come up to about your hips," said geologist David Polly of Indiana University • Titanoboa would have required an average annual temperature of 30 to 34 degrees Celsius (86 to 93 Fahrenheit) to survive. Resources in Sedimentary Rocks Groundwater Petroleum Coal Cement from Cement limestone limestone Salt Uranium 07.14.a Making Sediment: Physical Weathering Fracturing Frost and mineral Frost wedging wedging Roots and Roots other biologic activity activity 07.03.a1 Making Sediment: Chemical Weathering Dissolution Hydrolysis Oxidation Biological Biological reactions reactions 07.03.a1 05.10.c1 CPS: Which of these is the LEAST prone to chemical weathering? prone weathering? A B C D Clast Sizes Sand: Coarse, medium, fine Boulders, cobbles, Boulders, pebbles pebbles Clay and silt 07.04.a Observe the range of clast Observe size (sorting) in each photograph photograph Moderately sorted Poorly sorted 07.04.a Well sorted Observe the shape of Observe these clasts these Partially rounded Angular 07.04.a Rounded Controls on Size, Shape, and Sorting Farther from source means rounder and smaller Steepness of Steepness slope slope Strength of current Agent of transport 07.04.b CPS: I have found a sediment sample that has poor sorting & good rounding. What can I say about the agent of transport and physical setting? transport A. B. Very far from the source, transported by wind Very close to the source, transported by gravity Very only only Somewhat close to the source, transported by Somewhat water water Very far from the source, transported by water C. D. Clastic Sediment Becomes Rock= Lithification Compaction of Compaction sand grains sand Compaction of Compaction clay particles clay Cementation 07.05.a Common Clastic Sedimentary Rocks Conglomerate Breccia 07.05.b Sandstone Shale Indicators of Environment Color of rocks Size, shape, sorting Thickness of bedding Type of bedding Mudcracks Fossils 07.13.a Observe these environments and their sediment sediment Glacier Glacier Mountains Steep stream Steep or river or 07.01.a Sand dunes Observe these environments Observe and their sediment sediment Gentle, Gentle, meandering river river Delta Delta 07.01.a Wetlands Lake Observe these environments Tidal flat Delta 07.02.a Deep Deep ocean ocean Carbonate Rocks and Their Environments Limestone Limestone w/ fossils Dolostone Carbonate Rocks in Landscape Limestone Limestone Soluble limestone Dissolved Dissolved 07.11.d Observe these environments Observe and their sediment sediment Coastal Coastal dunes dunes Beach 07.02.a Lagoon Reef EAS 111: Assignments for 10/18/10 • Reading in Exploring Geology • Sedimentary geology readings assigned for today • AND, to catch up with today’s lecture: Chapter 8 – Deformation and Metamorphism 8.8 – How Rocks Change during metamorphism 8.6, 8.7 – Metamorphic Fabrics and Rocks 8.9 – Why does metamorphism happen? Lightly: 8.11, 8.12, 8.13 – Metamorphism and Plate Tectonic Margins – 8.6 and 8.7 will help in lab for reference ...
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This note was uploaded on 01/12/2011 for the course EAS 111 taught by Professor Dr.ericriggs during the Spring '10 term at Purdue University.

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