1 / 19

Tasks for today

EMSC2017 - ROCKS AND MINERALS – Semester 1, 2013. Tasks for today. Organisation Assessment Outline of the course Textbooks Class representative Start on ultramafic rocks. EMSC2017 - ROCKS AND MINERALS – Semester 1, 2013 - Organization. Location of lecture and pracs

mia-schultz
Download Presentation

Tasks for today

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. EMSC2017 - ROCKS AND MINERALS – Semester 1, 2013 Tasks for today Organisation Assessment Outline of the course Textbooks Class representative Start on ultramafic rocks

  2. EMSC2017 - ROCKS AND MINERALS – Semester 1, 2013 - Organization Location of lecture and pracs DA Brown Theatre (L2), Building J8, RSES Timetable Lectures on Tuesdays 1200-1300 and Fridays 1000-1100 Prac Sessions on Tuesdays 1400-1700 – CLASHES??? Course Convenor and Lecturer Greg Yaxley E: greg.yaxley@anu.edu.au T: 6125 8334 Rm 119, J1 Lab Demonstrator Brendan Hanger

  3. EMSC2017 - ROCKS AND MINERALS – Semester 1, 2013 - Assessment Indicative assessment • 40% final examination at end of course. • 10% on each of 3 assignments done out of class time. • 10% on each of 3 practical exercises done in Prac Sessions and/or out of class time. • Workload • 65 hours formal contact (26 hours lectures + 39 hours lab classes) • About 55 hours non-contact time for completion of assessable • items, revision etc.

  4. EMSC2017 - ROCKS AND MINERALS – Semester 1, 2013 – Class Rep • Class representatives - 2 volunteers needed! • To liaise between Course Convenor, Lecturers and Associate Director Education (Jörg Hermann) in the event of any problems with the course • Fortnightly meetings with Jörg • Occasional free pizza

  5. EMSC2017 - ROCKS AND MINERALS – Semester 1, 2013 - Books Textbooks • Winter, J.: Introduction to Igneous and Metamorphic Petrology, Prentice Hall • http://www.whitman.edu/geology/winter/ • Gill, R.C.O: Igneous Rocks & Processes, Wiley-Blackwell (≈$80) • http://www.wiley.com/go/gill/igneous • Mineralogy: http://www.webmineral.com/ • PPts and other stuff to be on the WATTLE • Make your own notes!

  6. EMSC2017 - ROCKS AND MINERALS – Semester 1, 2013 – Outline Outline of the course

  7. EMSC2017 - ROCKS AND MINERALS – Semester 1, 2013 – Petrology • Petrology is about the origin of rocks • Focus on igneous and metamorphic rocks i.e. rocks that form at high temperatures and often at high pressures • Continental and oceanic crusts, the Earth’s mantle and other planetary objects (asteroids, the Moon, Mars etc) are all made up of rocks. Petrology is therefore also the science of trying to understand the formation and evolution of these bodies Peridotitexenolith in basalt • In order to achieve this goal, it is necessary to understand how minerals - the basic units that make up rocks - form and behave = Mineralogy • Leads to understanding of the solid earth (and other planetary bodies) as a dynamic and evolving body - tectonics Olivine Clinopyroxene Orthopyroxene

  8. EMSC2017 - ROCKS AND MINERALS – Semester 1, 2013 – Approach Broad approach in learning or researching in Petrology • Observation of rock textures and mineralogy and geochemistry of rocks (including • recognition in hand specimen and petrographic microscope, chemical analysis) • In which settings do particular rocks form on Earth – field observations? • Combine with information from experiments which replicate conditions in the Earth • relevant to formation of rocks or interest – laboratory observations • Leads to understanding of processes of formation and evolution of magmas and • metamorphic rocks (e.g. source, melting, pressure, temperature, fluids, magma, solid state, • eruption, intrusion, crystallisation, etc) • Aim is to understand the large scale dynamic processes operating currently and in the • past on Earth (e.g formation, evolution of structure and chemical composition, • plate tectonics, volcanism, ore deposits, solid state convection, formation of atmosphere….)

  9. EMSC2017 - ROCKS AND MINERALS – Semester 1, 2013 – Lecture 1 Igneous rock classification • Grain size (= size of crystals or mineral • grains comprising the rock • Proportion of light to dark coloured • minerals in hand specimen • Chemical composition (within each • group are further classification • schemes based on mineralogy or • chemical composition) * *

  10. EMSC2017 - ROCKS AND MINERALS – Semester 1, 2012 – Lecture 1 Ultramafic Rocks

  11. EMSC2017 - ROCKS AND MINERALS – Semester 1, 2013 – Lecture 1 Layered structure of the Earth

  12. EMSC2017 - ROCKS AND MINERALS – Semester 1, 2013 – Lecture 1 Peridotite and the Earth’s Upper Mantle • Ultrabasic composition (i.e. SiO2 < 45 wt%). • Ultramafic (i.e. ≥90% dark minerals) • Outcrops rarely in the crust as: • cumulates formed early in crystallisation sequence of • mafic magmas (picrites, basalts, layered mafic intrusions) • ultrabasic magmas erupted onto surface (e.g. komatiites almost restricted to Archean) • xenoliths in some primitive volcanics (alkali basalts, • kimberlites) • tectonically emplaced slices of mantle in crust in • (former) orogenic belts Peridotite is the main rock-type in the Earth’s mantle

  13. EMSC2017 - ROCKS AND MINERALS – Semester 1, 2013 – Lecture 1 Lecture outline • Peridotite mineralogy • Peridotite classification – naming different peridotite types • Minerals in peridotite, olivine, garnet…….

  14. EMSC2017 - ROCKS AND MINERALS – Semester 1, 2013 – Lecture 1 Estimated AVERAGE elemental abundances in Earth’s mantle Most mantle minerals are (Mg,Fe)-rich silicates (based on SiO44- tetrahedra) Most common (Mg,Fe)-rich silicates are OLIVINE and ORTHOPYROXENE = major upper mantle minerals Al, Ca, Na are accommodated in CLINOPYROXENE and/or PLAGIOCLASE, SPINEL or GARNET, depending on composition, pressure and temperature

  15. EMSC2017 - ROCKS AND MINERALS – Semester 1, 2013 – Philosophy Spinel peridotites xenolith from western Victoria, Australia

  16. EMSC2017 - ROCKS AND MINERALS – Semester 1, 2013 – Philosophy Garnet peridotites xenolith from Sarfartoq kimberlite, SW Greenland garnet olivine clinopyroxene orthopyroxene

  17. EMSC2017 - ROCKS AND MINERALS – Semester 1, 2013 – Lecture 1 Beautiful garnet peridotite (and eclogite) from Almklovdalen, Norway

  18. EMSC2017 - ROCKS AND MINERALS – Semester 1, 2013 – Lecture 1 Classification of peridotites – based on modal mineralogy (i.e. volume % of minerals present in the rock) DUNITE 95% OL + 5% OPX = HARZBURGITE 80% OL + 18% OPX + 2% CPX = LHERZOLITE 70% OL + 18% OPX + 12% CPX = WEHRLITE 60% OL + 40% CPX =

  19. EMSC2017 - ROCKS AND MINERALS – Semester 1, 2013 – Lecture 1 Add prefix depending on additional minerals present Spinel lherzolite Garnet harzburgite Spinel wehrlite Plagioclase lherzolite

More Related