Springshed Management Training Curriculum Authored by Springs Initiative partners

Transcription

1 Springshed Management Training Curriculum 2016 Authored by Springs Initiative partners

2 Springshed Management Training Curriculum, Draft 2 SESSION TITLE: Rocks Hands-On Practical Session SECTION: Understanding the Resource MODULE: I. Why Springs & Basic Hydrogeology AUTHORS: Dr Jared Buono, Dr Himanshu Kulkarni, Dr Sunesh Sharma, Harshvardhan Dawan CONTRIBUTING ORGANIZATIONS: Acwadam, Arghyam, PSI PURPOSE: A hands-on experience with rocks for ID and properties IMPACT: Participants will be able to distinguish relative grain size, sort rock samples by type and water holding capacity & define primary versus secondary porosity TIME REQUIRED: 90 minutes MATERIALS: This ppt, rock samples from local university, GSI, or museum, magnifying glass, HCl acid (10%) ADDITIONAL RESOURCES:

3 Springshed Management Training Curriculum, Draft 2 Outline: Main rock types Texture and composition for identification Highlights for common rocks Activities: 15 minutes: Presentation of methods for identifying rock types are presented color, hardness, effervescence, grain size/structure, foliation, texture, taste, etc 20 minutes: Rock samples are given out in small groups, participants work to classify the rocks into a set of given categories. 20 minutes: Discussion then follows where we look at projected Meghalaya map of geology and people see what are the main types in their area.

4 Determining rock type Igneous rocks - hard, frozen melts with little layering; minerals mostly black, white, gray, pink. Sedimentary rocks cemented sediments, sandy or silty layers (called strata), often brown or gray Metamorphic rocks minerals often aligned (foliation), varying colours, many times glittery (with mica mineral) Credit: pitt.edu/~cejones/geoimages/ Visible mineral grains, massive texture, no foliation or layers

5 Determining rock type Igneous rocks - hard, frozen melts with little layering; minerals mostly black, white, gray, pink Sedimentary rocks cemented sediments, sandy or silty layers (called strata), often brown or gray Metamorphic rocks minerals often aligned (foliation), varying colours, many times glittery (with mica mineral) Credit: pitt.edu/~cejones/geoimages/

6 Determining rock type Igneous rocks - hard, frozen melts with little layering; minerals mostly black, white, gray, pink Sedimentary rocks cemented sediments, sandy or silty layers (called strata), often brown or gray Metamorphic rocks minerals often aligned (foliation), varying colours, many times glittery (with mica mineral) Credit: pitt.edu/~cejones/geoimages/

7 Texture and other characteristics Grain Size Coarse = visible to the eye Fine = magnification required to ID minerals Effervescence Reacts to acid (HCl, vinegar) Foliation/lineation Minerals aligned by stretch or squeeze Hardness Mohs scale for minerals "hard" scratches glass, steel Igneous rocks (with quartz, feldspar), sometimes metamorphic rocks "soft" does not scratch a steel but scratches fingernails "very soft" rock does not scratch fingernails Credit: USGS

8 Sedimentary specific identification Identification of Sedimentary Rocks Hardness Grain Size Composition Other Rock Type Hard Coarse Clean quartz White to brown Sandstone Soft Fine Clay minerals Splits in layers Shale Soft Fine Carbon Black, burns Coal Soft Fine Calcite fizzes with acid/vinegar Limestone

9 Igneous specific identification Identification of Igneous Rocks Grain Size Usual Colour Other Composition Rock Type fine or mixed Dark Has no quartz Low-silica lava Basalt Coarse Light Wide range of color and grain size Coarse Medium to dark Little or no quartz Coarse Medium to dark No quartz; may haveolivine Feldspar, quartz & minor mica, amphibole or pyroxene Low-calcium plagioclase and dark minerals High-calcium plagioclase and dark minerals Granite Diorite Gabbro

10 Metamorphic specific identification Identification of Metamorphic Rocks Foliation Grain Size Usual Colour Other Rock Type Foliated Coarse Mixed Banded Gneiss Nonfoliated Coarse Light Quartz (no fizzing with acid) Quartzite Foliated Fine Dark Soft, strong cleavage Slate Foliated Coarse Mixed dark and light Wrinkled foliation; often large crystals Schist

11 Specific identification Difference between sandstone and quartz? The former is a clastic sedimentary rock and the latter is the result of metamorphosed sandstone where the clasts and cementing minerals reform under heat and pressure. Quartz has low primary porosity? Can tell the difference by how it breaks, sandstone around clasts/grains but quartzite through grains

12 Specific identification Difference between sandstone and quartz? The former is a clastic sedimentary rock and the latter is the result of metamorphosed sandstone where the clasts and cementing minerals reform under heat and pressure. Quartz has low primary porosity? Can tell the difference by how it breaks, sandstone around clasts/grains but quartzite through grains Credit: pitt.edu/~cejones/geoimages/ Quartzite: Doesn t fizzle with acid

13 Specific identification Difference between sandstone and quartz? The former is a clastic sedimentary rock and the latter is the result of metamorphosed sandstone where the clasts and cementing minerals reform under heat and pressure. Quartz has low primary porosity? Can tell the difference by how it breaks, sandstone around clasts/grains but quartzite through grains Quartzite: Doesn t fizzle with acid Credit: pitt.edu/~cejones/geoimages/

14 Specific identification Credit: pitt.edu/~cejones/geoimages/ Limestone Credit: pitt.edu/~cejones/geoimages/ Coal

15 Specific identification Credit: pitt.edu/~cejones/geoimages/ Shale

16 Additional Resources For pictures of rock examples: How to identify rocks and minerals