Igneous Rock Classification & How to Use The QAPF Diagram- Igneous Petrology #1 | GEO GIRL

The first of a series of igneous petrology videos! This video covers igneous rock classification schemes, such as the QAPF diagram and how to classify rocks using these schemes. We also discuss the basics regarding composition and grain size of igneous rocks and how to use these features to identify igneous rocks. I start by going over what igneous petrology is and why we study igneous petrology. Mineralogy is the study of minerals, while petrology is the study of rocks. In igneous petrology we investigate how magmas are produced, how magmas ascend through the mantle and crust, the mineralogical and geochemical evolution of magmas throughout their ascent and eruption, & the emplacement and eruption styles of igneous lavas and magmas. The most basic classification of igenous rocks is based on grain size. Coarse-grained igneous rocks are called plutonic or intrusive, while fine-grained igneous rocks are called volcanic or extrusive. Plutonic and volcanic rocks are further classified by silica content. Felsic rocks are very rich in silica while mafic rocks contain much less silica. An example of a Felsic, plutonic rock is granite. a common example of a mafic, volcanic rock is basalt. The grain size of the rock tell us about whether it cooled at or below earth's surface, while the silica content tells us about its source magma composition. The IUGS created the QAPF diagram for classifying plutonic igneous rocks, and a separate graph for classifying volcanic igneous rocks. Ultramafic rocks are classified by an entire different scheme. I go through all the ingeous rock classification schemes in this video, hope you enjoy! ;) References: Essentials of Igneous Petrology by Ronald and Carol Frost: https://amzn.to/3fJ94XD Earth Materials by Cornelis Klein & Anthony Philpotts: https://amzn.to/3CwyBwY GEO GIRL Website: https://www.geogirlscience.com/ (visit my website to see all my courses, shop merch, learn more about me, and donate to support the channel if you'd like!) 0:00 What Igneous Petrology is & importance 0:47 Importance of Mineralogy Before Petrology 1:22 Classification of igneous rocks 1:43 Classification by grain size (volcanic vs. plutonic) 4:32 Classification by silica (felsic vs. mafic) 5:51 Modal Mineralogy 10:23 IUGS QAPF Diagram 11:26 QAPF Diagram w/rock pictures 17:22 Ultramafic Rock Classification 19:18 IUGS Volcanic Classification 23:35 Textbooks used for this lecture! 24:25 Dog! (not mine, but adorable) Hey there, Earth enthusiast! Check my favorite Earth-friendly products: Bamboo toilet paper: https://shrsl.com/3cvku Bamboo paper towels: https://shrsl.com/3cvkw Compostable tableware: https://shrsl.com/3cvkz Compostable trash bags: https://shrsl.com/3cvl0 Bamboo cutlery + straw! : https://shrsl.com/3cwfl Eco-Friendly Tote (great for grocery shopping!): https://shrsl.com/3cwfp Reusable straws + cleaning brushes (my fav!): https://shrsl.com/3cwft Eco-friendly laundry detergent: https://shrsl.com/3cwgo Directly offset your carbon footprint with Wren: https://shrsl.com/3d0t2 (Just click link, press get started, take the free C footprint quiz, then choose how much you want to reduce your footprint by donating to the C sequestration projects they're funding!) Non-textbook books I recommend: Oxygen by D. Canfield: https://amzn.to/3gffbCL Brief history of Earth by A. Knoll: https://amzn.to/3w3hC1I Life on young planet by A. Knoll: https://amzn.to/2RBMpny Some assembly required by N. Shubin: https://amzn.to/3w1Ezm2 Your inner fish by N. Shubin: https://amzn.to/3cpw3Wb Oxygen by N. Lane: https://amzn.to/3z4FgwZ Alien Oceans by K. Hand: https://amzn.to/3clMx1l Life's Engines: https://amzn.to/3w1Nhke Tools I use as a geologist/teacher/student: Geology field notebook: https://amzn.to/3lb6dJf Geology rock hammer: https://amzn.to/3DZw8MA Geological compass: https://amzn.to/3hfbdLu Geological hand lens: https://amzn.to/3jXysM5 Camera: https://amzn.to/3l6fGRT Carbon-neutral pencil bag: https://shrsl.com/3cvjv Carbon-neutral backpack: https://shrsl.com/3cvkc Disclaimer: Links included in this description might be affiliate links. If you purchase a product or service with the links that I provide I may receive a small commission, but there is no additional charge to you! Thank you for supporting my channel so I can continue to provide you with free content each week! And as always, let me know your topic suggestions in the comments down below!