Lecture 3a Igneous Rocks

Lecture 3a Igneous Rocks - Extrusive Igneous Rocks Igneous...

Info icon This preview shows pages 1–8. Sign up to view the full content.

View Full Document Right Arrow Icon
Igneous Rocks: Igneous : Latin ignis = fire; form from cooling of melted rock. Extrusive (volcanic): Produced when magma gets to the surface. At that point called lava, crystallizes rapidly into volcanic rocks. Intrusive (plutonic) : produced when magma cools to solid before it has reached the surface. magma crystallizes slowly at depth; we can t see this happening. have to wait for uplift and erosion to expose deep rocks. Intrusive Extrusive
Image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Plate Tectonic Settings Where Igneous Rocks Form
Image of page 2
Melted rock =magma = melt + crystals + gasses. Consists of: – Liquid made of elements found in silicate minerals. – Gasses: H 2 O CO 2 S – Crystals: either old that didn t melt; Or new that grew from melt.
Image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Temperature Control of Rock Melting At constant pressure: Rocks are solid at low temperatures Rocks are liquid at very high temperatures As temperature increases, rocks do not melt uniformly That is, some minerals melt at lower temperatures than others This is called partial melting Pressure Temperature 0 % melt 10 % melt 50 % melt 100 % melt Liquid Solid
Image of page 4
Pressure Control of Rock Melting As pressure decreases, rocks can begin to melt without a change in temperature This process is called decompression melting Decompression melting is responsible for mid- ocean ridge magmatism Pressure Temperature 0 % melt 10 % melt 50 % melt 100 % melt Liquid Solid
Image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Fluid Control of Rock Melting At constant pressure and temperature, addition of fluids, such as water, lowers the melting temperature Therefore, if fluid is added, rocks can begin to melt without a change in temperature or pressure This process is called fluid- induced melting Fluid-induced melting is responsible for subduction-zone magmatism 0 % melt 10 % melt 50 % melt 100 % melt Pressure Temperature Liquid Solid Little fluid
Image of page 6
Fluid Control of Rock Melting At constant pressure and temperature, addition of fluids, such as water, lowers the melting temperature Therefore, if fluid is added, rocks can begin to melt without a change in temperature or pressure
Image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 8
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern