100% satisfaction guarantee Immediately available after payment Both online and in PDF No strings attached
logo-home
LEC172 Lecture 12 & Understanding Earth Ch 7 notes £8.46
Add to cart

Lecture notes

LEC172 Lecture 12 & Understanding Earth Ch 7 notes

 8 views  0 purchase

LEC172 Lecture 12 (Metamorphism 2) & Understanding Earth Ch 7 notes

Preview 2 out of 5  pages

  • May 21, 2024
  • 5
  • 2021/2022
  • Lecture notes
  • Jennie gilbert
  • All classes
book image

Book Title:

Author(s):

  • Edition:
  • ISBN:
  • Edition:
All documents for this subject (13)
avatar-seller
ciarangreer
Friday 10th December 2021 LEC 172

Metamorphism – 2

Regional Metamorphism (Cont.):

Metamorphic zones, index minerals and polymorphs:

• First study of metamorphic zones carried out in late 1800s by George Barrow and other British
geologists working in the southern Scottish Highlands

• Regional metamorphism of clay-rich sedimentary rocks

• Zones based on distinctive silicate mineral assemblages

• Mineral assemblages, each recognised by the presence of an index mineral, reflect various degrees of
regional metamorphism

Metamorphic zones are characterised by particular index minerals.

Other index minerals are formed from rocks with
different original compositions.




Barrovian metamorphic zones of the Scottish Highlands…

• When the locations of the first appearances of index minerals are
connected on a map, the result is a line of equal metamorphic
intensity (isograd).

• Pattern of isograds follows faults and folds.




When chemical substances form more than one
kind of crystal structure; different structures are
called polymorphs:

e.g. Al2SiO5 kyanite, andalusite, sillimanite



Metamorphic Facies:

Metamorphic facies is a group of rocks characterised by a specific
mineral assemblage formed under the same broad P-T conditions.

e.g. greenschist facies rocks are dominated by the green mineral
chlorite which forms under low T and P.

Metamorphic facies provide clues to the plate tectonic processes
responsible for metamorphism.

, Contact Metamorphism:

• Occurs when rock is intruded by a body of hot magma

• High T, low P zones of metamorphism develop surrounding the intrusion, i.e. heat from intrusion
metamorphoses the rock immediately surrounding it

• Contact metamorphic rock from originally
clay-rich rock; non-foliated/granoblastic
texture, i.e. any elongate crystals are
oriented randomly = hornfels:

The benefits of buying summaries with Stuvia:

Guaranteed quality through customer reviews

Guaranteed quality through customer reviews

Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.

Quick and easy check-out

Quick and easy check-out

You can quickly pay through credit card for the summaries. There is no membership needed.

Focus on what matters

Focus on what matters

Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!

Frequently asked questions

What do I get when I buy this document?

You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.

Satisfaction guarantee: how does it work?

Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.

Who am I buying these notes from?

Stuvia is a marketplace, so you are not buying this document from us, but from seller ciarangreer. Stuvia facilitates payment to the seller.

Will I be stuck with a subscription?

No, you only buy these notes for £8.46. You're not tied to anything after your purchase.

Can Stuvia be trusted?

4.6 stars on Google & Trustpilot (+1000 reviews)

52510 documents were sold in the last 30 days

Founded in 2010, the go-to place to buy revision notes and other study material for 14 years now

Start selling
£8.46
  • (0)
Add to cart
Added