... biotite-andalusite-muscovite schist Sillimanite is colorless, has relief much higher than muscovite In medium-grade rocks sillimanite is typically in this fibrous variety Sillimanite fibers can be included in many ... eclogite Omphacite is an Na-Ca-Mg-Al pyroxene, and holds the albite component in this feldspar-free rock Omphacite is pale green and slightly pleochroic Plane polarized light, 100x IG16-36 Omphacite ... Plane polarized light, 100x 4.6.84A Epidotes Epidote in an epidote-amphibolite facies basaltic rock Epidote is the term for the optically negative, high birefringence Al-Fe3+ epidote It is probably...
... important: chemical composition of the original rock (parent rock) – it controls the mineralogy of the metamorphosed rock Temperature And Pressure (1) Rock can be heated by burial or by nearby ... rock is subjected to high pressure or high temperature Deformation type: whether the rock is simply compressed or is twisted and broken during metamorphism Chemical Composition of Original Rock ... Metamorphism Coarse-grained rocks are the products of long sustained metamorphic conditions (possibly over millions of years) at high temperatures and pressures Fine-grained rocks are products of lower...
... formation of the new minerals in a metamorphicrock • What other parameters are important? • What are most important classes of protoliths? Textures of Metamorphic Rocks Foliated Metamorphic Rocks • What ... Gneissic rocks are generally coarse grained ✦ Most commonly used to describe high-grade metamorphic rocks such as gneisses Classification of Metamorphic Rocks Porphyroblastic means that a metamorphic ... Winter (2001) An Introduction to Igneous and Metamorphic Petrology Prentice Hall Foliated Metamorphic Rocks (pelitic protolith) Schist: a metamorphicrock exhibiting a schistosity By this definition...
... Parent Rock morphs into MetamorphicRock Granite (Ign) Gneiss Sandstone (Sed) Quartzite Shale (Sed) Slate Parent Rock morphs into Limestone (Sed) MetamorphicRock Marble METAMORPHICROCK SEDIMENTARY ... SEDIMENTARY ROCK IGNEOUS ROCKMetamorphicrock (marked altered rock) formed when the sedimentary rock surrounding the magma was softened (NOT MELTED) by the heat from the magma The melted rock becomes ... metamorphicrock to show a striped or banded look in some rocks •Examples of foliated metamorphic rocks are gneiss, schist and slate Granite f oliates i nto Gneis s parent rock foliated metamorphic rock...
... completely re-arranged (Yong II Lee) ■ What are metamorphic rocks? ■ Metamorphic rocks form from preexisting rocks (igneous, sedimentary, or other metamorphic rocks) through the action of heat and pressure ... metamorphism from granite or diorite and other rocks ■ Nonfoliated metamorphic rocks ■ Not all metamorphic rocks have a foliated texture Metamorphic rocks composed of only one mineral having equidimensional ... preexisting rocks become unstable and recrystallize in a solid state to become new minerals ■ Study of metamorphic rocks yields valuable information about metamorphic conditions on rock and about...
... that has similar T & P using Uniformitarianism Metamorphic Zones Metamorphic Zones-Map Zones-Map MetamorphicMetamorphic Facies distinctive metamorphicmetamorphic lithologies lithologies that that ... altered altered country country rocks rocks called called forms Aureoles Aureoles Sometimes creates a metamorphicrock called a hornfels -in essence a “cooked” rock Dynamic Metamorphism aka Cataclastic ... and pressures pressures form metamorphic facies facies metamorphic commonly associated associated with with •• commonly shields: areas ofareas crystalline rocks rocks Shields andstable Mountains:...
... Metamorphic Rocks Metamorphic rocks are produced from preexisting igneous, sedimentary, or from other metamorphic rocks Every metamorphicrock has a parent rock – the rock from which ... micarich surfaces that resemble schist Foliated Metamorphic Rocks Gneiss Slate Schist Phyllite Other Metamorphic Textures Not all metamorphic rocks exhibit a foliated texture Those that not are ... minerals, such as garnets Nonfoliated Metamorphic Rocks Marble Quartzite The exterior of the Taj Mahal is constructed mainly of the metamorphicrock marble Metamorphic Environments Hydrothermal...
... Metamorphic rocks When rocks are baked by heat of molten magma or squeezed by the movements of huge tectonic plates or by the pressure of overlying thick succession of rocks They ... segregated in distinct bands in the rocks- known as gneissic banding Classification of Metamorphic rocks based on texture/structures SLATE -strongly cleaved rock -cleavage planes are developed ... to separate from micaceous layers Varieties: Orthogneiss: rocks formed from Igneous rocks paragneiss: rocks formed from Sedimentary rocks -metasedimentary gneisses QUARTIZITE -it comprise...
... transformed into new minerals and rocks In most cases the newmetamorphicrock has the same chemical composition as the parent rock that they formed from Examples of parent rocks and their metamorphic ... into new rocks by heat and pressure below the Earth’s surface Table of Contents The Rock Cycle Table of Contents Metamorphic Rocks Metamorphic rocks are formed when existing parent rocks are ... Nonfoliated Rock Textures (slide 23) Marble (slide 24) Quartzite (slide 25) Metamorphic Rocks in the Landscape (slide 26) Metamorphic Rocks in South Carolina (slide 27) What are Rocks? Most rocks...
... METAMORPHIC FABRIC - The preferred alignment or orientation of minerals within many metamorphic rocks gives those rocks fabric Two principal groups of minerals are involved in this Sheet silicates, ... to the directed stress forces this more ordered alignment METAMORPHIC FABRIC - OPTIONAL We should point not that not all metamorphic rocks have fabric Certain minerals tend to be equidimensional ... between grains Slate – Original Identity Preserved In this low grade metamorphic rock, the original identity of the parent rock can be seen We see graded beds [purple arrows] with light, coarse...
... Rock Cools into Igneous Rock - Shale (Sedimentary Rock) Heat & Pressure Slate (Metamorphic Rock) Slate (Metamorphic Rock) Heat & Pressure Phyllite (Metamorphic Rock) Phyllite (Metamorphic Rock) ... Animation: MetamorphicRock Scheme Where are metamorphic rocks found? At the interface between igneous and sedimentary rocks • Mountainous regions THE ROCK CYCLE How are rocks classified? How are rocks ... Metamorphic Rocks Metamorphic Rocks Formation Conditions that cause rock to undergo metamorphism include: • Heat - Under conditions of high temperature from magma contacting pre-existing rock...
... What is a metamorphic rock? The term "metamorphic" means "to change form." Any rock (igneous, sedimentary, or metamorphic) can become a metamorphicrock If rocks are buried deep ... Foliated Metamorphic Rocks FOLIATED metamorphic rocks are those in which the minerals have been flattened and pushed down into parallel layers The bands in foliated metamorphicrock look ... MetamorphicRock Types There are two types of metamorphic rocks Each is classified according to its composition and texture – Foliated – Nonfoliated To change form Foliated Other rocks are...
... under new P, T conditions, re-crystallize into new minerals • new rocks are metamorphic rocks • metamorphism occurs at depth; cannot see metamorphic rocks unless they are uplifted metamorphic rocks: ... rock: slate foliated metamorphic rock: slate oliated metamorphic rock: phyllite (higher T, P than slate) oliated metamorphic rock: schist (higher T, P than phyllite) new minerals grow garnet (large, ... may take millions of years • longer times allow new minerals to grow larger coarser grained rocks metamorphic rocks: basic classification based on rock texture foliated (layered) type of foliation...
... under new conditions, recrystallize into stable ones • Rocks produced from pre-existing or parent rocks in this way are called metamorphic rocks bread toast Metamorphic Rocks • Metamorphic rocks ... (chemically depleted) Factors Controlling MetamorphicRock Characteristics • Texture and mineral content of metamorphic rocks depend on: – – – – Parent rock composition Temperature and pressure ... millions of years – Longer times allow newly stable minerals to grow larger and increase foliation MetamorphicRock Classification • Classification based on rock texture – Foliated (layered) vs...
... important in the metamorphic process and includes a much larger area of metamorphism—higher temperatures would form a higher grade of metamorphicrock SED-MET ROCKS-AGE • Kinds of metamorphic rocks • ... stocks in country rocks • temperature associated with the intrusive body is the prime metamorphic agent—lower temperatures would form lower grade of metamorphic rocks SED-MET ROCKS-AGE • regional ... metamorphic rocks • all but one rock is comprised of silicate minerals • foliated • minerals are aligned in a pattern Foliated metamorphic rocks Foliated or Lineated Metamorphic Rocks Gneiss Slate Schist...
... THE ROCK CYCLE Metamorphic rocks: typically complex Pressure indicated by fabric (foliation) Heat indicated by growth of new minerals/crystals Metamorphic Rocks Two major types ... temperature & parent rock TEXTURES: INDICATORS OF METAMORPHIC PROCESS Pressurized Heated Foliated rocks: pressurised rocks • Pressure induces re-organisation and growth of new minerals • Large ... Minerals form during metamorphic heating at low pressures Contact metamorphic rocks Spotted hornfels: porphyroblasts Hornfels: uniformly granular Non-foliated metamorphic rocks II: Regional metamorphism...