Geology 306: Earth Science Laboratory: Rock Identification Supplement Hydrological Cycle and the Rock Cycle

Total Page:16

File Type:pdf, Size:1020Kb

Geology 306: Earth Science Laboratory: Rock Identification Supplement Hydrological Cycle and the Rock Cycle Geology 306: Earth Science Laboratory: Rock Identification Supplement Hydrological cycle and the Rock Cycle The Rock Cycle 1. The rock cycle and hydrological cyle both involve the recycling of materials, such as water between the surface and the atmosphere or the recycling of the various types of rocks that make up the surface of the Earth. 2. All rocks are classified based upon their mineral content (mineral composition) and visual texture. a. Texture: The size, shape and arrangement of mineral (crystal) grains or fragments of material. 3. Types of Rocks: a. Igneous Rocks: are associated with the crystallization and/or solidification of Magma. i. Intrusive igneous rocks cool slowly underground and form larger crystals, such as granite. ii. Extrusive igneous rocks cool rapidly on or near the surface and form much smaller crystals (such as basalt) and in some cases no crystals at all, such as obsidian which is an amorphous or glassy material. Extrusive igneous activity can also produce violent volcanic eruptions which can produce more fragmental material. b. Sedimentary Rocks: are associated with the accumulation of weathering by-products produced by weathering and erosion on the surface, such as sandstone. c. Metamorphic Rocks: are associated with the alteration and deformation of pre-existing rocks known as parent rocks. These parent rocks are deformed by: Heat, Pressure, and Chemically- active fluids to produce new metamorphic rocks, such as Marble or Gneiss. 4. Igneous Rocks: are classified based on their overall mineral content and visual texture. a. Mineral composition: is based upon the abundance of Ferromagnesian (minerals rich in iron and/or magnesium) and Non- ferromagnesian minerals (minerals that lack iron and/or magnesium), which is in turn influenced by Bowen’s Reaction Series. Bowens Reaction Series i. Bowen’s Reaction Series: describes the sequence of mineral formation in a cooling magma. • Discontinuous Series or Branch: consists of the ferromagnesian minerals: Olivine, Pyroxene, Amphibole, and Biotite, which are all dark, ferromagnesian minerals. • Continuous Series or Branch: consists of the non- ferromagnesian minerals, Calcium-rich Plagioclase feldspar and Sodium-rich Plagioclase feldspar, which are lighter colored than the discontinuous branch. • Muscovite, Potassium Feldspar (Orthoclase), and Quartz: are all light-colored non-ferromagnesian minerals. ii. Mineral content: will reflect the minerals that are present at the temperature in which the rock solidified. For example, rocks that solidify at higher temperatures may contain more olivine, pyroxene, and calcium-rich plagioclase feldspar. Rocks that solidify at very low temperatures will contain more quartz and potassium feldspar. b. Compositional classes: can be determined by the amount of light (non-ferromagnesian minerals) and dark (ferromagnesian minerals). i. Ultramafic: the composition of the mantle (peridotite) and rarely found on the surface. Contains mostly olivine, pyroxene, and a small amount of calcium-rich plagioclase feldspar. ii. Mafic: Contains mostly dark, ferromagnesian minerals such as: olivine, pyroxene, as well as, calcium-rich plagioclase feldspar, and small amounts of amphibole minerals. These rocks tend to be dark and denser, such as the rock, Basalt. iii. Intermediate: Contains mostly amphibole, biotite mica, sodium-rich plagioclase feldspar, and small amounts of pyroxene and calcium-rich plagioclase feldspar. Typically seen as half ferromagnesian and half non-ferromagnesian minerals, but can have a range of compositions. Intermediate colors, such as the rock diorite and/or andesite. iv. Felsic: Contains mostly non-ferromagnesian minerals, such as: quartz, potassium feldspar, and muscovite mica, with small amounts of biotite, amphibole, and sodium-rich plagioclase feldspar. Typically light in color, such as granite Mineral content of felsic, Intermediate, mafic, and ultra-mafic rock compositions: Igneous Rock Textural Terms INTRUSIVE TEXTURES associated with Plutonic environments and slow cooling: Phaneritic: Uniform, slow-cooling, and coarse-grained, easily seen, e.g. granite (typical intrusive texture) Pegmatitic: very coarse-grained, larger than your thumb (1-inch) Often forms due to slow cooling of a fluid-rich magma and can produce semi-precious gemstones such as aquamarine, tourmaline, etc. (if this texture is present, the term Pegmatitic is included in the rock name) (E.g. Pegmatitic granite or granite pegmatite) Porphyritic: Two or more grain sizes are present due to multiple stages or rates of cooling. Phenocrysts (larger crystals) are set in a finer grained matrix due to two or more stages of cooling underground. (If this texture is present, the term Porphyritic is included in the rock name, e.g. porphyritic granite.) EXTRUSIVE TEXTURES associated with volcanic environments and rapid cooling or violent volcanic eruptions: Aphanitic: Uniform, rapid cooling, fine-grained, not visible except under a microscope, e.g. basalt (typical extrusive texture). Porphyritic: phenocrysts in a finer grained matrix due to two or more stages of cooling with the last stage of cooling occurring on the surface. (If this texture is present, the term Porphyritic is included in the rock name, e.g. porphyritic basalt.) Glassy: similar to glass, due to very rapid cooling and the lack of crystal formation, e.g. obsidian. Vesicular or Cellular: many visible vesicles formed as magma cooled around gas bubbles that were escaping, thus preserving the spherical shape of the gas bubbles. (When large very large vesicles are present the term vesicular is added to the rock name, e.g. vesicular basalt, otherwise specific rock names such as scoria may be used.) Amygdaloidal: Vesicles are filled in with secondary minerals, e.g. amygdaloidal basalt. (If this texture is present, the term Amygdaloidal is included in the rock name, e.g. Amygdaloidal Basalt.) Frothy: glassy & vesicular, many small vesicles, foamy-looking, e.g. pumice. Fragmental/Pyroclastic: particles, ash, fragments (which are typically angular) of rock, etc. fused together, e.g. welded tuff, volcanic breccia. Some Igneous Rock Classifications Emplacement of Plutonic Structures / Formation of Plutons Sedimentary Rocks The following diagram depicts the chemical equations important to chemical weathering and the formation of chemical cements. 1. Sedimentary rocks: form through the accumulation of weathering by- products, of which there are many types. These by-products will produce different types of sediments based upon their origin. Diagenesis describes the sequence of events or processes that transform a sediment into a sedimentary rock and often includes: deposition, burial, and Lithification (compaction and cementation) of sediments. Diagenesis and the transformation of Sediment into Sedimentary Rock 2. Types of Sediments and sedimentary rocks and their textures: a. Clastic Detrital Sediments: are particles or fragments of other materials, such as sand grains. These particles are broken bits of other rocks and/or minerals and can be transported by wind, ice, and water which can influence the shape and characteristics of the particles. These particles get deposited and undergo Diagenesis, which includes the cementing of the particles together to form a rock, such as sandstone. b. Non-Clastic Sediments: i. Chemical Sediments: form through the precipitation of formerly dissolved materials, such as the formation of salt crystals from an evaporating salty lake, to produce rock salt. These rocks often appear crystalline. ii. Biological, Organic Sediments: sediments associated with the accumulation of biological material, such as leaf litter, shells, fossils, coral reefs, etc. These rocks can be fossiliferous and contain many fossils, such as fossiliferous limestone. c. You can sometimes find combinations sediments accumulating in some environments. For example, an accumulation of mud will often form mudstone and shale, but if it contains abundant fossils too, it would be a fossiliferous mudstone or fossiliferous shale. Such a rock would have both clastic and biological material and could have a Bio-clastic texture. 3. As particles are transported, they may be reduced in size and could also undergo rounding and sorting of the particles. Typically, when clastic sediments first form, they may have a jagged, and fragmental appearance, but as they travel, the sharp corners are often knocked off and the particle becomes smaller with smoother, rounded shapes. For example, in a stream, particles will tumble along and become more spherical and uniform in shape. Sorting describes the uniformity of grain sizes in a sedimentary rock. 4. Cementing agents: are typically materials that have formed through chemical weathering reactions to produce dissolved materials that can infiltrate the deposit of sediments and then precipitate in the pore spaces between the sediments and thus bind the particles together, such as dissolved calcite, quartz, or iron oxides. CLASSIFICATION OF SEDIMENTARY ROCKS Clastic / Detrital Sedimentary Rocks Texture / Composition Comments Rock Name particle size Poorly sorted rounded rock CONGLOMERATE Coarse grained Quartz, quartzite, fragments of any rock type. and chert are Poorly sorted angular rock ( >2 mm) dominant BRECCIA fragments of any rock type. Poorly sorted, nonstratified, and Fragments of any angular rock fragments. Coarse to fine rock type Sometimes the larger particles are TILLITE grained (associated with elongate with striations on the flat glaciers) surfaces. Primarily
Recommended publications
  • 17. Clay Mineralogy of Deep-Sea Sediments in the Northwestern Pacific, Dsdp, Leg 20
    17. CLAY MINERALOGY OF DEEP-SEA SEDIMENTS IN THE NORTHWESTERN PACIFIC, DSDP, LEG 20 Hakuyu Okada and Katsutoshi Tomita, Department of Geology, Kagoshima University, Kagoshima 890, Japan INTRODUCTION intensity of montmorillonite can be obtained by sub- tracting the (001) reflection intensity of chlorite from the Clay mineral study of samples collected during Leg 20 of preheating or pretreating reflection intensity at 15 Å. the Deep Sea Drilling Project in the western north Pacific In a specimen with coexisting kaolinite and chlorite, was carried out mainly by means of X-ray diffraction their overlapping reflections make it difficult to determine analyses. Emphasis was placed on determining vertical quantitatively these mineral compositions. For such speci- changes in mineral composition of sediments at each site. mens Wada's method (Wada, 1961) and heat treatment Results of the semiquantitative and quantitative deter- were adopted. minations of mineral compositions of analyzed samples are The following shows examples of the determination of shown in Tables 1, 2, 3, 5, and 7. The mineral suites some intensity ratios of reflections of clay minerals. presented here show some unusual characters as discussed below. The influence of burial diagenesis is also evidenced Case 1 in the vertical distribution of some authigenic minerals. Montmorillonite (two layers of water molecules between These results may contribute to a better understanding silicate layers)—kaolinite mixture. of deep-sea sedimentation on the northwestern Pacific This is the situation in which samples contain both plate. montmorillonite and kaolinite. The first-order basal reflec- tions of these minerals do not overlap. When the (002) ANALYTICAL PROCEDURES reflection of montmorillonite, which appears at about 7 Å, Each sample was dried in air, and X-ray diffraction is absent or negligible, the intensity ratio is easily obtained.
    [Show full text]
  • Mount Apatite Park, Auburn, Maine
    Mount Apatite Park is a 325-acre wooded park located in the western portion of the city. The park offers a wide variety of recreational opportunities not often found in municipal park settings. Rock hounds have known about this area for over 150 years, when the first discoveries of gem-quality tourmaline were found there. Since then, the area has experienced a great deal of mineral exploration, both commercial and amateur. Today amateurs may still search the mine tailings for apatite, tourmaline, and quartz specimens (special rules apply). The park features approximately four miles of trails for non-motorized uses such as hiking, mountain biking, cross-country skiing, and snowshoeing. The Andy Valley Sno Gypsies also maintain a snowmobile trailhead within the park, which links to miles of regional snowmobile trails.The park is open from dawn until dusk year-round. As with all municipal parks, hunting is not allowed within park boundaries. Park brochures, which include a trail map, park rules, and other park information, are available at the Auburn Parks & Recreation Department office, Monday through Friday, 8a.m.-4:30p.m. Mount Apatite Park, Auburn, Maine Significance The Mt. Apatite quarries were important producers of commercial feldspar in the early 1900's. They played a prominent part in Maine's mining history. During the course of this mining activity, rare minerals and colorful crystals of green and pink tourmaline were found in both the Greenlaw and Maine Feldspar Quarries. These quarries also produced many large crystals of transparent smoky quartz. The complexity of the mineral assemblage at Mt.
    [Show full text]
  • Download PDF About Minerals Sorted by Mineral Name
    MINERALS SORTED BY NAME Here is an alphabetical list of minerals discussed on this site. More information on and photographs of these minerals in Kentucky is available in the book “Rocks and Minerals of Kentucky” (Anderson, 1994). APATITE Crystal system: hexagonal. Fracture: conchoidal. Color: red, brown, white. Hardness: 5.0. Luster: opaque or semitransparent. Specific gravity: 3.1. Apatite, also called cellophane, occurs in peridotites in eastern and western Kentucky. A microcrystalline variety of collophane found in northern Woodford County is dark reddish brown, porous, and occurs in phosphatic beds, lenses, and nodules in the Tanglewood Member of the Lexington Limestone. Some fossils in the Tanglewood Member are coated with phosphate. Beds are generally very thin, but occasionally several feet thick. The Woodford County phosphate beds were mined during the early 1900s near Wallace, Ky. BARITE Crystal system: orthorhombic. Cleavage: often in groups of platy or tabular crystals. Color: usually white, but may be light shades of blue, brown, yellow, or red. Hardness: 3.0 to 3.5. Streak: white. Luster: vitreous to pearly. Specific gravity: 4.5. Tenacity: brittle. Uses: in heavy muds in oil-well drilling, to increase brilliance in the glass-making industry, as filler for paper, cosmetics, textiles, linoleum, rubber goods, paints. Barite generally occurs in a white massive variety (often appearing earthy when weathered), although some clear to bluish, bladed barite crystals have been observed in several vein deposits in central Kentucky, and commonly occurs as a solid solution series with celestite where barium and strontium can substitute for each other. Various nodular zones have been observed in Silurian–Devonian rocks in east-central Kentucky.
    [Show full text]
  • Mineralogy, Fluid Inclusion, and Stable Isotope Studies of the Hog Heaven Mining District, Flathead County, Montana
    Montana Tech Library Digital Commons @ Montana Tech Graduate Theses & Non-Theses Student Scholarship Spring 2020 MINERALOGY, FLUID INCLUSION, AND STABLE ISOTOPE STUDIES OF THE HOG HEAVEN MINING DISTRICT, FLATHEAD COUNTY, MONTANA Ian Kallio Follow this and additional works at: https://digitalcommons.mtech.edu/grad_rsch Part of the Geological Engineering Commons MINERALOGY, FLUID INCLUSION, AND STABLE ISOTOPE STUDIES OF THE HOG HEAVEN MINING DISTRICT, FLATHEAD COUNTY, MONTANA by Ian Kallio A thesis submitted in partial fulfillment of the requirements for the degree of Masters of Science in Geoscience Geology Option Montana Tech 2020 ii Abstract The Hog Heaven mining district in northwestern Montana is unique in that it is a high- sulfidation epithermal system containing high Ag-Pb-Zn relative to Au-Cu, with a very high Ag to Au ratio (2,330:1). The deposits are hosted within the Cenozoic Hog Heaven volcanic field (HHVF), a 30 to 36 Ma suite that consists predominantly of rhyodacite flow-dome complexes and pyroclastic rocks. The HHVF is underlain by shallow-dipping siliclastic sediments of the Mesoproterozoic Belt Supergroup. These sediments are known to host important SEDEX (e.g., Sullivan) and red-bed copper (e.g., Spar Lake, Rock Creek, Montanore) deposits rich in Ag-Pb- Zn-Cu-Ba. The HHVF erupted through and deposited on the Belt strata during a period of Oligocene extension. Outcrops and drill core samples from Hog Heaven show alteration patterns characteristic of volcanic-hosted, high-sulfidation epithermal deposits. Vuggy quartz transitions laterally into quartz-alunite alteration where large sanidine phenocrysts (up to 4 cm) have been replaced by fine-grained, pink alunite, and/or argillic alteration that is marked by an abundance of white kaolinite-dickite clay.
    [Show full text]
  • Bedrock Geology Glossary from the Roadside Geology of Minnesota, Richard W
    Minnesota Bedrock Geology Glossary From the Roadside Geology of Minnesota, Richard W. Ojakangas Sedimentary Rock Types in Minnesota Rocks that formed from the consolidation of loose sediment Conglomerate: A coarse-grained sedimentary rock composed of pebbles, cobbles, or boul- ders set in a fine-grained matrix of silt and sand. Dolostone: A sedimentary rock composed of the mineral dolomite, a calcium magnesium car- bonate. Graywacke: A sedimentary rock made primarily of mud and sand, often deposited by turbidi- ty currents. Iron-formation: A thinly bedded sedimentary rock containing more than 15 percent iron. Limestone: A sedimentary rock composed of calcium carbonate. Mudstone: A sedimentary rock composed of mud. Sandstone: A sedimentary rock made primarily of sand. Shale: A deposit of clay, silt, or mud solidified into more or less a solid rock. Siltstone: A sedimentary rock made primarily of sand. Igneous and Volcanic Rock Types in Minnesota Rocks that solidified from cooling of molten magma Basalt: A black or dark grey volcanic rock that consists mainly of microscopic crystals of pla- gioclase feldspar, pyroxene, and perhaps olivine. Diorite: A plutonic igneous rock intermediate in composition between granite and gabbro. Gabbro: A dark igneous rock consisting mainly of plagioclase and pyroxene in crystals large enough to see with a simple magnifier. Gabbro has the same composition as basalt but contains much larger mineral grains because it cooled at depth over a longer period of time. Granite: An igneous rock composed mostly of orthoclase feldspar and quartz in grains large enough to see without using a magnifier. Most granites also contain mica and amphibole Rhyolite: A felsic (light-colored) volcanic rock, the extrusive equivalent of granite.
    [Show full text]
  • Geology and Hydrothermal Alteration of the Duobuza Goldrich Porphyry
    doi: 10.1111/j.1751-3928.2011.00182.x Resource Geology Vol. 62, No. 1: 99–118 Thematic Articlerge_182 99..118 Geology and Hydrothermal Alteration of the Duobuza Gold-Rich Porphyry Copper District in the Bangongco Metallogenetic Belt, Northwestern Tibet Guangming Li,1 Jinxiang Li,1 Kezhang Qin,1 Ji Duo,2 Tianping Zhang,3 Bo Xiao1 and Junxing Zhao1 1Key Laboratory of Mineral Resources, Institute of Geology and Geophysics, CAS, Beijing, 2Tibet Bureau of Geology and Exploration, Lhasa, Tibet and 3No. 5 Geological Party, Tibet Bureau of Geology and Exploration, Golmu, China Abstract The Duobuza gold-rich porphyry copper district is located in the Bangongco metallogenetic belt in the Bangongco-Nujiang suture zone south of the Qiangtang terrane. Two main gold-rich porphyry copper deposits (Duobuza and Bolong) and an occurrence (135 Line) were discovered in the district. The porphyry-type mineralization is associated with three Early Cretaceous ore-bearing granodiorite porphyries at Duobuza, 135 Line and Bolong, and is hosted by volcanic and sedimentary rocks of the Middle Jurassic Yanshiping Formation and intermediate-acidic volcanic rocks of the Early Cretaceous Meiriqie Group. Simultaneous emplacement and isometric distribution of three ore-forming porphyries is explained as multi-centered mineralization generated from the same magma chamber. Intense hydrothermal alteration occurs in the porphyries and at the contact zone with wall rocks. Four main hypogene alteration zones are distinguished at Duobuza. Early-stage alteration is dominated by potassic alteration with extensive secondary biotite, K-feldspar and magnetite. The alteration zone includes dense magnetite and quartz-magnetite veinlets, in which Cu-Fe-bearing sulfides are present.
    [Show full text]
  • A POST IMPACT VOLCANISM SCENARIO for the FORMATION of the OLIVINE-RICH UNIT in the REGION of NILI FOSSAE, MARS. L. Mandon1, C. Q
    49th Lunar and Planetary Science Conference 2018 (LPI Contrib. No. 2083) 1473.pdf A POST IMPACT VOLCANISM SCENARIO FOR THE FORMATION OF THE OLIVINE - RICH UNIT IN THE REGION OF NILI FOSSAE, MARS. L. Mandon 1 , C. Quantin 1 , P. Thollot 1 , L. Lozac’h 1 , N. Mangold 2 , G. Dromart 1 , P. Beck 3 , E. Dehouck 1 , S. Breton 1 , C. Millot 1 . 1 Laboratoire de Géologie de Lyon Terre, Planètes, Environnement , Université de Lyon, France. 2 Laboratoire de Planétologie et Géodynamique , Université de Nantes, France. 3 Institut de Planétologie et d'Astrophysique de Gre- noble , Université Grenoble Alpes, France. lucia.ma ndon@univ - lyon1.fr. Introduction: The Nili Fossae region exhibits the gets using MarsSI. We used HRSC DTMs computed largest Martian exposures of olivine - rich materials, as by the Fr eie Universitaet Berlin and DLR Berlin . deduced from orbital near - infrared and thermal spec- Strikes and dips measurements were performed using troscopy [1, 2] . Several hypotheses have been pro- the ArcGIS extension LayerTools [7]. Finally, we posed to explain the origin of a widespread olivine - rich performed crater size analyses on both small (~1 km²) formati on in the region: (1) these materials might be and wide (~900 km²) olivine - rich areas. Using the crustal rocks excavated by the giant impact leading to Craterstats software [8], we compared size distribu- the formation of Isidis Planitia [2], a 1200 km wide tions to isochrons generated by the Ivanov production impact basin east of Nili Fossae. (2) They could result function to estimate a surface age [9]. from mafic effusive lava flows occurring befo re [3] or Results: At HiRISE resolution, the unit appears after [4] the giant impact.
    [Show full text]
  • Economic Geology Report ER79-4: Porphyritic Intrusions and Related
    MANITOBA CANADA DEPARTMENT OF ENERGY AND MINES MANITOBA MINERAL RESOURCES DIVISION ECONOMIC GEOLOGY REPORT ER79-4 PORPHYRITIC INTRUSIONS AND RELATED MINERALIZATION IN THE FLIN FLON VOLCANIC BELT by D.A. BALDWIN 1980 Funding for this project was provided under the cost-shared Canada-Manitoba Non-renewable Resources Evaluation Program by the Canada Department of Energy, Mines and Resources and the Manitoba Department of Mines, Resources and Environmental Management. MANITOBA DEPARTMENT OF ENERGY AND MINES HON. DONALD W. CRAIK PAUL E. JARVIS Minister Deputy Minister MINERAL RESOURCES DIVISION IAN HAUGH Executive Director ECONOMIC GEOLOGY REPORT ER79-4 PORPHYRITIC INTRUSIONS AND RELATED MINERALIZATION IN THE FLIN FLON VOLCANIC BELT by D.A. BALDWIN 1980 LEGEND I Cliff Lake Stock 5 Elbow Lake Stock 2 Whitefish Lake Porphyry 6 Fourmile Island Intrusion 3 Alberts Lake Intrusion 7 Chisel Lake Intrusion 4 Nisto Lake Intrusion 8 Wekusko Lake Intrusion ,~ -./ - -, I \." ~herridon '" , ;. <,.... ,1 if 55°00' 55°00' c, t,:) ,J -3 , I"" . c;? '" 1[' . ::t} \'''If!? ~,/J~ /j' ., ~), F lin.~ i;\))F ' I,".!0l~' ,d ' ;)/", ' ~.;'. l ;' ~" ,r~n ;t j; (I:/,1 ,r Lake ' \\ ;\~ ' ~i'/ 'lUi':;- -'i' //{ ,'/ , ,\" ,,/,1,1 pI , .h .(,1;' '\:. (IiI' ' .. '~'4_hl i / 'Y{j,'{:" 5 2.5 a 10 15 KILOMETRES J!) "'.t3 f3,F-"\ ---- :i~ f)J~c~. V 99°30' ">/)AfhapaplJskoj¥ !ZJ Porphyritic Intrusive Rocks 54°30' ! ,1 Lake .; ... 100°30' D Felsic Volcanic Rocks FIGURE 1: Distribution of porphyritic intrusive and felsic volcanic rocks in the Flin Flon volcanic belt, TABLE OF
    [Show full text]
  • Module 7 Igneous Rocks IGNEOUS ROCKS
    Module 7 Igneous Rocks IGNEOUS ROCKS ▪ Igneous Rocks form by crystallization of molten rock material IGNEOUS ROCKS ▪ Igneous Rocks form by crystallization of molten rock material ▪ Molten rock material below Earth’s surface is called magma ▪ Molten rock material erupted above Earth’s surface is called lava ▪ The name changes because the composition of the molten material changes as it is erupted due to escape of volatile gases Rocks Cycle Consolidation Crystallization Rock Forming Minerals 1200ºC Olivine High Ca-rich Pyroxene Ca-Na-rich Amphibole Intermediate Na-Ca-rich Continuous branch Continuous Discontinuous branch Discontinuous Biotite Na-rich Plagioclase feldspar of liquid increases liquid of 2 Temperature decreases Temperature SiO Low K-feldspar Muscovite Quartz 700ºC BOWEN’S REACTION SERIES Rock Forming Minerals Olivine Ca-rich Pyroxene Ca-Na-rich Amphibole Na-Ca-rich Continuous branch Continuous Discontinuous branch Discontinuous Biotite Na-rich Plagioclase feldspar K-feldspar Muscovite Quartz BOWEN’S REACTION SERIES Rock Forming Minerals High Temperature Mineral Suite Olivine • Isolated Tetrahedra Structure • Iron, magnesium, silicon, oxygen • Bowen’s Discontinuous Series Augite • Single Chain Structure (Pyroxene) • Iron, magnesium, calcium, silicon, aluminium, oxygen • Bowen’s Discontinuos Series Calcium Feldspar • Framework Silicate Structure (Plagioclase) • Calcium, silicon, aluminium, oxygen • Bowen’s Continuous Series Rock Forming Minerals Intermediate Temperature Mineral Suite Hornblende • Double Chain Structure (Amphibole)
    [Show full text]
  • Clay Minerals Soils to Engineering Technology to Cat Litter
    Clay Minerals Soils to Engineering Technology to Cat Litter USC Mineralogy Geol 215a (Anderson) Clay Minerals Clay minerals likely are the most utilized minerals … not just as the soils that grow plants for foods and garment, but a great range of applications, including oil absorbants, iron casting, animal feeds, pottery, china, pharmaceuticals, drilling fluids, waste water treatment, food preparation, paint, and … yes, cat litter! Bentonite workings, WY Clay Minerals There are three main groups of clay minerals: Kaolinite - also includes dickite and nacrite; formed by the decomposition of orthoclase feldspar (e.g. in granite); kaolin is the principal constituent in china clay. Illite - also includes glauconite (a green clay sand) and are the commonest clay minerals; formed by the decomposition of some micas and feldspars; predominant in marine clays and shales. Smectites or montmorillonites - also includes bentonite and vermiculite; formed by the alteration of mafic igneous rocks rich in Ca and Mg; weak linkage by cations (e.g. Na+, Ca++) results in high swelling/shrinking potential Clay Minerals are Phyllosilicates All have layers of Si tetrahedra SEM view of clay and layers of Al, Fe, Mg octahedra, similar to gibbsite or brucite Clay Minerals The kaolinite clays are 1:1 phyllosilicates The montmorillonite and illite clays are 2:1 phyllosilicates 1:1 and 2:1 Clay Minerals Marine Clays Clays mostly form on land but are often transported to the oceans, covering vast regions. Kaolinite Al2Si2O5(OH)2 Kaolinite clays have long been used in the ceramic industry, especially in fine porcelains, because they can be easily molded, have a fine texture, and are white when fired.
    [Show full text]
  • Lab 2: Silicate Minerals
    GEOLOGY 640: Geology through Global Arts and Artifacts LAB 2: SILICATE MINERALS FRAMEWORK SILICATES The framework silicates quartz and feldspar are the most common minerals in Earth’s crust. Quartz (SiO 2) is one of the few common minerals that is harder than a streak plate. It may display numerous colors (purple= amethyst ; pink= rose quartz ; brown= smoky quartz ; yellow-orange= citrine ). It may form long hexagonal crystals but lacks cleavage, and instead breaks along irregular, curving surfaces (conchoidal fracture). In many cases quartz forms masses of microscopic crystals (e.g., chert, flint, chalcedony ) that still maintain the hardness and conchoidal fracture of quartz. Banded chalcedony is called agate , whereas reddish chalcedony is called carnelian (bloodstone). Plagioclase is a group of feldspar minerals that have complete solid solution from NaAlSi 3O8 ( albite ) to CaAl 2Si 2O8 ( anorthite ). Na-rich plagioclase tends to white in hands sample, whereas Ca-rich plagioclase tends to be dark grey. Twinning is the intergrowth of two or more crystals in a symmetrical fashion by the sharing of lattice points in adjacent crystals. In plagioclase, the most common twins are planar and repeated (polysynthetic twinning), resulting in the striations that are characteristic of plagioclase in hand-sample. Twinning tends to be better developed in Ca-plagioclase minerals. Ca-rich plagioclase (labradorite and anorthite) may also display iridescent colors (mostly blue). Iridescent albite is rare and is known as the semi-precious gem moonstone . Microcline (KAlSi 3O8) is the most common alkali feldspar. It is similar to plagioclase in most of its optical properties (hard, blocky, 2 cleavages at 90°).
    [Show full text]
  • Plagioclase Peridotite Or Olivine- Plagioclase Assemblage In
    Plagioclase peridotite or olivine- plagioclase assemblage in orogenic peridotites: its implications on high-temperature decompression of the subcontinental lithosphere- asthenosphere boundary zone K. Ozawa, Univ. Tokyo; C. J. Garrido, Univ. Granada; K. Hidas, Univ. Granada; J-L. Bodinier, Geosciences Montpellier; T. Aoki, Univ. Tokkyo; F. Boudier, Univ. Montpellier EGU, Vienna, 6 May, 2020 1 What we did in this study. • We have examined four orogenic peridotite complexes, Ronda, Pyrenees, Lanzo, and Horoman, to clarify the extent of shallow thermal processing based on olivine-plagioclase assemblage in plagioclase lherzolite. • The key approach of this study is to look at textural relationships between olivine and plagioclase, whose scale and mode of occurrence provide extent and strength of thermal processing in the shallow upper mantle and thus asthenosphere activity related to the exhumation of lithospheric mantle. 2 Plagioclase lherzolite proxy for dynamics of LAB • Plagioclase (pl) -olivine (ol) assemblage in fertile system is not stable even at the depth of the upper most subcontinental lithospheric mantle (SCLM ) because ….. (1) The common crustal thickness in normal non-cratonic SCLM is ~35km. (2) The Moho temperature for the mean steady-state continental geotherm is much lower than 600°C. (3) The upper stability limit of plagioclase (plagioclase to spinel facies transition) becomes shallower with decrease in temperature. (4) Kinetic barrier for subsolidus reactions in the peridotite system becomes enormous at temperatures below
    [Show full text]