Pdf tectonic magnetic lineation and oroclinal bending of. Intersection lineations are measured in relation to the two structures which intersect to form them. Foliation is exhibited most prominently by sheety minerals, such as mica or chlorite. Ppt analysis of lineation and foliation rudra mohan. This sl fabric probably corresponds to the d1 structural elements. If n mf is the universal covering of m and f is the covering projection f. Choose from 81 different sets of foliation flashcards on quizlet. The major premaximum lineation sets which differ in orientation from the retreat sets. To qualify as a foliation or lineation, a structure must be penetrative within a volume that has a dimension on the order of tens of centimeters. Significance of composite lineations in the mid to deep.
Lineation is usually defined by a preferred orientation of mineral grains that are elongated in the plane of foliation, but it can also result from the intersection of two planar features, such as a plane of foliation with a plane of layering. The term unfoliated gneiss is coined to describe such gneissic rocks with lineation alone and without. Ppt foliation and lineation powerpoint presentation. Pdf foliation development and refraction in metamorphic rocks. The lineation is characterized by elongated enstatite, olivine and poikiloblastic garnet. Geological background, rock mechanics significance, and preliminary investigations at olkiluoto abstract a well developed, pervasive foliation is a characteristic feature of the migmatites and gneisses in the olkiluoto bedrock, and.
A moderately to steeply west to southwestplunging mineral lineation is commonly defined by elongate actinolitebiotite aggregates. Primary foliation and lineation foliations and lineations are primary if they were origenated by primary sedimentary and igneous process i. If related to shear on these surfaces, we might expect to see a stretching lineation oriented at high angle to the fold axis. Bell and others published foliation development and refraction in. If f is a submersion and f is the foliation by points, f is transverse to f.
If so, these fabrics record a late devonian crustalscale strikeslip stress regime that may also have driven dextral movement on the neighboring. Foliation definition of foliation by the free dictionary. Lineation may be defined in a more precise way as any linear fabric element. The cascades core exposes a cretaceous to paleogene continental magmatic arc and is the southern continuation of the coast plutonic complex. They tend to be preserved in areas which lay beneath the principal ice divide at the maximum of glaciation, which protected them from erosion because of frozen bed conditions and low ice velocities boulton et al. Discussion on the structural interpretation of domainal. Figure 1b shows the lineation plotted on the stereonet.
En echelon arrays of sigmoidal extensional veins can occur as the single vein type within the shear zone fig. Draw a line representing the strike line of the plane. Foliation in feldsparrich metamorphic rock, formed at intermediate to high. It is the branch of geology that studies the 3d geometry from micro to macro scale of rocks to explain the deformation processes the rocks experienced since their origination. Analysis and interpretation of foliation and lineation 1. The equivalence classes are called the leaves of the foliation. Relates the physical and geometric elegance of geologic structures within the earths crust and the ways in which these structures reflect the nature and origin of crystal deformation through time. As shown in this example, one characteristic of slate foliation is the way in which these parallel lines appear in the rock. Relationship of foliation to folds lineation classification form lineations, surfacelineations, and mineral lineations conclusion references 31082012 2. Magmatic lineation and foliation formed in the mount waldo pluton during its late devonian crystallization in response to a small increment of regional crustal strain. Aug 12, 2017 lineation may be defined in a more precise way as any linear fabric element. Foliation forms what mineral grains orient themselves in such a way that they create repetitive planar structures. For instance, according to the measurement conventions of structural geology, original bedding, s 0 intersected by a folds axial plane foliation, forms an intersection lineation l 01, with an azimuth and. Lineation is usually defined by a preferred orientation of mineral grains that are elongated in the plane of foliation, but it can also result from the intersection of two planar features, such as a.
Foliation geometrytopology problem set steven hurder contents 1. Foliation boudinage is a form of boudinage that develops in foliated rocks independent of lithology contrast. This foliation and lineation represent the accentuated ls fabric inherited from the. Caused by reorientation of the crystalline fabric of the minerals. What is the difference between lineation and foliation in. Preliminary structural study of the goldbearing shear. In this paper, the notion of a distribution will be presented which makes it possible for in. Oct 23, 2016 lineation homogeneous distributed linear structure i. There is no or only weak lineation ltectonite alignment of linear fabric elements creates the dominant fabric, so the rock may split into rodlike shapes. Analysis and interpretation of foliation and lineation. Origin of striping lineation and transposition of linear. Foliation and lineation 1 foliation and lineation goal to interpret some common types of foliation and lineation in deformed rocks 2 foliation mesoscopically penetrative subparallel alignment of planar fabric elements in a rock. A free powerpoint ppt presentation displayed as a flash slide show on id.
A thorough presentation on characteristics and description of all main types of metamorphic rocks. Introduction to structural geology and lecture notes. Ppt foliation and lineation powerpoint presentation free. Glg310 structural geology cleavage, foliation, lineation rock fabric. Isik journal of asian earth sciences 34 2009 507521 5. There is a fine stretching lineation parallel to striping. On account of the parallel disposition of the elongated clusters of dark and light mineral constituents in alternate bands, the nepheline syenites have been rendered gneissose. The word comes from the latin folium, meaning leaf, and refers to the sheetlike planar structure. Architecture decoration of an opening with cusps and foils, as in. Foliation development and refraction in metamorphic rocks. Get here to download pdf ebook 08176399geometrictheoryoffoliations. Olivine shows a very unusual lpo with 100 normal to foliation and 001 parallel to lineation. Its best observed on a surface perpendiculat to foliation layers, because one can see those multiple layers. Apr 07, 2017 analysis and interpretation of foliation and lineation 1.
Pdf the ductile shear zone in granitoid of the central. Ppt foliation powerpoint presentation free to view id. Pdf controls in lineation development in low to medium. The eocene, dextral straight creek fault separates the cascades core from lowgrade paleozoic and mesozoic oceanic and arc rocks to the west that were involved in the midcretaceous northwest cascades thrust system fig. Geometric relationships which result from reactivation of foliations around porphyroblasts can be used to aid determination of the timing of the growth.
From this small strain, we infer the late devonian maximum principal stress. The origin of foliation and lineation in the onaping. Foliations, lineations and lattice preferred orientation. Vein formation and deformation in greenstone gold deposits. In such arrays, the individual veins are generally small, less than 10 cm thick, and lie at a high angle to the foliation and lineation in the host shear zone if present figs. Foliation in geology refers to repetitive layering in metamorphic rocks. This is a form of intersection lineation manifested in fine banding, considered to be the intersection of one domainal foliation e.
Foliation definition is the process of forming into a leaf. Geology the arrangement of the constituents of a rock in leaflike layers, as in. Scribd is the worlds largest social reading and publishing site. Foliations are subdivided into primary and secondary ones, the first being of. In a recent short note, lisle 20 uses an example from the new harbour group of anglesey, uk, to illustrate a type of structural lineation he terms domainal trace lineation. Fabric is used to describe the spatial and geometric relationships that make up the rock. More commonly, stretch ing lineations are parallel to the fold axis. Geology foliation and lineation symbols geonet, the esri. These elements formed not by shearing, as previously supposed, but by flowage such that maximum shortening was normal to the foliation and maximum. It is caused by shearing forces pressures pushing different sections of the rock in different directions, or differential pressure higher. Preliminary structural study of the goldbearing shear zone.
The main thrust is on applications in regional tectonics, exploration geology, active tectonics and geohydrology. The act of beating a metal into a thin plate, leaf, foil, or lamina. Use ball indicating known top direction of layers only on maps where top direction may be in doubt elsewhere. An introduction to distributions and foliations samuel otten michigan state university mth 864 spring 2008 in smooth manifold theory, the notion of a tangent space makes it possible for di. Nanotexture of penetrative foliation in metamorphic rocks. A decomposition of into pathconnected subsets, called leaves, such that can be covered by coordinate neighbourhoods with local coordinates, in terms of which the local leaves, that is, the connected components of the intersection of the leaves with, are given by the equations. Combines mineral shapepreferred orientation and compositional banding. Its eventual goal is to describe the classifying space for codlmenslon g foliated manifolds which has recently been constructed by. These include fractures, faults, folds, boudins, shear zones, cleavages also knows as schistosities, foliations and lineations. Total sum of grain shape, grain size, and grain configuration in a rock. Noun lb the process of forming into a leaf or leaves. Foliation article about foliation by the free dictionary.
The authors have recognized strong lineation in the nepheline syenites of khammam district, andhra pradesh. Foliation definition of foliation by merriamwebster. Structural geology of rocks and regions, 3rd edition wiley. Lstectonite a strong foliation and a strong lineation. The stretching lineation in a reactivated foliation can be radically reoriented, potentially causing major errors in determining movement directions in mylonitic schistosities in folded thrusts.
Mosaic texture of equidimensional, anhedral grains. Each layer can be as thin as a sheet of paper, or over a meter in thickness. Metamorphic rocks presentation free download as powerpoint presentation. Table 1 determining view of the nanotexture of penetrative foliation in both regional metamorphic rocks and dynamic. This process is called folio numbering or foliation. Cleavage, foliation, lineation linkedin slideshare. Foliations, lineations and lattice preferred orientation springerlink. The trace of bedding on an intersecting foliation plane commonly appears as color stripes generally parallel to local fold axes hence it is sometimes called strip ing lineation.
Lineation means that all the linear minerals or structures are lying parallel, like a stack of logs. Techniques, experiments, and calculations are described in detail, with the purpose. For centuries, however, manuscript curators have been numbering the recto of each leaf to facilitate study and conservation. Typically, the flyleaves of a book are foliated with roman numerals, and arabic. The scribes and printers who produced these books didnt number the individual pages.
The planar foliation and straight lineation in the farfield wall rock are deflected close to the central discontinuity, and the typical shape of a foliation boudinage structure as described below is defined by the deflection pattern of the foliation, and the shape of the central veins. Controls in lineation development in low to medium grade shear zones. It is caused by shearing forces pressures pushing different sections of the rock in different. Any penetrative set of more or less parallel lines. Lineation homogeneous distributed linear structure i. A foliation in this sense is called a topological foliation. A lineation defined by the hinges of small folds crenulations associated with crenulation cleavage.
Detailed study of the bingo north and bingo south gold. Foliation definition and meaning collins english dictionary. A penetrative secondary foliation and lineation, defined by tectonically flattened and elongated fragments, are present in the onaping formation of the south and east ranges of the sudbury basin. The act of coating with an amalgam of tin foil and quicksilver, as in making lookingglasses. Near where i live there is a metaconglomerate where the individual clasts are 2cm wide and thick, but up to 100cm long. The orientation of the lineation and foliation is consistent with their formation due to a small increment of crustalscale strain absorbed by the pluton in its geologically brief magmatic state. Nordkalott project, 1986 in southwestern sweden, the residuals show a northsouth trend compared with the nesw. Because of the low temperatures and pressure, we can label this type of. The mylonitic rock is composed of alternate calcareous and siliciclastic bands. Pdf an increasing number of structural and metamorphic studies throughout. The internal penetrative foliation is generally subparallel to the shear zone boundaries figure 3b. Foliations lineations free download as powerpoint presentation. Introduction foliation foliation includes significanceof foliation primary foliation diagenetic foliation secondary foliation two general typesof foliation.
Abundant platy minerals chlorite, biotite, etc with strong preferred orientation. Sm generally dips steeply west 65 and contains a weakly developed, moderately northwestplunging hornblendebiotite lineation. Two nonparallel foliations can also produce an i ntersection lineation. Foliation of this latter kind normally lacks lineation jackson, 1961. Foliations lineations rocks chemical product engineering. Pdf the significance and application of foliation intersection. Deformation partitioning and foliation reactivation during. Nanotexture of penetrative foliation in metamorphic. Foliations, lineations and lattice preferred orientation 4.
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