On the Old Red Sandstone and Carboniferous Rocks Of
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Mechanical Stratigraphic Controls on Natural Fracture Spacing and Penetration
Journal of Structural Geology 95 (2017) 160e170 Contents lists available at ScienceDirect Journal of Structural Geology journal homepage: www.elsevier.com/locate/jsg Mechanical stratigraphic controls on natural fracture spacing and penetration * Ronald N. McGinnis a, , David A. Ferrill a, Alan P. Morris a, Kevin J. Smart a, Daniel Lehrmann b a Department of Earth, Material, and Planetary Sciences, Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78238-5166, USA b Geoscience Department, Trinity University, One Trinity Place, San Antonio, TX 78212, USA article info abstract Article history: Fine-grained low permeability sedimentary rocks, such as shale and mudrock, have drawn attention as Received 20 July 2016 unconventional hydrocarbon reservoirs. Fracturing e both natural and induced e is extremely important Received in revised form for increasing permeability in otherwise low-permeability rock. We analyze natural extension fracture 21 December 2016 networks within a complete measured outcrop section of the Ernst Member of the Boquillas Formation Accepted 7 January 2017 in Big Bend National Park, west Texas. Results of bed-center, dip-parallel scanline surveys demonstrate Available online 8 January 2017 nearly identical fracture strikes and slight variation in dip between mudrock, chalk, and limestone beds. Fracture spacing tends to increase proportional to bed thickness in limestone and chalk beds; however, Keywords: Mechanical stratigraphy dramatic differences in fracture spacing are observed in mudrock. A direct relationship is observed be- Natural fractures tween fracture spacing/thickness ratio and rock competence. Vertical fracture penetrations measured Fracture spacing from the middle of chalk and limestone beds generally extend to and often beyond bed boundaries into Fracture penetration the vertically adjacent mudrock beds. -
How Do Sedimentary Beds Form? – and Why Can We See Them? Demonstrating How the Beds in Sedimentary Rocks Are Deposited
Earthlearningidea – https://www.earthlearningidea.com How do sedimentary beds form? – and why can we see them? Demonstrating how the beds in sedimentary rocks are deposited Sedimentary rock layers are called beds, if they are more than 1 cm thick*. Each bed was laid down by a single sedimentary event, so the beds in the photo below were laid down by many, many separate events of sand deposition. The junction between beds is called a bedding plane and is normally a flat horizontal surface. Bedding in a measuring cylinder, with sands of different colour on the left and sands of one colour (but added in several sedimentary episodes or spoonfuls) on the right. (Chris King). So, later when the sands have been compacted and cemented to form sandstones, the slight Bedding in 140 million year old sedimentary rocks, Morro differences between the top of one bed and the Solar, Lima, Peru. This series of beds has been tilted by bottom of another remain. These are later tectonic forces. attacked by weathering and erosion so that the Image licensed by Miguel Vera León under the Creative bedding plane and the beds can be seen. Commons Attribution 2.0 Generic license. Bedding planes are even clearer if there was an You can make your own beds by filling a 2 interval of time between the laying down of the measuring cylinder /3 full of water and adding upper and lower beds. In that time interval, the spoonfuls of sand. Each spoonful you add is a lower bed may have become more compacted, or single sedimentary episode and the junction partially eroded or sedimentary structures like between each layer is a bedding plane. -
Stratigraphical Framework for the Devonian (Old Red Sandstone) Rocks of Scotland South of a Line from Fort William to Aberdeen
Stratigraphical framework for the Devonian (Old Red Sandstone) rocks of Scotland south of a line from Fort William to Aberdeen Research Report RR/01/04 NAVIGATION HOW TO NAVIGATE THIS DOCUMENT ❑ The general pagination is designed for hard copy use and does not correspond to PDF thumbnail pagination. ❑ The main elements of the table of contents are bookmarked enabling direct links to be followed to the principal section headings and sub-headings, figures, plates and tables irrespective of which part of the document the user is viewing. ❑ In addition, the report contains links: ✤ from the principal section and sub-section headings back to the contents page, ✤ from each reference to a figure, plate or table directly to the corresponding figure, plate or table, ✤ from each figure, plate or table caption to the first place that figure, plate or table is mentioned in the text and ✤ from each page number back to the contents page. Return to contents page NATURAL ENVIRONMENT RESEARCH COUNCIL BRITISH GEOLOGICAL SURVEY Research Report RR/01/04 Stratigraphical framework for the Devonian (Old Red Sandstone) rocks of Scotland south of a line from Fort William to Aberdeen Michael A E Browne, Richard A Smith and Andrew M Aitken Contributors: Hugh F Barron, Steve Carroll and Mark T Dean Cover illustration Basal contact of the lowest lava flow of the Crawton Volcanic Formation overlying the Whitehouse Conglomerate Formation, Trollochy, Kincardineshire. BGS Photograph D2459. The National Grid and other Ordnance Survey data are used with the permission of the Controller of Her Majesty’s Stationery Office. Ordnance Survey licence number GD 272191/2002. -
B-127 Lithostratigraphic Framework Of
&A 'NlOO,G-3 &i flo, 12 7 g l F£i&f THE LITHOSTRATIGRAPHIC FRAMEWORK OF \;\ .-t "- THE UPPERMOST CRETACEOUS AND LOWER TERTIARY OF EASTERN BURKE COUNTY, GEORGIA Paul F. Huddlestun and Joseph H. Summerour Work Performed in Cooperation with United States Geological Survey (Cooperative Agreement Number 1434-92-A-0959) and U. S. Department of Energy (Cooperative Agreement Number DE-FG-09-92SR12868) GEORGIA DEPARTMENT OF NATURAL RESOURCES ENVIRONMENTAL PROTECTION DIVISION GEORGIA GEOLOGIC SURVEY Atlanta 1996 Bulletin 127 THE LITHOSTRATIGRAPHIC FRAMEWORK OF THE UPPERMOST CRETACEOUS AND LOWER TERTIARY OF EASTERN BURKE COUNTY, GEORGIA Paul F. Huddlestun and Joseph H. Summerour GEORGIA DEPARTMENT OF NATURAL RESOURCES Lonice C. Barrett, Commissioner ENVIRONMENTAL PROTECTION DIVISION Harold F. Reheis, Director GEORGIA GEOLOGIC SURVEY William H. McLemore, State Geologist Atlanta 1996 Bulletin 127 ABSTRACT One new formation, two new members, and a redefinition of an established lithostratigraphic unit are formally introduced here. The Oconee Group is formally recognized in the Savannah River area and four South Carolina Formations not previously used in Georgia by the Georgia Geologic Survey are recognized in eastern Burke County. The Still Branch Sand is a new formation and the two new members are the Bennock Millpond Sand Member of the Still Branch Sand and the Blue Bluff Member of the Lisbon Formation. The four South Carolina formations recognized in eastern Burke CountY include the Steel Creek Formation and Snapp Formation of the Oconee Group, the Black Mingo Formation (undifferentiated), and the Congaree Formation. The Congaree Formation and Still Branch Sand are considered to be lithostratigraphic components of the Claiborne Group. -
GY 111 Lecture Notes Bed Attitude (AKA – Strike and Dip)
GY 111 Lecture Notes D. Haywick (2008-09) 1 GY 111 Lecture Notes Bed Attitude (AKA – Strike and Dip) Lecture Goals: A) Beds in 3D space; the problem of orientation B) Strike and Dip C) Geological maps 1: horizontal and inclined bedding on map* Reference: Press et al., 2004, Chapter 11; Grotzinger et al., 2007, Chapter 7; p 152-154 GY 111 Lab manual Chapter 5 A) Beds in 3D space; the problem of orientation Up until now, I have been illustrating just about every important geological concept in two dimensions. For example, in the last lecture, I illustrated the Principle of Superposition with the adjacent cartoon: The thing is that beds are planes not lines and therefore, I really should have used a three dimensional or perspective cartoon to illustrate superposition. This one is more realistic, albeit a bit more annoying to draw on the fly during a lecture: GY 111 Lecture Notes D. Haywick (2008-09) 2 If you think about it, it is relatively easy to describe the orientation of horizontal bedding. All you have to say is "horizontal" and everyone immediately visualizes a flat surface ( e.g., a table, the floor, etc.). But we have a serious problem when it comes to describing the orientation of an inclined bed. Picture a tilted plane like the one drawn in the next cartoon. Were you to just say that the bed is inclined, every insightful person that you met (e.g., your fellow GY 111 classmates) would ask, "how much and in which direction?" After all, each of the beds in the next cartoon is inclined, but every one is inclined differently. -
SW Science 10 Unit 6 Relative Dating Worksheet
SW Science 10 Unit 6 Relative Dating Worksheet Name: __________________________________ Student #: ____________ 6.2 Geologic Time 6.2.2 Relative Dating The Law of Superposition In any undisturbed sequence of strata, the oldest layer is at the bottom of the sequence, and the youngest layer is at the top of the sequence. The Cross-Cutting Law Any feature that cuts across a body of sediment or rock is younger than the body of sediment or rock that it cuts across. NOTE: • A fracture is a crack in rock. • A fault is a fracture along which movement has occurred. The Law of Inclusions If one rock body contains fragments of another rock body it must be younger than the fragments of rock it contains. OR…The inclusions are older than the rocks which contain them. Inclusions Inclusions of B are older than C. Page 2 Telling Relative Time Use the laws of superposition, inclusions and cross-cutting relationships to determine the relative ages of the following cross-sections. Determine the OLDEST bed FIRST. 1 2 3 SW SC10 UNIT 6 Earth Forces Relative Dating WS Page 3 H G F E C D B A 4 M 5 Outline the sequence of events in the cross sections below by numbering each rock unit or event in the order in which it occurred or was deposited. Youngest ________ ________ ________ ________ 6 Oldest ________ E SW SC10 UNIT 6 Earth Forces Relative Dating WS Page 4 C Refer to the cross-section on the left. For each of the following pairs of rock layers, identify the relative dating law that would be used to determine which bed was older and which was younger. -
Primary Sedimentary Structures in Some Metamorphic Rocks
Sedimentary Structures in Metamorphic Rocks Maine Geological Survey Maine Geologic Facts and Localities November, 2006 Primary Sedimentary Structures in Some Metamorphic Rocks Text by Thomas K. Weddle Maine Geological Survey, Department of Agriculture, Conservation & Forestry 1 Sedimentary Structures in Metamorphic Rocks Maine Geological Survey Introduction In most introductory geology classes, be it in an elementary school or at a college, students learn that there are three fundamental rock types: sedimentary, igneous, and metamorphic rocks. Sedimentary rocks are formed by the deposition of sediment by several processes, either by settling of sediment particles in a body of water, by chemical precipitation in water, or by transportation of the particles by water such as streams and rivers, or by wind (Figures 1-3). Maine Geological Survey Photo by Thomas K. Weddle K. Thomas by Photo Figure 1. Glacial marine sand beds with nearly parallel, horizontal layering, Buckfield, ME (entrenching tool for scale). Maine Geological Survey, Department of Agriculture, Conservation & Forestry 2 Sedimentary Structures in Metamorphic Rocks Maine Geological Survey Sedimentary Rocks Maine Geological Survey Photo by Thomas K. Weddle K. Thomas by Photo Figure 2. Fluvial trough cross bedding in slightly gravelly, coarse sand. The cross bed sets are incised into one another and highlighted by the darker colored layers (entrenching tool for scale), Buckfield, Maine. Maine Geological Survey, Department of Agriculture, Conservation & Forestry 3 Sedimentary Structures in Metamorphic Rocks Maine Geological Survey Sedimentary Rocks Maine Geological Survey Photo by Thomas K. Weddle K. Thomas by Photo Figure 3. Coarse cobble gravel in a glacial fluvial deposit, Kingfield, Maine (entrenching tool for scale). -
Lithostratigraphic Units
INTEGRATED STRATIGRAPHY Amalia Spina Amalia Spina, PhD. Office: Palazzina di Geologia, Second floor Tel. 0755852696 E-mail: [email protected] - Principles of stratigraphy - The time in stratigraphy; geological chronology (relative and absolute) the temporal sequence of events; standard global chronostratigraphical scale. Comparison between the stratigraphic scales in marine and continental successions. - Stratigraphic units standard (definition and principle): law of superimposition, principle of original horizontality, of lateral continuity and of biotic succession, the Stratigraphic Code. - The sedimentary cyclicity - Lithostratigraphy - Magnetostratigraphy - Biostratigraphy - Chemostratigraphy - Cronostratigraphy and geochronology - Astronomic cyclostratigraphy - Sequence stratigraphy - Palaeogeographic reconstructions. Prerequisites: In order to better comprehend the main topics of integrated stratigraphy, the students that follow this course must have: - knowledge of the fundamentals of geology; - knowledge of the sedimentary rocks (classification); - knowledge of the principle of stratigraphy; - knowledge of the principle of palaeontology; - knowledge of the principle of sedimentology; These preconditions are important for attending and not attending students. Written test: it consist of the solution of multiple choice test and graphic /practical exercises. The number of questions ranges between 15 and 30 on the basis of the difficulty.The test has a duration of no more than 80 minutes. The goal of the test is to verify the knowledge acquired on the course contents in order to ensure that the student learned the principles of integrated stratigraphy and its main applications. To complete the evaluation the test also consists on the discussion of a case study proposed by the Professor carried out individually or in small groups (max three students).It consists to discuss the stratigraphic features of a certain geological area and the implications for the subsurface hydrocarbon exploitation. -
The Old Red Sandstone of Britain and Ireland – a Review
The Old Red Sandstone of Britain and Ireland – a review RS Kendall British Geological Survey - Cardiff University, Main Building, Park Place, Cardiff. CF10 3AT. [email protected] Abstract The Old Red Sandstone (ORS) is an informal term which is given to continental, predominantly siliclastic, strata of late Silurian to early Carboniferous age which were deposited across the continent of Laurussia at sub-tropic to tropical latitudes. The coincidental development of land plants had a major impact on the atmosphere and global climate by lowering atmospheric carbon dioxide levels, which profoundly affected the style of alluvial sedimentation during this interval, by stabilising flood plains and facilitating the development of soils. The ORS also provides examples of syn- to post- orogenic deposition related to the Caledonian Orogeny, which was affected by synchronous tectonism and volcanism. The influence of Variscan tectonics on basin deformation and tectonism are also evident in the ORS sequence. In October 2014, a symposium was held, organised by the South Wales Geologists’ Association, entitled The Old Red Sandstone: is it Old, is it Red and is it all Sandstone? The event consisted of talks and posters on topics associated with the Old Red Sandstone deposits, principally of Wales and the Welsh Borders and the Scottish Borders in the UK, and included a series of field trips. Seven of the speakers have contributed manuscripts which are presented in this volume. These include papers discussing fossil fish and plant assemblages, the Fforest Fawr Geopark, Old Red Sandstone building stones, and soft sediment deformation. A brief report on the event and acknowledgements is also included. -
1 Structural Geology
Structural Geology – Laboratory 9 _____________________ (Name) Geologic maps show the distribution of different types of structures and rock stratigraphic units generally on a topographic base such as a quadrangle map. Key structures that are commonly shown include (1) bedding attitudes, (2) anticlines, (3) synclines, and (4) faults. A bedding attitude is defined as the strike and dip of a bed. Strike is the direction of a line produced by the intersection of an imaginary horizontal plane with an inclined bed. From previous laboratories you should know that based on the Principle of Original Horizontality sedimentary beds are originally deposited as a series of horizontal layers one on top of another. Such beds would have an infinite number of strike lines as the intersection of an imaginary horizontal plane with a horizontal bed is an infinite number of lines oriented from 0o to 360o (Figure 1). 1 In contrast, if a bed is inclined relative to the horizontal, then its intersection with an imaginary horizontal plane produces one and only one line (Figure 2). The direction of this line is the strike of the bed. 2 Dip is the angle between the imaginary horizontal plane and the inclined bed measured in a plane oriented at 90o to the strike line (Figure 3). In all of the above illustrations strike and dip is defined for an inclined layer such as a bed or lamination or rock stratigraphic unit (e.g., a member or formation). However, the orientation of any planar surface can be expressed by its strike and dip. For example, the orientation of a fault or foliation surface is commonly given as its strike and dip. -
Triassic and Jurassic Formations of the Newark Basin
TRIASSIC AND JURASSIC FORMATIONS OF THE NEWARK BASIN PAUL E. OLSEN Bingham Laboratories, Department of Biology, Yale University, New Haven, Connecticut Abstract Newark Supergroup deposits of the Newark Basin 1946), makes this deposit ideal for studying time-facies (New York, New Jersey and Pennsylvania) are divided relationships and evolutionary phenomena. These into nine formations called (from bottom up): Stockton recent discoveries have focused new interest on Newark Formation (maximum 1800 m); Lockatong Formation strata. (maximum 1150 m); Passaic Formation (maximum 6000 m); Orange Mountain Basalt (maximum 200 m); The Newark Basin (Fig. 1 and 2) is the largest of the Feltville Formation (maximum 600 m); Preakness exposed divisions of the Newark Supergroup, covering Basalt (maximum + 300 m); Towaco Formation (max- about 7770 km2 and stretching 220 km along its long imum 340 m); Hook Mountain Basalt (maximum 110 axis. The basin contains the thickest sedimentary se- m); and Boonton Formation (maximum + 500 m). Each quence of any exposed Newark Supergroup basin and formation is characterized by its own suite of rock correspondingly covers the greatest continuous amount - types, the differences being especially obvious in the of time. Thus, the Newark Basin occupies a central posi- number, thickness, and nature of their gray and black tion in the study of the Newark Supergroup as a whole. sedimentary cycles (or lack thereof). In well over a century of study the strata of Newark Fossils are abundant in the sedimentary formations of Basin have received a relatively large amount of atten- the Newark Basin and provide a means of correlating tion. By 1840, the basic map relations were worked out the sequence with other early Mesozoic areas. -
The Geology and Landscape of Moray
THE GEOLOGY AND LANDSCAPE OF MORAY Cornelius Gillen SOLID GEOLOGY Introduction The geology of Moray consists of an ancient basement of metamorphic rocks, the Moine Schist and Dalradian Schist, intruded by a series of granitic igneous rocks belonging to the Caledonian episode of mountain building, then uni:;onformably overlain by Old Red Sandstone sediments of the Devonian Period. Younger sediments, Permo-Triassic and Jurassic, are found along the coast, with Cretaceous rocks found only as ice-carried boulders. The main structure-forming event to affect the area was the Caledonian Orogeny, around 500 million years ago, which caused folding and meta morphism of the older rocks. Molten granite magma was forced into these folded basement rocks and contributed to the elevation of the area as part of the Grampian mountains - a component of the Caledonian fold mountain chain which stretches from northern Norway through Shetland, then on via Scotland to Ireland and Wales. The last event in the Caledonian Orogeny was the formation of a fault system that includes the Great Glen Fault which runs parallel to the coastline of Cromarty and continues seaward into the Moray Firth. Moine rocks In Moray, the oldest rocks are referred to as the Moine Schists, which form the high ground in the south and west of the district. This group of crystalline rocks forming the basement is made of quartzite, schist and gneiss. Originally the rocks were laid down as sandy, pebbly or gritty sediments with thin muds and shales, probably in shallow water, carried down by rivers and deposited in a shallow sea.