DOCSLIB.ORG

Thrust and Strike-Slip Faults Near Jackman, Maine

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Thrust and Strike-Slip Faults Near Jackman, Maine Maine Geological Survey Studies in Maine Geology: Volume 2 1989 Thrust and Strike-slip Faults near Jackman, Maine Robert G. Marvinney Maine Geological Survey State House Station 22 Augusta, Maine 04333 ABSTRACT The Marie Petuche fault, exposed at the international border station north of Jackman, Maine, is interpreted as a northwest-directed thrust. Evidence for this conclusion includes repetition of section, overturning of beds in the footwall, coincidence of a zone of kink folds, and outcrops which show southeast-dipping shear surfaces and fractures parallel to bedding and cleavage. This fault extends at least 25 km to the northeast. The Thrasher Peaks fault is a major fault which extends for nearly 200 km from northern New Hampshire into western Maine. Along most of its length the fault strikes northeast-southwest and has a vertical sense of displace­ ment. Outcrops of the fault northeast of Jackman indicate that the primary displacement on this east-west striking segment of the fault is right-lateral strike-slip. A fault gouge which contains cataclastically deformed clasts of Attean pluton in a slate matrix and kinematic indicators ornamenting shear surfaces are the primary evidence for this interpretation. The minimum demonstrated displacement is 10 km. This fault was probably active through much of the Acadian orogeny. The association of thrust and strike-slip faults is interpreted as a positive flower structure related to two factors: the curvilinear nature of the strike-slip fault and its unusual east-west strike in this region. The implications of this interpretation are that the overall displacement on the length of the Thrasher Peaks fault has been oblique and that the fault may continue for a considerable distance to the northeast. Possible candidates for the continuation of the fault toward the northeast are the suite of reverse faults in the Caucomgomoc Lake area. INTRODUCTION Since detailed bedrock investigations were first conducted Baudette ( 1972) recognized a zone of cataclasis representing in northwestern Maine during the 50's and 60's, the area which unknown translation in the northern part of the Attean pluton. In includes the junction of three major tectono-stratigraphic fea­ his investigations of the zone, Westerman (1979, 1980) proposed tures, the Connecticut Valley - Gaspe and the Moose River a normal fault dipping steeply to the northwest. Boone et al. synclinoria, and the Boundary Mountains anticlinorium (Fig. I), (1970) and Boone ( 1978, 1980) suggested that the fault zone is has been recognized as a broad, structurally complex zone of a series of northwest-dipping thrust faults. significance (see Boone et al., 1970; Albee and Boudette, 1972). The objectives of this paper are to present field evidence Recent investigations have concentrated in particular on the fault bearing on the nature of this structurally complex zone, to which bounds the Chain Lakes massif on its northwest side, consider structural associations within it, and finally to propose referred to as the Thrasher Peaks fault. a structural model for the region. This paper will consider two Interpretations of the nature of the Thrasher Peaks fault have faults within the broader zone. The first, the Marie Petuche fault, been nearly as numerous as the number of investigators owing is a zone of thrust faulting which includes a number of imbrica­ to paucity of outcrop and difficulty of access. Albee and tions. The second, the Thrasher Peaks fault, is interpreted to be 173 R. G. Marvinney OS Siluro-Devonian units, undifferentiated SO Ordovician-Silurian units, undifferentiated 70° 0£ Cambro·Ordovician units, undifferentiated I Oat Attean pluton p€cl Chain Lakes massif ~Ordovician plutons c:.,~;Joevonian plutons 7 t 0 TPF Thrasher Peaks fault 46°-r MPF Marie Petuche fault MNF Monroe fault DPF Deer Pond fault -fault --- contact OS \ \ ) .I I ( 452.....'..... -t-45° 70° 001•a•cm••10 miles o c:o:mm 1 O kilometers Figure I. Generalized bedrock geologic outline map of western Maine and northern New Hampshire (modified from Moench, 1984). of oblique movement along its entire length, but to be primarily suite (Baudette, 1982), and an Upper Cambrian(?) melange and a right-lateral, strike-slip fault along the segment studied in overlying Cambrian(?) and Lower Ordovician flysch carapace Maine (Fig. l). (Boone et al., 1984). Intruding the older rocks of the an­ ticlinorium is the Ordovician Attean pluton (443 Ma; Lyons et REGIONAL SETTING al., 1986), a mottled pink and green porphyritic quartz mon­ zonite. With the exception of this pluton, all of the rocks of the Of the three tectono-stratigraphic features in the region, the anticlinorium are deformed. Recent work (Boone and Baudette, Boundary Mountains anticlinorium exposes the oldest rocks. 1989; Boone, this volume) suggests that the deformation was These include the Middle Proterozoic Chain Lakes massif, the part of the mid-Cambrian to Early Ordovician Penobscottian Boil Mountain Complex, interpreted as a Cambrian(?) ophiolite orogeny. 174 Thrust and strike-slip faults near Jackman, Maine The Moose River and Connecticut Val ley - Gaspe fault. On the southeast side, beds in the Frontenac Formation synclinoria contain primarily Silurian and Devonian face to the southeast; lower stratigraphic levels are encountered metasedimentary and metavolcanic rocks in Maine although as the fault is approached. The frequency of interbedded slate toward the southwest in Vermont apparently older rocks are increases gradually toward the southeast as the contact with the exposed in the latter (Bothner and Berry, 1985). Most folding Ironbound Mountain Formation is approached. On the and faulting in the synclinoria can be related to the Acadian northwest side of the fault, beds face mostly northwestward. The orogeny. The metasedimentary units within the synclinoria of bedding style and frequency of interbedded slate on the most importance to this study are: the Frontenac Formation, a northwest side are similar to that of the transition zone with the thjck sequence of interbedded wacke and slate, and mafic vol­ Ironbound Mountain Formation encountered well to the canic rocks (Canada Falls Member) of probable Silurian age southeast. (Marvinney, 1986); the Upper Silurian or Lower Devonian Iron­ Second, the orientation and style of structural features chan­ bound Mountain Formation, a dark gray mudstone- and ges across the zone. On the southeast side, asymmetrical minor siltstone-slate unit (Marvinney, 1986); and the Lower Devonian folds are numerous, tight to isoclinal, and verge to the northwest. Northeast Carry Formation, a dark gray siltstone-slate and On the northwest side, minor folds are less numerous, open, and metasandstone unit. The last two formations are constituents of most often neutral in vergence. When interpreted as parasitic the recently defined Seboomook Group (cf. Pollock, 1987). The folds to a major structure and when considering the repetition of Frontenac and lronbound Mountain Formations are exposed in Devonian units on the northwest and southeast sides of the field a broad anticline along the southeast margin of the Connecticut area (Fig. 2), the northwest vergence of the minor folds on the Valley - Gaspe syncl inorium which has been sliced by northwest­ southeast initially seemed to indicate that this area was within directed thrust faults including the Marie Petuche fault (Fig. I). the southeast limb of a major northeast-trending anticline. The These uruts are of importance in establishing translations on each abruptness of change in style and vergence of minor folds across of the faults. a narrow zone, however, suggests that the minor folds are related The metasedimentary units present a particular difficulty to to a fault. The change in vergence is also important in estab­ structural interpretation in that they lack distinct, regionally lishing the translation on the fault. extensive, stratigraphic sequences. This is especially true of the Third, a narrow zone of kink folds, perhaps several hundred Frontenac Formation which contains packages of coarse­ meters wide, exists along the southeast side of the fault zone. grained, proximal turbidites (Marvinney, 1986) which vary in The kink folds (definition of Hobbs et al., I 976) are upright, stratigraphic position and tend to be laterally discontinuous. tight, have amplitudes and wavelengths of a few to tens of Only a general trend of upward-increasing frequency and thick­ centimeters, and have northeast-trending axes. They generally ness of interbedded slate has been recognized (Marvinney, occur in sections where the interbedded slate is thick. An impor­ l 986). Due to the lack of stratigraphic markers, the regional tant feature in many parts of the kink zone are near-vertical, thin structural interpretation draws heavily from analysis of cleavage, pseudobeds which result from the redistribution of quartz from minor structures, and, in the case of faults, several outcrops the kink fold limbs into their hinge zones. This suggests that the which show their nature, rather than on map patterns of axis of maximum shortening was nearly horizontal during stratigraphic units. development of the kink folds. Folds of this form commonly occur with their axial planes perpendicular to the axis of maxi­ THRUST FAULTS mum compression as a consequence of 50% shortening in fine grained rocks (Paterson and Weiss, 1966). Marie Petuche Fault In several areas the Marie Petuche fault is exposed, but nowhere as well as in the roadcuts at the international border Several thrust faults are mapped in the study area, the station on U.S. Route 201, shown in Figure 3 (#1, Fig. 2). Here longest of which is the Marie Petuche fault (Fig. 2). This fault the fault cuts thick wackes and interbedded slate of the Frontenac extends from the international border station on U.S. 20 I - Formation in a zone of nearly continuous exposure 160 meters Quebec 173 (#I on Fig. 2) northeastward along the international wide. Through much of the roadcut, especially the western end, border and the southeast side of Green Mountain (#2 on Fig.
Load more

Recommended publications
  • Linking Megathrust Earthquakes to Brittle Deformation in a Fossil Accretionary Complex
    ARTICLE Received 9 Dec 2014 | Accepted 13 May 2015 | Published 24 Jun 2015 DOI: 10.1038/ncomms8504 OPEN Linking megathrust earthquakes to brittle deformation in a fossil accretionary complex Armin Dielforder1, Hauke Vollstaedt1,2, Torsten Vennemann3, Alfons Berger1 & Marco Herwegh1 Seismological data from recent subduction earthquakes suggest that megathrust earthquakes induce transient stress changes in the upper plate that shift accretionary wedges into an unstable state. These stress changes have, however, never been linked to geological structures preserved in fossil accretionary complexes. The importance of coseismically induced wedge failure has therefore remained largely elusive. Here we show that brittle faulting and vein formation in the palaeo-accretionary complex of the European Alps record stress changes generated by subduction-related earthquakes. Early veins formed at shallow levels by bedding-parallel shear during coseismic compression of the outer wedge. In contrast, subsequent vein formation occurred by normal faulting and extensional fracturing at deeper levels in response to coseismic extension of the inner wedge. Our study demonstrates how mineral veins can be used to reveal the dynamics of outer and inner wedges, which respond in opposite ways to megathrust earthquakes by compressional and extensional faulting, respectively. 1 Institute of Geological Sciences, University of Bern, Baltzerstrasse 1 þ 3, Bern CH-3012, Switzerland. 2 Center for Space and Habitability, University of Bern, Sidlerstrasse 5, Bern CH-3012, Switzerland. 3 Institute of Earth Surface Dynamics, University of Lausanne, Geˆopolis 4634, Lausanne CH-1015, Switzerland. Correspondence and requests for materials should be addressed to A.D. (email: [email protected]). NATURE COMMUNICATIONS | 6:7504 | DOI: 10.1038/ncomms8504 | www.nature.com/naturecommunications 1 & 2015 Macmillan Publishers Limited.
    [Show full text]
  • Tectonics of the Musandam Peninsula and Northern Oman Mountains: from Ophiolite Obduction to Continental Collision
    GeoArabia, 2014, v. 19, no. 2, p. 135-174 Gulf PetroLink, Bahrain Tectonics of the Musandam Peninsula and northern Oman Mountains: From ophiolite obduction to continental collision Michael P. Searle, Alan G. Cherry, Mohammed Y. Ali and David J.W. Cooper ABSTRACT The tectonics of the Musandam Peninsula in northern Oman shows a transition between the Late Cretaceous ophiolite emplacement related tectonics recorded along the Oman Mountains and Dibba Zone to the SE and the Late Cenozoic continent-continent collision tectonics along the Zagros Mountains in Iran to the northwest. Three stages in the continental collision process have been recognized. Stage one involves the emplacement of the Semail Ophiolite from NE to SW onto the Mid-Permian–Mesozoic passive continental margin of Arabia. The Semail Ophiolite shows a lower ocean ridge axis suite of gabbros, tonalites, trondhjemites and lavas (Geotimes V1 unit) dated by U-Pb zircon between 96.4–95.4 Ma overlain by a post-ridge suite including island-arc related volcanics including boninites formed between 95.4–94.7 Ma (Lasail, V2 unit). The ophiolite obduction process began at 96 Ma with subduction of Triassic–Jurassic oceanic crust to depths of > 40 km to form the amphibolite/granulite facies metamorphic sole along an ENE- dipping subduction zone. U-Pb ages of partial melts in the sole amphibolites (95.6– 94.5 Ma) overlap precisely in age with the ophiolite crustal sequence, implying that subduction was occurring at the same time as the ophiolite was forming. The ophiolite, together with the underlying Haybi and Hawasina thrust sheets, were thrust southwest on top of the Permian–Mesozoic shelf carbonate sequence during the Late Cenomanian–Campanian.
    [Show full text]
  • Describe the Geometry of a Fault (1) Orientation of the Plane (Strike and Dip) (2) Slip Vector
    Learning goals - January 16, 2012 You will understand how to: Describe the geometry of a fault (1) orientation of the plane (strike and dip) (2) slip vector Understand concept of slip rate and how it is estimated Describe faults (the above plus some jargon weʼll need) Categories of Faults (EOSC 110 version) “Normal” fault “Thrust” or “reverse” fault “Strike-slip” or “transform” faults Two kinds of strike-slip faults Right-lateral Left-lateral (dextral) (sinistral) Stand with your feet on either side of the fault. Which side comes toward you when the fault slips? Another way to tell: stand on one side of the fault looking toward it. Which way does the block on the other side move? Right-lateral Left-lateral (dextral) (sinistral) 1992 M 7.4 Landers, California Earthquake rupture (SCEC) Describing the fault geometry: fault plane orientation How do you usually describe a plane (with lines)? In geology, we choose these two lines to be: • strike • dip strike dip • strike is the azimuth of the line where the fault plane intersects the horizontal plane. Measured clockwise from N. • dip is the angle with respect to the horizontal of the line of steepest descent (perpendic. to strike) (a ball would roll down it). strike “60°” dip “30° (to the SE)” Profile view, as often shown on block diagrams strike 30° “hanging wall” “footwall” 0° N Map view Profile view 90° W E 270° S 180° Strike? Dip? 45° 45° Map view Profile view Strike? Dip? 0° 135° Indicating direction of slip quantitatively: the slip vector footwall • let’s define the slip direction (vector)
    [Show full text]
  • Geotectonic Model of the Alpine Development of Lakavica Graben in the Eastern Part of the Vardar Zone in the Republic of Macedonia
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by UGD Academic Repository Geologica Macedonica, Vol. 27, No. 1, pp. 87–93 (2013) GEOME 2 ISSN 0352 – 1206 Manuscript received: May 17, 2013 UDC: 551.245.03(497.71/.73) Accepted: October 25, 2013 Original scientific paper GEOTECTONIC MODEL OF THE ALPINE DEVELOPMENT OF LAKAVICA GRABEN IN THE EASTERN PART OF THE VARDAR ZONE IN THE REPUBLIC OF MACEDONIA Goše Petrov, Violeta Stojanova, Gorgi Dimov Faculty of Natural and Technical Sciences, “Goce Delčev” University, P.O.Box 201, MK 2000 Štip, Republic of Macedonia [email protected]//[email protected] A b s t r a c t: Lakavica graben is located in the eastern subzone of the Vardar zone, which during the Alpine orogenesis was covered with very complex processes of tectogenesis. On the area of about 200 km2, in the Lakavica graben, are present geological units from the oldest geological periods (Precam- brian) to the youngest (Neogene and Quaternary). Tectonic structure, or rupture tectonic, is very intense developed and gives possibility for analysis of the geotectonic processes in the Alpine orogen phase. This paper presents the possible model for geotectonic processes in the Lakavica graben, according to which can be generalized geotectonic processes in the Vardar zone during the Alpine orogeny. Key words: Lakavica graben; geotectonic model; Alpine orogeny; Vardar zone INTRODUCTION Vardar zone as a tectonic unit, for the first niki Gulf (Greece), than bent eastward and crosses time, is separated and showed on the "Geological- the ophiolite zone Izmir–Ankara (Turkey).
    [Show full text]
  • Along Strike Variability of Thrust-Fault Vergence
    Brigham Young University BYU ScholarsArchive Theses and Dissertations 2014-06-11 Along Strike Variability of Thrust-Fault Vergence Scott Royal Greenhalgh Brigham Young University - Provo Follow this and additional works at: https://scholarsarchive.byu.edu/etd Part of the Geology Commons BYU ScholarsArchive Citation Greenhalgh, Scott Royal, "Along Strike Variability of Thrust-Fault Vergence" (2014). Theses and Dissertations. 4095. https://scholarsarchive.byu.edu/etd/4095 This Thesis is brought to you for free and open access by BYU ScholarsArchive. It has been accepted for inclusion in Theses and Dissertations by an authorized administrator of BYU ScholarsArchive. For more information, please contact [email protected], [email protected]. Along Strike Variability of Thrust-Fault Vergence Scott R. Greenhalgh A thesis submitted to the faculty of Brigham Young University in partial fulfillment of the requirements for the degree of Master of Science John H. McBride, Chair Brooks B. Britt Bart J. Kowallis John M. Bartley Department of Geological Sciences Brigham Young University April 2014 Copyright © 2014 Scott R. Greenhalgh All Rights Reserved ABSTRACT Along Strike Variability of Thrust-Fault Vergence Scott R. Greenhalgh Department of Geological Sciences, BYU Master of Science The kinematic evolution and along-strike variation in contractional deformation in over- thrust belts are poorly understood, especially in three dimensions. The Sevier-age Cordilleran overthrust belt of southwestern Wyoming, with its abundance of subsurface data, provides an ideal laboratory to study how this deformation varies along the strike of the belt. We have per- formed a detailed structural interpretation of dual vergent thrusts based on a 3D seismic survey along the Wyoming salient of the Cordilleran overthrust belt (Big Piney-LaBarge field).
    [Show full text]
  • From Orogeny to Rifting: When and How Does Rifting Begin? Insights from the Norwegian ‘Reactivation Phase’
    EGU21-469 https://doi.org/10.5194/egusphere-egu21-469 EGU General Assembly 2021 © Author(s) 2021. This work is distributed under the Creative Commons Attribution 4.0 License. From orogeny to rifting: when and how does rifting begin? Insights from the Norwegian ‘reactivation phase’. Gwenn Peron-Pinvidic1,2, Per Terje Osmundsen2, Loic Fourel1, and Susanne Buiter3 1NGU - Geological Survey of Norway, 7040 Trondheim, Norway 2NTNU - Norwegian University of Science and Technology, 7491 Trondheim, Norway 3Tectonics and Geodynamics, RWTH Aachen University, 52064 Aachen, Germany Following the Wilson Cycle theory, most rifts and rifted margins around the world developed on former orogenic suture zones (Wilson, 1966). This implies that the pre-rift lithospheric configuration is heterogeneous in most cases. However, for convenience and lack of robust information, most models envisage the onset of rifting based on a homogeneously layered lithosphere (e.g. Lavier and Manatschal, 2006). In the last decade this has seen a change, thanks to the increased academic access to high-resolution, deeply imaging seismic datasets, and numerous studies have focused on the impact of inheritance on the architecture of rifts and rifted margins. The pre-rift tectonic history has often been shown as strongly influencing the subsequent rift phases (e.g. the North Sea case - Phillips et al., 2016). In the case of rifts developing on former orogens, one important question relates to the distinction between extensional structures formed during the orogenic collapse and the ones related to the proper onset of rifting. The collapse deformation is generally associated with polarity reversal along orogenic thrusts, ductile to brittle deformation and important crustal thinning with exhumation of deeply buried rocks (Andersen et al., 1994; Fossen, 2000).
    [Show full text]
  • Development of the Rocky Mountain Foreland Basin: Combined Structural
    University of Montana ScholarWorks at University of Montana Graduate Student Theses, Dissertations, & Professional Papers Graduate School 2007 DEVELOPMENT OF THE ROCKY MOUNTAIN FORELAND BASIN: COMBINED STRUCTURAL, MINERALOGICAL, AND GEOCHEMICAL ANALYSIS OF BASIN EVOLUTION, ROCKY MOUNTAIN THRUST FRONT, NORTHWEST MONTANA Emily Geraghty Ward The University of Montana Follow this and additional works at: https://scholarworks.umt.edu/etd Let us know how access to this document benefits ou.y Recommended Citation Ward, Emily Geraghty, "DEVELOPMENT OF THE ROCKY MOUNTAIN FORELAND BASIN: COMBINED STRUCTURAL, MINERALOGICAL, AND GEOCHEMICAL ANALYSIS OF BASIN EVOLUTION, ROCKY MOUNTAIN THRUST FRONT, NORTHWEST MONTANA" (2007). Graduate Student Theses, Dissertations, & Professional Papers. 1234. https://scholarworks.umt.edu/etd/1234 This Dissertation is brought to you for free and open access by the Graduate School at ScholarWorks at University of Montana. It has been accepted for inclusion in Graduate Student Theses, Dissertations, & Professional Papers by an authorized administrator of ScholarWorks at University of Montana. For more information, please contact [email protected]. DEVELOPMENT OF THE ROCKY MOUNTAIN FORELAND BASIN: COMBINED STRUCTURAL, MINERALOGICAL, AND GEOCHEMICAL ANALYSIS OF BASIN EVOLUTION ROCKY MOUNTAIN THRUST FRONT, NORTHWEST MONTANA By Emily M. Geraghty Ward B.A., Whitman College, Walla Walla, WA, 1999 M.S., Washington State University, Pullman, WA, 2002 Dissertation presented in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Geology The University of Montana Missoula, MT Spring 2007 Approved by: Dr. David A. Strobel, Dean Graduate School James W. Sears, Chair Department of Geosciences Julia A. Baldwin Department of Geosciences Marc S. Hendrix Department of Geosciences Steven D.
    [Show full text]
  • THE GROWTH of SHEEP MOUNTAIN ANTICLINE: COMPARISON of FIELD DATA and NUMERICAL MODELS Nicolas Bellahsen and Patricia E
    THE GROWTH OF SHEEP MOUNTAIN ANTICLINE: COMPARISON OF FIELD DATA AND NUMERICAL MODELS Nicolas Bellahsen and Patricia E. Fiore Department of Geological and Environmental Sciences, Stanford University, Stanford, CA 94305 e-mail: [email protected] be explained by this deformed basement cover interface Abstract and does not require that the underlying fault to be listric. In his kinematic model of a basement involved We study the vertical, compression parallel joint compressive structure, Narr (1994) assumes that the set that formed at Sheep Mountain Anticline during the basement can undergo significant deformations. Casas early Laramide orogeny, prior to the associated folding et al. (2003), in their analysis of field data, show that a event. Field data indicate that this joint set has a basement thrust sheet can undergo a significant heterogeneous distribution over the fold. It is much less penetrative deformation, as it passes over a flat-ramp numerous in the forelimb than in the hinge and geometry (fault-bend fold). Bump (2003) also discussed backlimb, and in fact is absent in many of the forelimb how, in several cases, the basement rocks must be field measurement sites. Using 3D elastic numerical deformed by the fault-propagation fold process. models, we show that early slip along an underlying It is noteworthy that basement deformation often is thrust fault would have locally perturbed the neglected in kinematic (Erslev, 1991; McConnell, surrounding stress field, inducing a compression that 1994), analogue (Sanford, 1959; Friedman et al., 1980), would inhibit joint formation above the fault tip. and numerical models. This can be attributed partially Relating the absence of joints in the forelimb to this to the fact that an understanding of how internal stress perturbation, we are able to constrain the deformation is delocalized in the basement is lacking.
    [Show full text]
  • Pan-African Orogeny 1
    Encyclopedia 0f Geology (2004), vol. 1, Elsevier, Amsterdam AFRICA/Pan-African Orogeny 1 Contents Pan-African Orogeny North African Phanerozoic Rift Valley Within the Pan-African domains, two broad types of Pan-African Orogeny orogenic or mobile belts can be distinguished. One type consists predominantly of Neoproterozoic supracrustal and magmatic assemblages, many of juvenile (mantle- A Kröner, Universität Mainz, Mainz, Germany R J Stern, University of Texas-Dallas, Richardson derived) origin, with structural and metamorphic his- TX, USA tories that are similar to those in Phanerozoic collision and accretion belts. These belts expose upper to middle O 2005, Elsevier Ltd. All Rights Reserved. crustal levels and contain diagnostic features such as ophiolites, subduction- or collision-related granitoids, lntroduction island-arc or passive continental margin assemblages as well as exotic terranes that permit reconstruction of The term 'Pan-African' was coined by WQ Kennedy in their evolution in Phanerozoic-style plate tectonic scen- 1964 on the basis of an assessment of available Rb-Sr arios. Such belts include the Arabian-Nubian shield of and K-Ar ages in Africa. The Pan-African was inter- Arabia and north-east Africa (Figure 2), the Damara- preted as a tectono-thermal event, some 500 Ma ago, Kaoko-Gariep Belt and Lufilian Arc of south-central during which a number of mobile belts formed, sur- and south-western Africa, the West Congo Belt of rounding older cratons. The concept was then extended Angola and Congo Republic, the Trans-Sahara Belt of to the Gondwana continents (Figure 1) although West Africa, and the Rokelide and Mauretanian belts regional names were proposed such as Brasiliano along the western Part of the West African Craton for South America, Adelaidean for Australia, and (Figure 1).
    [Show full text]
  • Deepwater Fold-And-Thrust Belt Along New Caledonia's Western Margin
    Deepwater fold-and-thrust belt along New Caledonia’s western margin: relation to post-obduction vertical motions J. Collot, M. Patriat, S. Etienne, P. Rouillard, F. Soetaert, C Juan, B. Marcaillou, Giulia Palazzin, Camille Clerc, P. Maurizot, et al. To cite this version: J. Collot, M. Patriat, S. Etienne, P. Rouillard, F. Soetaert, et al.. Deepwater fold-and-thrust belt along New Caledonia’s western margin: relation to post-obduction vertical motions. Tectonics, American Geophysical Union (AGU), 2017, 36, pp.2108-2122. 10.1002/2017TC004542. insu-01614136 HAL Id: insu-01614136 https://hal-insu.archives-ouvertes.fr/insu-01614136 Submitted on 24 Oct 2017 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. PUBLICATIONS Tectonics RESEARCH ARTICLE Deepwater Fold-and-Thrust Belt Along New 10.1002/2017TC004542 Caledonia’s Western Margin: Relation Key Points: to Post-obduction Vertical Motions • New deepwater fold-and-thrust belt discovered off New Caledonia’s J. Collot1 , M. Patriat1,2 , S. Etienne1,3 , P. Rouillard1,3,4, F. Soetaert1,2, C. Juan1, western margin 5 6 7 1 1,3 1,3 1 • Origin of the deepwater B. Marcaillou , G. Palazzin , C.
    [Show full text]
  • The Penokean Orogeny in the Lake Superior Region Klaus J
    Precambrian Research 157 (2007) 4–25 The Penokean orogeny in the Lake Superior region Klaus J. Schulz ∗, William F. Cannon U.S. Geological Survey, 954 National Center, Reston, VA 20192, USA Received 16 March 2006; received in revised form 1 September 2006; accepted 5 February 2007 Abstract The Penokean orogeny began at about 1880 Ma when an oceanic arc, now the Pembine–Wausau terrane, collided with the southern margin of the Archean Superior craton marking the end of a period of south-directed subduction. The docking of the buoyant craton to the arc resulted in a subduction jump to the south and development of back-arc extension both in the initial arc and adjacent craton margin to the north. A belt of volcanogenic massive sulfide deposits formed in the extending back-arc rift within the arc. Synchronous extension and subsidence of the Superior craton resulted in a broad shallow sea characterized by volcanic grabens (Menominee Group in northern Michigan). The classic Lake Superior banded iron-formations, including those in the Marquette, Gogebic, Mesabi and Gunflint Iron Ranges, formed in that sea. The newly established subduction zone caused continued arc volcanism until about 1850 Ma when a fragment of Archean crust, now the basement of the Marshfield terrane, arrived at the subduction zone. The convergence of Archean blocks of the Superior and Marshfield cratons resulted in the major contractional phase of the Penokean orogeny. Rocks of the Pembine–Wausau arc were thrust northward onto the Superior craton causing subsidence of a foreland basin in which sedimentation began at about 1850 Ma in the south (Baraga Group rocks) and 1835 Ma in the north (Rove and Virginia Formations).
    [Show full text]
  • Collision Orogeny
    Downloaded from http://sp.lyellcollection.org/ by guest on October 6, 2021 PROCESSES OF COLLISION OROGENY Downloaded from http://sp.lyellcollection.org/ by guest on October 6, 2021 Downloaded from http://sp.lyellcollection.org/ by guest on October 6, 2021 Shortening of continental lithosphere: the neotectonics of Eastern Anatolia a young collision zone J.F. Dewey, M.R. Hempton, W.S.F. Kidd, F. Saroglu & A.M.C. ~eng6r SUMMARY: We use the tectonics of Eastern Anatolia to exemplify many of the different aspects of collision tectonics, namely the formation of plateaux, thrust belts, foreland flexures, widespread foreland/hinterland deformation zones and orogenic collapse/distension zones. Eastern Anatolia is a 2 km high plateau bounded to the S by the southward-verging Bitlis Thrust Zone and to the N by the Pontide/Minor Caucasus Zone. It has developed as the surface expression of a zone of progressively thickening crust beginning about 12 Ma in the medial Miocene and has resulted from the squeezing and shortening of Eastern Anatolia between the Arabian and European Plates following the Serravallian demise of the last oceanic or quasi- oceanic tract between Arabia and Eurasia. Thickening of the crust to about 52 km has been accompanied by major strike-slip faulting on the rightqateral N Anatolian Transform Fault (NATF) and the left-lateral E Anatolian Transform Fault (EATF) which approximately bound an Anatolian Wedge that is being driven westwards to override the oceanic lithosphere of the Mediterranean along subduction zones from Cephalonia to Crete, and Rhodes to Cyprus. This neotectonic regime began about 12 Ma in Late Serravallian times with uplift from wide- spread littoral/neritic marine conditions to open seasonal wooded savanna with coiluvial, fluvial and limnic environments, and the deposition of the thick Tortonian Kythrean Flysch in the Eastern Mediterranean.
    [Show full text]