HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Services Similar articles in this journal Similar articles in Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (1) Citing Articles via Google Scholar Google Scholar Articles by Hibbard, J. P. Articles by Rankin, D. W. Search for Related Content Articles by Hibbard, J. P. Articles by Rankin, D. W. GeoRef GeoRef Citation

A comparative analysis of pre-Silurian crustal building blocks of the northern and the southern Appalachian orogen

^* Department of Marine, Earth and Atmospheric Sciences, North Carolina State University, Raleigh, North Carolina 27695 USA; jim_hibbard{at}ncsu.edu
^** Geological Survey of Canada, 101-605 Robson Street, Vancouver, British Columbia V6B 5J3 Canada
^*** US Geological Survey, National Center, Mail Stop 926A, Reston, Virginia 20192 USA

The New York promontory serves as the divide between the northern and southern segments of the Appalachian orogen. Antiquated subdivisions, distinct for each segment, implied that they had lithotectonic histories that were independent of each other. Using new lithotectonic subdivisions we compare first order features of the pre-Silurian orogenic ’building blocks’ in order to test the validity of the implication of independent lithotectonic histories for the two segments.

Three lithotectonic divisions, termed here the Laurentian, Iapetan, and the peri-Gondwanan realms, characterize the entire orogen. The Laurentian realm, composed of native North American rocks, is remarkably uniform for the length of the orogen. It records the multistage Neoproterozoic-early Paleozoic rift-drift history of the Appalachian passive margin, formation of a Taconic Seaway, and the ultimate demise of both in the Middle Ordovician. The Iapetan realm encompasses mainly oceanic and magmatic arc tracts that once lay within the Iapetus Ocean, between Laurentia and Gondwana. In the northern segment, the realm is divisible on the basis of stratigraphy and faunal provinciality into peri-Laurentian and peri-Gondwanan tracts that were amalgamated in the Late Ordovician. South of New York, stratigraphic and faunal controls decrease markedly; rock associations are not inconsistent with those of the northern Appalachians, although second-order differences exist. Exposed exotic crustal blocks of the peri-Gondwanan realm include Ganderia, Avalonia, and Meguma in the north, and Carolinia in the south. Carolinia most closely resembles Ganderia, both in early evolution and Late Ordovician-Silurian docking to Laurentia.

Our comparison indicates that, to a first order, the pre-Silurian Appalachian orogen developed uniformly, starting with complex rifting and a subsequent drift phase to form the Appalachian margin, followed by the consolidation of Iapetan components and ending with accretion of the peri-Gonwanan Ganderia and Carolinia. This deduction implies that any first-order differences between northern and southern segments post-date Late Ordovician consolidation of a large portion of the orogen.

This article has been cited by other articles:

				W. R. Dickinson and G. E. Gehrels U-Pb ages of detrital zircons in Jurassic eolian and associated sandstones of the Colorado Plateau: Evidence for transcontinental dispersal and intraregional recycling of sediment Geological Society of America Bulletin, March 1, 2009; 121(3-4): 408 - 433. [Abstract] [Full Text] [PDF]

				E.A. Konstantinovskaya, D. Rodriguez, D. Kirkwood, L.B. Harris, and R. Theriault Effects of Basement Structure, Sedimentation and Erosion on Thrust Wedge Geometry: An Example from the Quebec Appalachians and Analogue Models Bulletin of Canadian Petroleum Geology, March 1, 2009; 57(1): 34 - 62. [Abstract] [Full Text] [PDF]

				C. R. van Staal, J. B. Whalen, P. Valverde-Vaquero, A. Zagorevski, and N. Rogers Pre-Carboniferous, episodic accretion-related, orogenesis along the Laurentian margin of the northern Appalachians Geological Society, London, Special Publications, January 1, 2009; 327(1): 271 - 316. [Abstract] [Full Text] [PDF]

				D. Corrigan, S. Pehrsson, N. Wodicka, and E. de Kemp The Palaeoproterozoic Trans-Hudson Orogen: a prototype of modern accretionary processes Geological Society, London, Special Publications, January 1, 2009; 327(1): 457 - 479. [Abstract] [Full Text] [PDF]

				K. J. Schulz, D. B. Stewart, R. D. Tucker, J. C. Pollock, and R. A. Ayuso The Ellsworth terrane, coastal Maine: Geochronology, geochemistry, and Nd-Pb isotopic composition--Implications for the rifting of Ganderia Geological Society of America Bulletin, September 1, 2008; 120(9-10): 1134 - 1158. [Abstract] [Full Text] [PDF]

				C. G. Barnes, C. D. Frost, A. S. Yoshinobu, K. McArthur, M. A. Barnes, C. M. Allen, O. Nordgulen, and T. Prestvik Timing of sedimentation, metamorphism, and plutonism in the Helgeland Nappe Complex, north-central Norwegian Caledonides Geosphere, December 1, 2007; 3(6): 683 - 703. [Abstract] [Full Text] [PDF]