Acadian orogeny

Last updated

The Acadian orogeny is a long-lasting mountain building event which began in the Middle Devonian, reaching a climax in the Late Devonian. [1] It was active for approximately 50 million years, beginning roughly around 375 million years ago (Ma), with deformational, plutonic, and metamorphic events extending into the early Mississippian. [2] The Acadian orogeny is the third of the four orogenies that formed the Appalachian Mountains and subsequent basin. The preceding orogenies consisted of the Grenville and Taconic orogenies, which followed a rift/drift stage in the Neoproterozoic. [3] The Acadian orogeny involved the collision of a series of Avalonian continental fragments with the Laurasian continent. Geographically, the Acadian orogeny extended from the Canadian Maritime provinces migrating in a southwesterly direction toward Alabama. [4] However, the northern Appalachian region, from New England northeastward into Gaspé region of Canada, was the most greatly affected region by the collision. [2]

Contents

It was roughly contemporaneous with the Bretonic phase of the Variscan orogeny of Laurussia, with metamorphic events in southwestern Texas and northern Mexico, and with the Antler orogeny of the Great Basin.

Paleogeographic reconstruction showing the Appalachian Basin area during the Middle Devonian period. Eastern North American Paleogeograpy Middle Devonian.png
Paleogeographic reconstruction showing the Appalachian Basin area during the Middle Devonian period.

Palaeogeography

During the time of the Acadian orogeny, Middle Devonian (385 Ma), the paleolatitude of the Laurentia was in the southern hemisphere near the equator, between 0° to 30°S latitude. [6] Laurentia did not change much with respect to paleolatitude during the Devonian. Gondwana, on the other hand, traveled a large distance, such that in the Ordovician the South Pole was located in northern Africa, where it then moved west of southern Chile during the Silurian, and moved back to central Africa during the Devonian. [7] However, more recent research, from Scotese & McKerrow, suggests that in Late Devonian, the South Pole was in north-central Argentina rather than northern Africa, which was supported with paleoclimatic evidence. [6] The paleolatitude of Gondwana during the Middle to Late Devonian resided around intermediate latitudes of about 50°S. [7]

The collision initiating the Acadian orogeny resulted in the closing of the southern Iapetus Ocean and the formation of a high mountain belt. [6] After the Acadian collision took place, Gondwana began to retreat from Laurentia with the newly accreted Avalonian terranes left behind. As Gondwana moved away, a new ocean opened up, the Rheic Ocean, during the Middle to Late Devonian, and subsequently its closure resulted in the formation of the Alleghanian orogeny. [7]

Laurentia

Laurentia is the North American paleocontinent, which also includes present day northwest Ireland, Scotland, Greenland, the north slope of Alaska, and the Chukotsk Peninsula of northeastern Russia. [6] During the Ordovician-Devonian time, Laurentia remained at the same paleolatitude, slightly south of the equator in the southern hemisphere, with relatively the same paleolongitude. [7] Major defining tectonic events include the Neoproterozoic rift sequence from the breakup of Grenville basement rocks, thermal subsidence related to the Early Cambrian to Middle Ordovician drift sequence during the opening of the Iapetus Ocean, the Appalachian accretionary events to the eastern continental margin, and the resulting foreland-basin and clastic wedges. [8]

Avalonian terranes

Avalonian terranes that constitute Avalonia are the following modern-day regions: northern France, Belgium (the Ardennes), England, Wales, southeastern Ireland, eastern Newfoundland, Nova Scotia, southern New Brunswick and some coastal parts of New England. The basement consisted of Late Precambrian age arc rocks and is believed to come from the margin of Gondwana, sometime in the Early Ordovician. [6] Avalonia rifted from Gondwana during the onset of igneous activity in the Ardennes, Wales, and southeast Ireland that consumed the Tornquist Sea oceanic crust. It drifted in a northerly direction and probably collided with Baltica in the Late Ordovician, and then with Laurentia in the Late Devonian. Evidence for this is consistent with paleomagnetic data which place Avalonia at a temperate latitude during the Ordovician and in a subtropical latitude during the Late Ordovician through the Devonian. [6]

Overview of events

The Acadian orogeny resulted from oblique convergence or major transcurrent movement along a large strike-slip fault which represents the zone of convergence between Laurussia/Laurentia and Avalon terranes. [4] One or more of the Avalonian terranes accreted with the eastern margin of Laurentia, most likely beginning in the late Early Devonian. [9]

The evidence for the Acadian orogeny is abundant and widespread in the northern Appalachians, recorded by the plutonism and the migration of the northern Appalachian deformation front toward the craton. In the central to southern Appalachians, evidence for the Acadian orogeny is poor and is found primarily in the plutonism of the Blue Ridge and metamorphism of the Cat Square terrane. [10]

The Acadian orogeny experienced at least three major phases of deformation, and in places, unconformities are recognized. [4] These phases are called tectophases and represent the sequence of collisions that occurred from the Avalonian terranes accreting to Laurentia. As a result of these tectophases, deltas developed on the adjacent parts of the stable craton, eastern margin of Laurentia. [11] These deltas are described as foreland-basin, delta-complex clastic wedges, which are responsible for the large volumes of sediment input into the Appalachian basin. [9]

Collision

The Appalachian Orogeny, a result of three separate continental collisions. USGS Appalachian orogeny.jpg
The Appalachian Orogeny, a result of three separate continental collisions. USGS

The collision of Avalonia with Laurentia initiated a sequence of events where the older rocks were subjected to deformation, plutonism, metamorphism, and uplift that occurred over a large area of eastern Laurentia. [12] During the course of the orogeny, new faults formed, while older faults were reactivated. [2] Acadian deformation and metamorphism were asymmetric across the strike of the orogen. The Acadian plutons intruded every belt, unlike the deformation/metamorphism, of Avalonia which did not undergo much of the alteration shown in other localities. [13] During the Middle Devonian, centers for volcanoes and uplift formed in the New England region and shed fine-grained clastic material into an inland seaway that covered a large part of southern and central Appalachia. Today, portions of the ancient Avalonia landmass occur in scattered outcrop belts along the eastern margin of North America. One belt occurs in Newfoundland; another forms the bedrock of much of the coastal region of New England from eastern Connecticut to northern Maine, where it is known as the Coastal Lithotectonic Block. [2]

The collision between Laurentia and Avalonian terranes is actually more complex than described above. The collision is broken into three or possibly four tectophases which represent a successive collision of the Avalonian terranes with eastern Laurentia. [4] [11]

Tectophases

Because major clastic wedges and basinal deposits are distributed in a southwestward progression, it is assumed they originated from areas near promontories, areas along the continental margin where deformation is concentrated. The earliest tectophase was located at the St. Lawrence promontory in northern New England and in the Canadian Maritime Provinces. [9] The St. Lawrence tectophase was active during the Early to Middle Devonian with intense transpressional deformation which formed a basin in the Gaspé Peninsula, northern New Brunswick, and northern New England. [11] Clastic wedges were present in this area, but the evidence for them has been mostly destroyed by succeeding tectonism. [9]

The second tectophase, during the Middle Devonian, represents the collision with the New York promontory. The southward migration of deformation reflected the third tectophase, which marks the collision of Avalon terranes with the Virginia promontory in the Middle to Late Devonian time. The effects of the New York and Virginia promontories together produced the Catskill Delta complex. [9]

As the migration of deformation continued southward along the fault zone, during the Early Mississippian time, the final collision occurred with the Alabama promontory . [11] Ettensohn refers to the fourth tectophase as the Mississippian tectophase of the Acadian orogeny, since it demonstrated an unusually long duration (Mississippian-Early Pennsylvanian). [9] Subsequently, the Pocono and equivalent clastic wedges essentially filled the epicontinental sea. The deposition of Middle Mississippian carbonates marks the end of the Acadian orogeny and Catskill Delta complex. [11]

Foreland basin

The Acadian foreland basin is a retroarc Peripheralvs.Retroarc.png
The Acadian foreland basin is a retroarc

Foreland basins are a product of tectonic deformational loading, or crustal thickening along the orogen, a consequence of overthrusting and folding. The Acadian foreland basin is categorized as a retroarc foreland basin, which occurs on the overriding continental lithosphere, adjacent to a foreland fold-thrust belt behind a continental margin arc. [4] The initial result of loading is a bulge move out and uplift of the foreland, which generates a localized unconformity. The distributions of unconformities display an asymmetric pattern in relation to the promontories. [14] Subsidence follows bulge movement and uplift and is produced on the cratonic side of the orogen due to regional isostatic adjustment to the load by the lithosphere. [4] Once thrust propagation declines, substantial relief and drainage nets have had time to develop, and the as a resulting coarser clastic sediment is eroded and transported to the foreland basin. [14]

The basement structures of the Appalachian foreland basin at the onset of the Acadian orogeny were reactivated during foreland lithospheric flexure. These structures affected the foreland basin evolution and sedimentation patterns, and the preexisting faults partitioned the basin into regions of fault-controlled uplift and depocenters. [15]

Delta complex

The Appalachian basin, during the Middle Devonian and Early Mississippian, is characterized by large volumes of deltaic sedimentary rocks that were deposited in the Acadian foreland basin as a response to the Acadian orogeny. These deposits extend from central New York and Pennsylvania westward to Ohio, and south along the Appalachian Mountains through Virginia and Tennessee to Alabama. The Acadian delta complex is categorized into two deltas, the Catskill Delta of Middle and Upper Devonian age, and the Price-Rockwell in the Pocono Mountains delta of Late Devonian and Early Mississippian age. [16] The Acadian delta complex is coupled to the four tectophases of the Acadian orogeny, both in terms of provenance and depositional settings. The relief resulting from the orogeny was the fundamental source of the delta sediments. [11]

The Catskill Delta complex consists of a coarsening upward sequence of rocks. Its thickness is greatest in eastern Pennsylvania and thins westward into Ohio. The Catskill paleogeography appears to consist of many small streams, which deposited their sedimentary load along a coastal alluvial plain that was hundreds of miles long. [16]

Generalized stratigraphic nomenclature for the Middle Devonian strata in the Appalachian Basin USGS 2006 1237 table2 Stratigraphy Middle Devonian.svg
Generalized stratigraphic nomenclature for the Middle Devonian strata in the Appalachian Basin

The Middle Devonian to Lower Mississippian siliciclastic strata, deposited by the Catskill Delta, includes black shale, gray shale, sandstone, red beds, and minor argillaceous limestone. The strata was deposited in a four-stage pattern that is observed in each tectophase. The formation of the foreland basin through rapid subsidence initiated transgressive sequences that deposited basinal black shales. After the black shales were deposited, the migration of deformation continued southward, and regression dominated, particularly on the east side of the basin. As collision intensified, subsidence in the foreland basin declined, and sedimentation was replaced by an influx of calcareous silty shales and carbonates. These deposits reflect small transgressive-regressive cycles in a delta-front and delta platform environments. The third stage is represented by regional uplift, which accompanied the collision of an Avalon terrane with a promontory, and subsequently, developed a regional disconformity. The fourth and final stage is represented by tectonic quiescence with a widespread carbonate deposition in a slowly transgressing sea. [11]

See also

Related Research Articles

<span class="mw-page-title-main">Laurasia</span> Northern landmass that formed part of the Pangaea supercontinent

Laurasia was the more northern of two large landmasses that formed part of the Pangaea supercontinent from around 335 to 175 million years ago (Mya), the other being Gondwana. It separated from Gondwana 215 to 175 Mya during the breakup of Pangaea, drifting farther north after the split and finally broke apart with the opening of the North Atlantic Ocean c. 56 Mya. The name is a portmanteau of Laurentia and Asia.

<span class="mw-page-title-main">Geology of the Appalachians</span> Geologic description of the Appalachian Mountains

The geology of the Appalachians dates back more than 1.2 billion years to the Mesoproterozoic era when two continental cratons collided to form the supercontinent Rodinia, 500 million years prior to the development of the range during the formation of Pangea. The rocks exposed in today's Appalachian Mountains reveal elongate belts of folded and thrust faulted marine sedimentary rocks, volcanic rocks, and slivers of ancient ocean floor—strong evidences that these rocks were deformed during plate collision. The birth of the Appalachian ranges marks the first of several mountain building plate collisions that culminated in the construction of Pangea with the Appalachians and neighboring Anti-Atlas mountains near the center. These mountain ranges likely once reached elevations similar to those of the Alps and the Rocky Mountains before they were eroded.

<span class="mw-page-title-main">Avalonia</span> Microcontinent in the Paleozoic era

Avalonia was a microcontinent in the Paleozoic era. Crustal fragments of this former microcontinent underlie south-west Great Britain, southern Ireland, and the eastern coast of North America. It is the source of many of the older rocks of Western Europe, Atlantic Canada, and parts of the coastal United States. Avalonia is named for the Avalon Peninsula in Newfoundland.

<span class="mw-page-title-main">Antler orogeny</span> Tectonic event from the Late Devonian into the Mississippian and early Pennsylvanian

The Antler orogeny was a tectonic event that began in the early Late Devonian with widespread effects continuing into the Mississippian and early Pennsylvanian. Most of the evidence for this event is in Nevada but the limits of its reach are unknown. A great volume of conglomeratic deposits of mainly Mississippian age in Nevada and adjacent areas testifies to the existence of an important tectonic event, and implies nearby areas of uplift and erosion, but the nature and cause of that event are uncertain and in dispute. Although it is known as an orogeny, some of the classic features of orogeny as commonly defined such as metamorphism, and granitic intrusives have not been linked to it. In spite of this, the event is universally designated as an orogeny and that practice is continued here. This article outlines what is known and unknown about the Antler orogeny and describes three current theories regarding its nature and origin.

<span class="mw-page-title-main">Taconic orogeny</span> Mountain-building period that affected most of New England

The Taconic orogeny was a mountain building period that ended 440 million years ago (Ma) and affected most of modern-day New England. A great mountain chain formed from eastern Canada down through what is now the Piedmont of the east coast of the United States. As the mountain chain eroded in the Silurian and Devonian periods, sediment spread throughout the present-day Appalachians and midcontinental North America.

<span class="mw-page-title-main">Caledonian orogeny</span> Mountain building event caused by the collision of Laurentia, Baltica and Avalonia

The Caledonian orogeny was a mountain-building cycle recorded in the northern parts of the British Isles, the Scandinavian Caledonides, Svalbard, eastern Greenland and parts of north-central Europe. The Caledonian orogeny encompasses events that occurred from the Ordovician to Early Devonian, roughly 490–390 million years ago (Ma). It was caused by the closure of the Iapetus Ocean when the Laurentia and Baltica continents and the Avalonia microcontinent collided.

<span class="mw-page-title-main">Variscan orogeny</span> Collision of tectonic plates resulting in the creation of mountains

The Variscan or Hercynianorogeny was a geologic mountain-building event caused by Late Paleozoic continental collision between Euramerica (Laurussia) and Gondwana to form the supercontinent of Pangaea.

The Rheic Ocean was an ocean which separated two major paleocontinents, Gondwana and Laurussia (Laurentia-Baltica-Avalonia). One of the principal oceans of the Paleozoic, its sutures today stretch 10,000 km (6,200 mi) from Mexico to Turkey and its closure resulted in the assembly of the supercontinent Pangaea and the formation of the Variscan–Alleghenian–Ouachita orogenies.

The Windermere Supergroup is a geological unit formed during the Ordovician to Silurian periods ~450 million years ago, and exposed in northwest England, including the Pennines and correlates along its strike, in the Isle of Man and Ireland, and down-dip in the Southern Uplands and Welsh Borderlands. It underlies much of north England's younger cover, extending south to East Anglia. It formed as a foreland basin, in a similar setting to the modern Ganges basin, fronting the continent of Avalonia as the remains of the attached Iapetus ocean subducted under Laurentia.

<span class="mw-page-title-main">Geology of Georgia (U.S. state)</span> Overview of the geology of the U.S. state of Georgia

The U.S. state of Georgia is commonly divided into four geologic regions that influence the location of the state's four traditional physiographic regions. The four geologic regions include the Appalachian foreland, Blue Ridge, Piedmont, and Coastal Plain. These four geologic regions commonly share names with and typically overlap the four physiographic regions of the state: the Appalachian Plateau and adjacent Valley and Ridge; the Blue Ridge; the Piedmont and the Coastal Plain.

<span class="mw-page-title-main">Laurentia</span> Craton forming the geological core of North America

Laurentia or the North American Craton is a large continental craton that forms the ancient geological core of North America. Many times in its past, Laurentia has been a separate continent, as it is now in the form of North America, although originally it also included the cratonic areas of Greenland and also the northwestern part of Scotland, known as the Hebridean Terrane. During other times in its past, Laurentia has been part of larger continents and supercontinents and consists of many smaller terranes assembled on a network of early Proterozoic orogenic belts. Small microcontinents and oceanic islands collided with and sutured onto the ever-growing Laurentia, and together formed the stable Precambrian craton seen today.

<span class="mw-page-title-main">Rhenohercynian Zone</span> Fold belt of west and central Europe, formed during the Hercynian orogeny

The Rhenohercynian Zone or Rheno-Hercynian zone in structural geology describes a fold belt of west and central Europe, formed during the Hercynian orogeny. The zone consists of folded and thrust Devonian and early Carboniferous sedimentary rocks that were deposited in a back-arc basin along the southern margin of the then existing paleocontinent Laurussia.

<span class="mw-page-title-main">Carolina terrane</span> Exotic terrane from central Georgia to central Virginia in the United States

The Carolina Terrane, also called the Carolina Superterrane or Carolinia, is an exotic terrane running ~370 miles (600 km) approximately North-South from central Georgia to central Virginia in the United States. It constitutes a major part of the eastern Piedmont Province.

<span class="mw-page-title-main">Iapetus Suture</span> Ancient geological fault

The Iapetus Suture is one of several major geological faults caused by the collision of several ancient land masses forming a suture. It represents in part the remains of what was once the Iapetus Ocean. Iapetus was the father of Atlas in Greek mythology, making his an appropriate name for what used to be called the 'Proto-Atlantic Ocean'. When the Atlantic Ocean opened, in the Cretaceous period, it took a slightly different line from that of the Iapetus suture, with some originally Laurentian rocks being left behind in north-west Europe and other, Avalonian, rocks remaining as part of Newfoundland.

The Massif Central is one of the two large basement massifs in France, the other being the Armorican Massif. The Massif Central's geological evolution started in the late Neoproterozoic and continues to this day. It has been shaped mainly by the Caledonian orogeny and the Variscan orogeny. The Alpine orogeny has also left its imprints, probably causing the important Cenozoic volcanism. The Massif Central has a very long geological history, underlined by zircon ages dating back into the Archaean 3 billion years ago. Structurally it consists mainly of stacked metamorphic basement nappes.

<span class="mw-page-title-main">Geology of Massachusetts</span>

The geology of Massachusetts includes numerous units of volcanic, intrusive igneous, metamorphic and sedimentary rocks formed within the last 1.2 billion years. The oldest formations are gneiss rocks in the Berkshires, which were metamorphosed from older rocks during the Proterozoic Grenville orogeny as the proto-North American continent Laurentia collided against proto-South America. Throughout the Paleozoic, overlapping the rapid diversification of multi-cellular life, a series of six island arcs collided with the Laurentian continental margin. Also termed continental terranes, these sections of continental rock typically formed offshore or onshore of the proto-African continent Gondwana and in many cases had experienced volcanic events and faulting before joining the Laurentian continent. These sequential collisions metamorphosed new rocks from sediments, created uplands and faults and resulted in widespread volcanic activity. Simultaneously, the collisions raised the Appalachian Mountains to the height of the current day Himalayas.

<span class="mw-page-title-main">Famatinian orogeny</span> Paleozoic geological event in South America

The Famatinian orogeny is an orogeny that predates the rise of the Andes and that took place in what is now western South America during the Paleozoic, leading to the formation of the Famatinian orogen also known as the Famatinian belt. The Famatinian orogeny lasted from the Late Cambrian to at least the Late Devonian and possibly the Early Carboniferous, with orogenic activity peaking about 490 to 460 million years ago. The orogeny involved metamorphism and deformation in the crust and the eruption and intrusion of magma along a Famatinian magmatic arc that formed a chain of volcanoes. The igneous rocks of the Famatinian magmatic arc are of calc-alkaline character and include gabbros, tonalites, granodiorites and trondhjemites. The youngest igneous rocks of the arc are granites.

The geology of Maine is part of the broader geology of New England and eastern North America.

Ganderia or Gander Terrane is a terrane in the northern Appalachians which broke off the supercontinent Gondwana c.570 million years ago (Ma) together with Avalonia, Megumia, and Carolinia.

References

  1. ↑ Ryder, RT; Swezey, CS; Crangle, RD Jr.; Trippi, MT (2008). Geologic cross section E-E' through the central Appalachian Basin from the Findlay Arch, Wood County, Ohio, to the Valley and Ridge Province, Pendleton County, West Virginia (Map). U.S. Geological Survey Scientific Investigations. SIM-2985.
  2. 1 2 3 4 PD-icon.svg This article incorporates public domain material from Valley and Ridge Province. United States Geological Survey . Retrieved 2009-01-08.
  3. ↑ Faill, Rodger T. (June 1997). "A Geologic History of the North-Central Appalachians. Part 1. Orogenesis from the Mesoproterozoic Through the Taconic Orogeny". American Journal of Science. 297 (6): 551–619. Bibcode:1997AmJS..297..551F. doi: 10.2475/ajs.297.6.551 .
  4. 1 2 3 4 5 6 Ettensohn, Frank R. (July 1987). "Rates of Relative Plate Motion During the Acadian Orogeny Based on the Spatial Distribution of Black Shales". The Journal of Geology. 95 (4): 572–582. Bibcode:1987JG.....95..572E. doi:10.1086/629150. JSTOR   30081087. S2CID   129501927.
  5. ↑ Blakey, Ron. "Paleogeography and Geologic Evolution of North America". Global Plate Tectonics and Paleogeography. Northern Arizona University. Archived from the original on 2008-06-21. Retrieved 2008-07-04.
  6. 1 2 3 4 5 6 Scotese, C.R.; McKerrow, W.S. (1990). "Palaeozoic, Palaeogeography and Biogeography". Geological Society Memoir. 12: 1–21. doi: 10.1144/GSL.MEM.1990.012.01.01 . Retrieved 24 April 2013.
  7. 1 2 3 4 Van Der Voo, Rob (March 1988). "Paleozoic paleogeography of North America, Gondwana, and intervening displaced terranes: Comparisons of paleomagnetism with paleoclimatology and biogeographical patterns". Geological Society of America Bulletin. 100 (3): 311–324. Bibcode:1988GSAB..100..311D. doi:10.1130/0016-7606(1988)100<0311:PPONAG>2.3.CO;2.
  8. ↑ Hibbard, J. P.; Van Staal, C. R.; Rankin, D. W. (2007). "A comparative analysis of pre-Silurian crustal building blocks of the northern and the southern Appalachian orogen". American Journal of Science. 307 (1): 23. Bibcode:2007AmJS..307...23H. doi: 10.2475/01.2007.02 . Retrieved 2009-02-06.
  9. 1 2 3 4 5 6 Ettensohn, Frank R. (2004). "Modeling the nature and development of major Paleozoic clastic wedges in the Appalachian Basin, USA". Journal of Geodynamics. 37 (3–5): 657–681. Bibcode:2004JGeo...37..657E. doi:10.1016/j.jog.2004.02.009.
  10. ↑ Park, Hyunmee; Barbeau, David L. Jr.; Rickenbaker, Alan; Bachmann-Krug, Denise; Gehrels, George (2010). "Application of Foreland Basin Detrital Zircon Geochronology to the Reconstruction of the Southern and Central Appalachian Orogen". The Journal of Geology. 118 (1): 23–44. Bibcode:2010JG....118...23P. doi:10.1086/648400. S2CID   39310243.
  11. 1 2 3 4 5 6 7 Ettensohn, Frank (1985). "The Catskill Delta complex and the Acadian Orogeny". The Catskill Delta. Geological Society of America. 39-49. doi:10.1130/SPE201-p39.
  12. ↑ Naylor, Richard S. (May 7, 1971). "Acadian Orogeny: An Abrupt and Brief Event". Science. 172 (3983): 558–560. Bibcode:1971Sci...172..558N. doi:10.1126/science.172.3983.558. JSTOR   1732547. PMID   17802216. S2CID   31398214.
  13. ↑ Bradley, Dwight C. (July 1983). "Tectonics of the Acadian Orogeny in New England and Adjacent Canada". The Journal of Geology. 91 (4): 381–400. Bibcode:1983JG.....91..381B. doi:10.1086/628785. S2CID   140201912.
  14. 1 2 Ettensohn, Frank R.; Brett, Carlton E. (2002). "Stratigraphic evidence from the Appalachian Basin for continuation of the Taconian orogeny into Early Silurian time". Physics and Chemistry of the Earth. 27 (1–3): 279–288. Bibcode:2002PCE....27..279E. doi:10.1016/S1474-7065(01)00010-9.
  15. ↑ Lash, Gary, G.; Engelder, Terry (January 2011). "Thickness trends and sequence stratigraphy of the Middle Devonian Marcellus Formation, Appalachian Basin: Implications for Acadian foreland basin evolution". AAPG Bulletin. 95 (1): 61–103. Bibcode:2011BAAPG..95...61L. doi:10.1306/06301009150.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  16. 1 2 Milici, Robert C.; Swezey, Christopher S. (2006). Assessment of Appalachian Basin Oil and Gas Resources: Devonian Shale-Middle and Upper Paleozoic Total Petroleum System (Report). United States Geological Survey. Open File Report 2006-1237. Retrieved 9 October 2016.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.