Rifting, lithosphere breakup and volcanism: Comparison of magma-poor and volcanic rifted margins
TL;DR: In this paper, a detailed description of rift-onset and breakup unconformities is presented for the three continental margins that evolved in the Early Cretaceous, the Paleocene and the Oligocene, respectively.
About: This article is published in Marine and Petroleum Geology.The article was published on 2013-05-01. It has received 426 citations till now. The article focuses on the topics: Volcanic passive margin & Passive margin.
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TL;DR: The seafloor spreading history of the South China Sea has been interpreted in different ways in the past and the debate over the correct timing of the major tectonic events continues as discussed by the authors.
249 citations
TL;DR: In this article, a conceptual model for rift-evolution at conjugate magma-poor margins in time and space is presented, based on the early Cenozoic South China Sea rift architecture at the distal margins.
246 citations
TL;DR: In this article, the authors review the passive margins of the Atlantic and Indian oceans with the aim to evaluate the extent in which oceanic openings used former sutures and analyse the potential role of mantle plumes in continental break-up.
203 citations
Tongji University1, Geological Survey of Denmark and Greenland2, Cergy-Pontoise University3, California Institute of Technology4, Texas A&M University5, University of Padua6, University of Aberdeen7, University of Toulouse8, Chinese Academy of Sciences9, University of Sydney10, State Oceanic Administration11, Brigham Young University12, University of Louisiana at Lafayette13, Federal Fluminense University14, Shimane University15, University of Nebraska–Lincoln16, Japan Agency for Marine-Earth Science and Technology17, Peking University18, Jinan University19, West Virginia University20, Leibniz Institute of Marine Sciences21, University of Kiel22, China University of Geosciences (Wuhan)23, Nanjing University24, Woods Hole Oceanographic Institution25, Louisiana State University26, University of South Florida27, University of Pavia28, University of Bristol29, University of Lausanne30, National Centre for Antarctic and Ocean Research31, University of Iowa32, Ohio State University33, University of Tasmania34, Heidelberg University35, California State University, Sacramento36, Lamont–Doherty Earth Observatory37, National Taiwan University38, China University of Geosciences (Beijing)39, Purdue University40, Sun Yat-sen University41
TL;DR: In this paper, the authors report International Ocean Discovery Program drilling data from the northern South China Sea margin, testing the magma-poor margin model outside the North Atlantic, showing initiation of mid-Ocean Ridge basalt type magmatism during breakup, with a narrow and rapid transition into igneous oceanic crust.
Abstract: Continental breakup represents the successful process of rifting and thinning of the continental lithosphere, leading to plate rupture and initiation of oceanic crust formation. Magmatism during breakup seems to follow a path of either excessive, transient magmatism (magma-rich margins) or of igneous starvation (magma-poor margins). The latter type is characterized by extreme continental lithospheric extension and mantle exhumation prior to igneous oceanic crust formation. Discovery of magma-poor margins has raised fundamental questions about the onset of ocean-floor type magmatism, and has guided interpretation of seismic data across many rifted margins, including the highly extended northern South China Sea margin. Here we report International Ocean Discovery Program drilling data from the northern South China Sea margin, testing the magma-poor margin model outside the North Atlantic. Contrary to expectations, results show initiation of Mid-Ocean Ridge basalt type magmatism during breakup, with a narrow and rapid transition into igneous oceanic crust. Coring and seismic data suggest that fast lithospheric extension without mantle exhumation generated a margin structure between the two endmembers. Asthenospheric upwelling yielding Mid-Ocean Ridge basalt-type magmatism from normal-temperature mantle during final breakup is interpreted to reflect rapid rifting within thin pre-rift lithosphere.
168 citations
TL;DR: In this paper, the authors used multichannel seismic reflection and wide-angle seismic data sets to model the velocity structure of the incipient arc-continent collision along two trench perpendicular transects in the Bashi Strait between Taiwan and Luzon.
Abstract: [1] We use offshore multichannel seismic (MCS) reflection and wide-angle seismic data sets to model the velocity structure of the incipient arc-continent collision along two trench perpendicular transects in the Bashi Strait between Taiwan and Luzon. This area represents a transition from a tectonic regime dominated by subduction of oceanic crust of the South China Sea, west of the Philippines, to one dominated by subduction and eventual collision of rifted Chinese continental crust with the Luzon volcanic arc culminating in the Taiwan orogeny. The new seismic velocity models show evidence for extended to hyperextended continental crust, ~10–15 km thick, subducting along the Manila trench at 20.5°N along transect T1, as well as evidence indicating that this thinned continental crust is being structurally underplated to the accretionary prism at 21.5°N along transect T2, but not along T1 to the south. Coincident MCS reflection imaging shows highly stretched and faulted crust west of the trench along both transects and what appears to be a midcrustal detachment along transect T2, a potential zone of weakness that may be exploited by accretionary processes during subduction. An additional seismic reflection transect south of T1 shows subduction of normal ocean crust at the Manila trench.
157 citations
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4,094 citations
TL;DR: In this article, a three-layer crust consisting of upper, middle, and lower crust is divided into type sections associated with different tectonic provinces, in which P wave velocities increase progressively with depth and there is a large variation in average P wave velocity of the lower crust between different type sections.
Abstract: Geophysical, petrological, and geochemical data provide important clues about the composition of the deep continental crust. On the basis of seismic refraction data, we divide the crust into type sections associated with different tectonic provinces. Each shows a three-layer crust consisting of upper, middle, and lower crust, in which P wave velocities increase progressively with depth. There is large variation in average P wave velocity of the lower crust between different type sections, but in general, lower crustal velocities are high (>6.9 km s−1) and average middle crustal velocities range between 6.3 and 6.7 km s−1. Heat-producing elements decrease with depth in the crust owing to their depletion in felsic rocks caused by granulite facies metamorphism and an increase in the proportion of mafic rocks with depth. Studies of crustal cross sections show that in Archean regions, 50–85% of the heat flowing from the surface of the Earth is generated within the crust. Granulite terrains that experienced isobaric cooling are representative of middle or lower crust and have higher proportions of mafic rocks than do granulite terrains that experienced isothermal decompression. The latter are probably not representative of the deep crust but are merely upper crustal rocks that have been through an orogenic cycle. Granulite xenoliths provide some of the deepest samples of the continental crust and are composed largely of mafic rock types. Ultrasonic velocity measurements for a wide variety of deep crustal rocks provide a link between crustal velocity and lithology. Meta-igneous felsic, intermediate and mafic granulite, and amphibolite facies rocks are distinguishable on the basis of P and S wave velocities, but metamorphosed shales (metapelites) have velocities that overlap the complete velocity range displayed by the meta-igneous lithologies. The high heat production of metapelites, coupled with their generally limited volumetric extent in granulite terrains and xenoliths, suggests they constitute only a small proportion of the lower crust. Using average P wave velocities derived from the crustal type sections, the estimated areal extent of each type of crust, and the average compositions of different types of granulites, we estimate the average lower and middle crust composition. The lower crust is composed of rocks in the granulite facies and is lithologically heterogeneous. Its average composition is mafic, approaching that of a primitive mantle-derived basalt, but it may range to intermediate bulk compositions in some regions. The middle crust is composed of rocks in the amphibolite facies and is intermediate in bulk composition, containing significant K, Th, and U contents. Average continental crust is intermediate in composition and contains a significant proportion of the bulk silicate Earth's incompatible trace element budget (35–55% of Rb, Ba, K, Pb, Th, and U).
2,909 citations
"Rifting, lithosphere breakup and vo..." refers background in this paper
...P-wave velocities of continental lower crust seldom rise above 7.0 km/s; if so this is mainly confined to cratons or shields with a great crustal thickness (Hoolbrook et al., 1982; Rudnick and Fountain, 1995)....
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...0 km/s; if so this is mainly confined to cratons or shields with a great crustal thickness (Hoolbrook et al., 1982; Rudnick and Fountain, 1995)....
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01 Jan 2004
TL;DR: Gradstein et al. as discussed by the authors proposed a chronostratigraphy approach for linking time and rock in the context of geologic time scales, including the geomagnetic polarity time scale and stable isotope geochronology.
Abstract: Part I. Introduction: 1. Introduction F. M. Gradstein 2. Chronostratigraphy - linking time and rock F. M. Gradstein, J. G. Ogg and A. G. Smith Part II. Concepts and Methods: 3. Biostratigraphy F. M. Gradstein, R. A. Cooper and P. M. Sadler 4. Earth's orbital parameters and cycle stratigraphy L. A. Hinnov 5. The geomagnetic polarity time scale J. G. Ogg and A. G. Smith 6. Radiogenic isotope geochronology M. Villeneuve 7. Stable isotopes J. M. McArthur and R. J. Howarth 8. Geomathematics F. P. Agterberg Part III. Geologic Periods: 9. The Precambrian: the Archaen and Proterozoic eons L. J. Robb, A. H. Knoll, K. A. Plumb, G. A. Shields, H. Strauss and J. Veizer 10. Toward a 'natural' Precambrian time scale W. Bleeker 11. The Cambrian period J. H. Shergold and R. A. Cooper 12. The Ordovician period R. A. Cooper and P. M. Sadler 13. The Silurian period M. J. Melchin, R. A. Cooper and P. M. Sadler 14. The Devonian period M. R. House and F. M. Gradstein 15. The Carboniferous period V. Davydov, B. R. Wardlaw and F. M. Gradstein 16. The Permian period B. R. Wardlaw, V. Davydov and F. M. Gradstein 17. The Triassic period J. G. Ogg 18. The Jurassic period J. G. Ogg 19. The Cretaceous Period J. G. Ogg, F. P. Agterberg and F. M. Gradstein 20. The Paleogene period H. P. Luterbacher, J. R. Ali, H. Brinkhuis, F. M. Gradstein, J. J. Hooker, S. Monechi, J. G. Ogg, J. Powell, U. Rohl, A. Sanfilippo, and B. Schmitz 21. The Neogene period L. Lourens, F. Hilgen, N. J. Shackleton, J. Laskar and D. Wilson 22. The Pleistocene and Holocene epochs P. Gibbard and T. van Kolfschoten Part IV. Summary: 23. Construction and summary of the geologic time scale F. M.. Gradstein, J. G. Ogg and A. G. Smith Appendices Bibliography Stratigraphic index General index.
2,890 citations
TL;DR: In this paper, the authors show that the production of magmatically active rifted margins and the effusion of flood basalts onto the adjacent continents can be explained by a simple model of rifting above a thermal anomaly in the underlying mantle.
Abstract: When continents rift to form new ocean basins, the rifting is sometimes accompanied by massive igneous activity. We show that the production of magmatically active rifted margins and the effusion of flood basalts onto the adjacent continents can be explained by a simple model of rifting above a thermal anomaly in the underlying mantle. The igneous rocks are generated by decompression melting of hot asthenospheric mantle as it rises passively beneath the stretched and thinned lithosphere. Mantle plumes generate regions beneath the lithosphere typically 2000 km in diameter with temperatures raised 100–200°C above normal. These relatively small mantle temperature increases are sufficient to cause the generation of huge quantities of melt by decompression: an increase of 100°C above normal doubles the amount of melt whilst a 200°C increase can quadruple it. In the first part of this paper we develop our model to predict the effects of melt generation for varying amounts of stretching with a range of mantle temperatures. The melt generated by decompression migrates rapidly upward, until it is either extruded as basalt flows or intruded into or beneath the crust. Addition of large quantities of new igneous rock to the crust considerably modifies the subsidence in rifted regions. Stretching by a factor of 5 above normal temperature mantle produces immediate subsidence of more than 2 km in order to maintain isostatic equilibrium. If the mantle is 150°C or more hotter than normal, the same amount of stretching results in uplift above sea level. Melt generated from abnormally hot mantle is more magnesian rich than that produced from normal temperature mantle. This causes an increase in seismic velocity of the igneous rocks emplaced in the crust, from typically 6.8 km/s for normal mantle temperatures to 7.2 km/s or higher. There is a concomitant density increase. In the second part of the paper we review volcanic continental margins and flood basalt provinces globally and show that they are always related to the thermal anomaly created by a nearby mantle plume. Our model of melt generation in passively upwelling mantle beneath rifting continental lithosphere can explain all the major rift-related igneous provinces. These include the Tertiary igneous provinces of Britain and Greenland and the associated volcanic continental margins caused by opening of the North Atlantic in the presence of the Iceland plume; the Parana and parts of the Karoo flood basalts together with volcanic continental margins generated when the South Atlantic opened; the Deccan flood basalts of India and the Seychelles-Saya da Malha volcanic province created when the Seychelles split off India above the Reunion hot spot; the Ethiopian and Yemen Traps created by rifting of the Red Sea and Gulf of Aden region above the Afar hot spot; and the oldest and probably originally the largest flood basalt province of the Karoo produced when Gondwana split apart. New continental splits do not always occur above thermal anomalies in the mantle caused by plumes, but when they do, huge quantities of igneous material are added to the continental crust. This is an important method of increasing the volume of the continental crust through geologic time.
2,821 citations
"Rifting, lithosphere breakup and vo..." refers background in this paper
...…breakup of continents (e.g. Richards et al., 1989), or that hot material accumulates at the base of the lithosphere so that lithospheric thinning and decompression melting during rifting generates much greater amounts of magma than at over mantle of normal temperature (White and McKenzie, 1989)....
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..., 2002) and over whether plumes initiate rifting, or rifting focuses plume activity (Foulger and Natland, 2003; King and Anderson, 1998; Sleep, 1971; White and McKenzie, 1989)....
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...White and McKenzie (1989) predicted from lower crustal velocity of normal oceanic crust (igneous crustal thickness of 7.1 ± 0.8 km (White et al., 1992)) which has been observed to be around 6.9 km/s that velocities of 6.9 to 7.2 km/s are the possible outcome of the melting of mantle....
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..., 1989), or that hot material accumulates at the base of the lithosphere so that lithospheric thinning and decompression melting during rifting generates much greater amounts of magma than at over mantle of normal temperature (White and McKenzie, 1989)....
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...…controversy on the mechanism responsible for the production of large volumes of basaltic volcanism (Menzies et al., 2002) and over whether plumes initiate rifting, or rifting focuses plume activity (Foulger and Natland, 2003; King and Anderson, 1998; Sleep, 1971; White and McKenzie, 1989)....
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TL;DR: The concept of crustal plate motion over mantle hotspots has been advanced to explain the origin of the Hawaiian and other island chains and the origin the Walvis, Iceland-Farroe and other aseismic ridges as discussed by the authors.
Abstract: THE concept of crustal plate motion over mantle hotspots has been advanced1 to explain the origin of the Hawaiian and other island chains and the origin of the Walvis, Iceland-Farroe and other aseismic ridges. More recently the pattern of the aseismic ridges has been used in formulating continental reconstructions2. I have shown3 that the Hawaiian-Emperor, Tuamotu-Line and Austral-Gilbert-Marshall island chains can be generated by the motion of a rigid Pacific plate rotating over three fixed hotspots. The motion deduced for the Pacific plate agrees with the palaeomagnetic studies of seamounts4. It has also been found that the relative plate motions deduced from fault strikes and spreading rates agree with the concept of rigid plates moving over fixed hotspots. Fig. 1 shows the absolute motion of the plates over the mantle, a synthesis which satisfies the relative motion data and quite accurately predicts the trends of the island chains and aseismic ridges away from hotspots.
2,277 citations
"Rifting, lithosphere breakup and vo..." refers background in this paper
...Such mantle plumes (Morgan, 1971), also referred to as hot-spots rise diapirically from the core–mantle boundary through the lower mantle and, upon reaching density equilibrium spread out variably at mantle discontinuities....
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...12), respectively, are commonly referred to the influence of the Tristan da Cunha hot-spot with the Walvis Ridge and Rio Grande Rise as the expression of the plume tail (Morgan, 1971; Wilson, 1963)....
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