Magmatism and rift margin evolution: Evidence from northwest Australia

Hopper, John R.; Mutter, John C.; Larson, Roger L.; Mutter, Carolyn Z.

doi:10.1130/0091-7613(1992)020<0853:marmee>2.3.co;2

Cited by 99 publications

(92 citation statements)

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“…Flow of lavas onto continental crust and pervasive intrusions inhibit seismic resolution and commonly hide rift structures. The apparent lack of extensional features has led to models of very rapid breakup of the continental lithosphere without significant rifting (Mutter et al 1984;Larsen 1990;Hopper et al 1992). In contrast, we show that a protracted rift phase is compatible with data from many margins.…”

Section: Tectono-magmatic D#nensionssupporting

confidence: 60%

“…There are no obvious plumes to explain the US East Coast (Holbrook & Kelemen 1993;Talwani et al 1995) and West Australia margins (Mutter et al 1984;Hopper et al 1992;Colwell et al 1994), although a plume relationship was inferred by Wilson (1997) for the US East Coast and the conjugate West Africa margins. The inferred volcanic margin-plume relationship is commonly based on less excessive, persistent volcanism caused by the tail of the plume, and recognized by a submarine ridge or seamount chain such as the Iceland and Tristan plume trails expressed by the Greenland-IcelandFaeroe ridge (Fig.…”

Section: Volcanic Margins and Mantle Plumesmentioning

confidence: 99%

“…The similarity in tectonic style of volcanic or nonvolcanic margins suggests that the classification in Fig. 1 (Mutter et al, 1989, Hopper et al 1992Planke et al 1996).…”

Section: Volcanic Margins and Mantle Plumesmentioning

confidence: 99%

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Atlantic volcanic margins: a comparative study

Eldholm

Gladczenko

Skogseid

et al. 2000

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Volcanic margins in the Atlantic Ocean reveal a series of common crustal units and structural features developed during continental extension and break-up. We suggest that four main crustal zones can be recognized on volcanic margins. This tectono-magmatic zonation implies a history of development where tectonic and magmatic styles and dimensions depend on the interaction of lithospheric and asthenospheric properties and dynamics. The amount of excess igneous activity depends on the temperature and fluid content of the asthenosphere along the incipient plate boundary and the dynamic history of the lithosphere during the rift phase. An adequate understanding of the margin history requires studies of the entire rift, i.e. the conjugate margins. We also note that the spectacular wedges of seaward-dipping reflectors observed along many rifted margins are only one of many igneous features originating during the process of break-up and initial seafloor spreading. Probably, most passive rifted margins represent intermediate cases relative to the volcanic and non-volcanic end-members. A mantle plume impinging on lithosphere already under extension emplacing Large Igneous Province-type initial oceanic crust, including an extensive extrusive cover, is considered the most likely explanation for volcanic margins. Hydrocarbon resource evaluations of volcanic margins have to include their characteristic tectono-magmatic features and their consequences for vertical motion, erosion, sedimentation, thermal and burial histories, and maturation.

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Section: Tectono-magmatic D#nensionssupporting

confidence: 60%

Section: Volcanic Margins and Mantle Plumesmentioning

confidence: 99%

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Atlantic volcanic margins: a comparative study

Eldholm

Gladczenko

Skogseid

et al. 2000

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“…Like the central North Atlantic margin, the Norwegian margin is a volcanic passive margin [e.g., Hinz, 1981;Hinz et al, 1993], and parts of the Northwest Shelf of Australia are volcanic [Hopper et al, 1992]. On the Norwegian margin, inversion began soon after the initiation of seafloor spreading [Vågnes et al, 1998] and continued into Miocene time.…”

Section: Applications To Other Passive Marginsmentioning

confidence: 99%

Relative timing of CAMP, rifting, continental breakup, and basin inversion: Tectonic significance

Schlische

Withjack

Olsen

2003

Geophysical Monograph Series

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“…In the past decade or so, there have been an increasing number of deep-crustal seismic investigations on rifted continental margins, which have often revealed thick igneous crust at continent-ocean transition zones [LASE Study Group, 1986;White et al, 1987; TrThu et al, 1989;Zehnder et al, 1990;Hopper et al, 1992;Holbrook and Kelemen, 1993]. The thick igneous crust at these volcanic passive margins is typically 20-30 km thick, and its lower-crustal velocity is usually higher than 7.2 km/s.…”

Section: Introductionmentioning

confidence: 99%

Magmatism and dynamics of continental breakup in the presence of a mantle plume

Korenaga¹

2000

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This thesis studies the dynamics of mantle melting during continental breakups by geophysical, geochemical, and numerical analyses. The first part focuses on the mantle melting and crustal accretion processes during the formation of the Southeast Greenland margin, on the basis of deep-crustal seismic data. A new seismic tomographic method is developed to jointly invert refraction and reflection travel times for a compressional velocity structure, and a long-wavelength structure with strong lateral heterogeneity is successfully recovered, including 30-to 15-km-thick igneous crust within a 150-km-wide continent-ocean transition zone. A nonlinear Monte Carlo analysis is also conducted to establish the absolute uncertainty of model parameters. The derived crustal structure is first used to resolve the origin of a margin gravity high, with new inversion schemes using both seismic and gravity constraints. Density anomalies producing the gravity high seem to be confined within the upper crust, not in the lower crust as suggested for other volcanic margins. A new robust framework is then developed for the petrological interpretation of the velocity structure of igneous crust, and the thick igneous crust formed at the continentocean transition zone is suggested to have resulted from vigorous active upwelling of mantle with only somewhat elevated potential temperature. In the second part, the nature of mantle melting during the formation of the North Atlantic igneous province is studied on the basis of the major element chemistry of erupted lavas. A new fractionation correction scheme based on the Ni concentrations of mantle olivine is used to estimate primary melt compositions, which suggest that this province is characterized by a large degree of major element source heterogeneity. In the third part, the nature of preexisting sublithospheric convection is investigated by a series of finite element analyses, because the strength of such convection is important to define the "normal" state of mantle, the understanding of which is essential to identify any anomalous behavior of mantle such as a mantle plume. The results suggest that small-scale convection is likely in normal asthenosphere, and that the upwelling velocity in such convection is on the order of 1-10 cm/yr. 271 Introductory NotesThis thesis is composed of three parts, all of which are related to the dynamics of mantle melting during continental breakups. In the first part, rifting magmatism associated with the opening of the North Atlantic (at -60 Ma) is investigated on the basis of deep-crustal seismic data collected across the Southeast Greenland continental margin. A new seismic tomographic method is developed to jointly invert refraction and reflection travel times for a two-dimensional velocity structure (Chapter 1). Several key issues in travel time tomography such as velocity-depth ambiguity and absolute parameter uncertainty are identified, and a practical strategy is presented to resolve them. The derived crustal velocity structure is the...

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Magmatism and rift margin evolution: Evidence from northwest Australia

Cited by 99 publications

References 0 publications

Atlantic volcanic margins: a comparative study

Atlantic volcanic margins: a comparative study

Relative timing of CAMP, rifting, continental breakup, and basin inversion: Tectonic significance

Magmatism and dynamics of continental breakup in the presence of a mantle plume

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