Geodynamic evolution of the northern Molucca Sea area (Eastern Indonesia) constrained by 3-D gravity field inversion

Widiwijayanti, Christina; Tiberi, Christel; Deplus, Christine; Diament, M.; Михайлов, В. О.; Louat, Rémy

doi:10.1016/j.tecto.2004.05.003

Cited by 25 publications

(28 citation statements)

References 31 publications

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“…The inversion retrieves the density contrasts within cells of 10‐ × 10‐ × 10‐km size over a 45‐km‐thick volume. A priori information is included as heterogeneous standard deviation distribution for the model parameters in order to take into account the information obtained with the former 2‐D models (e.g., Widiwijayanti et al, , for details). Initial a priori model is homogeneous with a zero density contrast for all layers, and we laterally extend the density model by approximately 100 km to overcome boundary effects.…”

Section: Gravimetric Data and Modelsmentioning

confidence: 99%

Western Mediterranean Subcontinental Mantle Emplacement by Continental Margin Obduction

et al. 2019

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Obduction is the tectonic process that results from thrusting of an oceanic lithosphere section (ophiolite) onto a continent. In contrast, thrusting of subcontinental mantle, observed in several mountain belts, remains a major unknown of plate tectonics. In the western Mediterranean, the Ronda and Beni Bousera peridotites are the largest worldwide subcontinental mantle exposure. From a geological point of view, the Ronda peridotites are exhumed by hyperstretching of the continental lithosphere in a back‐arc immediately followed by thrusting, explaining their present‐day position inside the Alboran crust. Using 2‐D and 3‐D modeling of new gravimetric data combined with local seismic tomography, we show that the Ronda peridotites are rooted inside the Alboran mantle along the entire Gibraltar arc. On these bases, we propose that the emplacement of the Ronda peridotites occurred in a back‐arc setting and corresponds to the thrusting of an entire hyper‐stretched continental margin onto a continent, a process that we define as continental margin obduction. This results from two successive deformation events: continental upper plate extension driven by slab roll‐back, immediately followed by upper plate shortening, likely triggered when a buoyant continental domain enters the subduction. We propose that this process affected the entire western Alboran domain, with peridotite bodies embedded within the crust along the whole Gibraltar Arc. We suggest that other examples such as the Alps Ivrea mantle body could likely represent continental margin obduction at the onset of continental collision.

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Section: Gravimetric Data and Modelsmentioning

confidence: 99%

Western Mediterranean Subcontinental Mantle Emplacement by Continental Margin Obduction

et al. 2019

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“…The method we use is based on a Bayesian approach in which any a priori information can be introduced in order to reduce the set of possible solutions (e.g. Widiwijayanti et al 2004). We invert the same data set as for the Oldenburg inversion (i.e.…”

Section: -D Density Modelmentioning

confidence: 99%

“…We then directly invert gravity data for lateral variations in density at specific depth levels (e.g. Widiwijayanti et al 2004). The integrated results of the study are presented in a forward model of crustal structure along a rift‐axis profile, which can explain available geological and geophysical data from the Main Ethiopian rift.…”

Section: Introductionmentioning

confidence: 99%

Inverse models of gravity data from the Red Sea-Aden-East African rifts triple junction zone

Tiberi

Ebinger

Ballu

et al. 2005

Geophysical Journal International

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SUMMARY The combined effects of stretching and magmatism permanently modify crustal structure in continental rifts and volcanic passive margins. The Red Sea–Gulf of Aden–Ethiopian rift triple junction zone provides a unique opportunity to examine incipient volcanic margin formation above or near an asthenospheric upwelling. We use gravity inversions and forward modelling to examine lateral variations in crust and upper mantle structure across the Oligocene flood basalt province, which has subsequently been extended to form the Red Sea, Gulf of Aden and Main Ethiopian rifts. We constrain and test the obtained models with new and existing seismic estimates of crustal thickness. In particular, we predict crustal thickness across the uplifted plateaux and rift valleys, and calibrate our results with recent receiver function analyses. We discuss the results together with a 3‐D distribution of density contrasts in terms of magmatic margin structure. The main conclusions are: (1) a denser (+240 kg m−3) and/or a thinner crust (23 km) in the triple junction zone of the Afar depression; (2) a shallower Moho is found along the Main Ethiopian rift axis, with crustal thickness values decreasing from 32–33 km in the south to 24 km beneath the southern Afar depression; (3) thicker crust (∼40 km) is present beneath the broad uplifted Oligocene flood basalt province, suggesting that crustal underplating compensates most of the plateau uplift and (4) possible magmatic underplating or a segmentation in the rift structure is observed at ∼8°N, 39°W beneath several collapsed caldera complexes. These results indicate that magmatism has profoundly changed crustal structure throughout the flood basalt province.

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“…In order to examine the geological significance of the load ratio, f , a 3‐D seismically constrained gravity inversion was carried out across the region. The technique of Jackson & Matsu'ura (1985) and Widiwijayanti et al (2003) uses maximum likelihood (Bayesian) statistics. The area is divided into layers and each layer is divided into boxes.…”

Section: Loading Of the Lithospherementioning

confidence: 99%

Wavelet and multitaper coherence methods for assessing the elastic thickness of the Irish Atlantic margin

Daly¹,

Brown

Stark

et al. 2004

Geophysical Journal International

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S U M M A R YThere have been some inconsistencies in estimates of the effective elastic thickness of the continental lithosphere Te based upon admittance or coherence relationships between gravity and topography. This paper compares multitaper and wavelet methods to analyse the coherence between Bouguer gravity and bathymetric data over the Irish Atlantic margin. The analyses show that similar lateral Te variations can be recovered from the data, but demonstrate that the size of the data window can give rise to a significant downward bias in Te estimates. A seismically constrained 3-D gravity inversion over the Rockall basin shows the presence of surface and subsurface loads whose ratio is loosely correlated with load ratio variations generated from the wavelet coherence method. The Te and load ratio, f variations can be plausibly related to major geological structures on the margin. If the load ratio variations can be interpreted geologically, it implies that spectral based methods to estimate effective elastic thickness must incorporate subsurface loads within the underlying theoretical model.On the Irish Atlantic margin, Te is generally low (6-18 km) and is associated with a NE-SW Caledonian trend. The weakest lithosphere is in the southern Rockall basin, Porcupine bank and Porcupine basin and the strongest lithosphere is along the Rockall-Hatton region. The low Te values are consistent with results from other passive margins. The reasons for such low Te values on the Irish Atlantic margin remain unclear, but may be the consequence of Te being frozen into the lithosphere when loads were emplaced during continental breakup and temperature gradients were high. The process of sedimentation and the presence of fluids may be contributory factors. There is an indication of a geological and rheological divide between the Rockall-Hatton region and the Rockall basin, possibly associated with the Caledonian orogenic front.

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Geodynamic evolution of the northern Molucca Sea area (Eastern Indonesia) constrained by 3-D gravity field inversion

Cited by 25 publications

References 31 publications

Western Mediterranean Subcontinental Mantle Emplacement by Continental Margin Obduction

Western Mediterranean Subcontinental Mantle Emplacement by Continental Margin Obduction

Inverse models of gravity data from the Red Sea-Aden-East African rifts triple junction zone

Wavelet and multitaper coherence methods for assessing the elastic thickness of the Irish Atlantic margin

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