From Ophiolites to Oceanic Crust: Sheeted Dike Complexes and Seafloor Spreading

2018 ◽  
pp. 459-492
Author(s):  
Jeffrey A. Karson
Keyword(s):  
Oceanic Crust ◽  
Seafloor Spreading

scholarly journals Bien Dong seafloor spreading and its influence to formation & development of sedimentary basins

2014 ◽  
Vol 17 (3) ◽  
pp. 132-138
Author(s):  
Hung Nguyen Manh ◽  
Tieng Hoang Dinh
Keyword(s):  
Continental Crust ◽  
Oceanic Crust ◽  
Sedimentary Basins ◽  
Seafloor Spreading ◽  
Fault System ◽  
Basalt Magma ◽  
Deep Fault ◽  
Thermal Anomalies ◽  
South West ◽  
Favorable Conditions

The paper presents the characteristics of Bien Dong seafloor spreading which including two parts: The Eastern part is quite large, in which developed by Eastern- Western orientation (spreading on N-S). The Southern- Western part gradually changed its orientation from E-W into East- North and in to South- West at the end (spreading SE- NW). There are two main dynamic resources created the spreading and deformation: The appearance of thermal abnormality by mantle plume occurred 36 M.a. until 14 M.a. The Eastern thermal anomalies continued to develop follow this orientation. In the SW- part the thermal anomalies changed it orientation from E-W into NE- SW 26 M.a and gradually developing toward S-W. Since 14 M.a, both two these trends been stopped, began to cooling and shrinkage. The abnormal existence caused pinchout and rifting the continental crust in Bien Dong Center and generating new oceanic crust as well. The uplift and variation of thermal abnormality (basalt magma) raised up the favorable conditions to forming, developing and varying the axis of Bien Dong spreading seafloor. The all above synthetic activities created favorable conditions for generation and development a series of deep fault systems with E-W direction in Eastern part and NE- SW direction in Southern-Western direction in remain part, and created and evolved the sedimentary basins in margins of Bien Dong with along the main deep fault system.

Crustal contamination and hybridization of an embryonic oceanic crust during the Red Sea rifting: An example from the Tihama Asir igneous complex, Saudi Arabia

2021 ◽  
Author(s):  
Valentin Basch ◽  
Alessio Sanfilippo ◽  
Luigi Vigliotti ◽  
Antonio Langone ◽  
Najeeb Rasul ◽  
...  
Keyword(s):  
Continental Crust ◽  
Oceanic Crust ◽  
Red Sea ◽  
Crustal Contamination ◽  
Seafloor Spreading ◽  
Rift System ◽  
Continental Rifting ◽  
Igneous Complex ◽  
Early Stages ◽  
Incompatible Elements

<p>The Red Sea rift system represents the best case study of the rift-to-drift history, i.e., the transition from a continental to an oceanic rift and the formation of passive margins. Although the onset of seafloor spreading has been constrained by geophysical observations to 5 Ma in the southern Red Sea, recent studies have suggested that MORB-type melts were intruded within the extended continental crust already during the early stages of rifting. We present here a petro-geochemical investigation of gabbroic bodies and associated basaltic intrusions from the Tihama Asir igneous complex, which formed as part of the intense magmatism that occurred during early Red Sea continental rifting. The most primitive olivine gabbros present modal, bulk and mineral compositions consistent with formation from MORB-type parental melts, but more evolved gabbros and oxide gabbros show saturation of phlogopite and define a geochemical evolution that progressively diverges from that of lower oceanic crust at mid-ocean ridges. Indeed, the Tihama Asir evolved gabbros are characterized by enrichments in LREE and highly incompatible elements (Rb, Ba, U, Th, Nb, Sr, K), suggesting hybridization of a MORB-type parental melt through a process of progressive assimilation of continental crust during the emplacement of gabbroic bodies. Additionally, the gabbros are associated with basaltic dike swarms intruded into the extending continental crust. The basalts show enrichments in LREE and highly incompatible elements similar to the gabbros, suggesting that they formed from melts extracted from the hybridized gabbroic crystal mush. This indicates that the Red Sea oceanization started before the onset of seafloor spreading, and that the cold continental crust was partially assimilated and replaced by hot gabbroic bodies since the early stages of continental rifting.</p>

Termination of a fossil continent-ocean fracture zone imaged with three-dimensional seismic data: The Chain Fracture Zone, eastern equatorial Atlantic

Geology ◽  
2005 ◽  
Vol 33 (8) ◽  
pp. 641-644 ◽  
Author(s):  
Richard J. Davies ◽  
Christopher J. MacLeod ◽  
Richard Morgan ◽  
Sepribo E. Briggs
Keyword(s):  
Oceanic Crust ◽  
Fracture Zone ◽  
Niger Delta ◽  
Three Dimensional ◽  
Seafloor Spreading ◽  
Spreading Center ◽  
Equatorial Atlantic ◽  
Half Graben ◽  
History Of ◽  
Subsequent Phase

Abstract We describe the first three-dimensional imaging of the termination of a continent-ocean fracture zone (COFZ), the Chain Fracture Zone, located offshore of the Niger Delta. The COFZ marks the abrupt transition between extended continental crust, comprising multiple half-graben, and oceanic crust that has a pervasive seafloor-spreading fabric. It preserves a history of continent-continent shearing followed by oceanic crust accretion and continent-ocean shearing during the inception of Atlantic rifting. The termination is marked by steeply dipping faults with sigmoidal planform and thrusts that probably formed as a result of continent-continent or continent-ocean shearing. These are crosscut by the seafloor-spreading fabric that formed during the subsequent phase of oceanic crust accretion. The accreted oceanic crust is cut by listric and planar faults that curve in the direction of the COFZ, where they terminate. The transition from continental to oceanic crust across the COFZ is sharp and resolvable to ∼100–200 m. Complexes of lava flows emanate from volcanoes along the COFZ, bifurcating and trifurcating down the volcano flanks. The volcanoes are 2–5.5 km wide and 1.4 km in height relative to adjacent oceanic crust and were injected at the COFZ, probably as the spreading center migrated along it.

An In Situ Section of Upper Oceanic Crust Created by Superfast Seafloor Spreading

2002 ◽  
Author(s):  
D.S. Wilson ◽  
D.A.H. Teagle ◽  
J.V. Firth ◽  
G.D. Acton
Keyword(s):  
Oceanic Crust ◽  
Seafloor Spreading

Evidence for forearc seafloor-spreading from the Betts Cove ophiolite, Newfoundland: oceanic crust of boninitic affinity

1998 ◽  
Vol 284 (3-4) ◽  
pp. 233-245 ◽  
Author(s):  
J.H. Bédard ◽  
K. Lauzière ◽  
A. Tremblay ◽  
A. Sangster
Keyword(s):  
Oceanic Crust ◽  
Seafloor Spreading

scholarly journals Margin-to-Margin Seafloor Spreading in the Eastern Gulf of Aden: A 16 Ma-Long History of Deformation and Magmatism from Seismic Reflection, Gravity and Magnetic Data

2021 ◽  
Vol 9 ◽  
Author(s):  
Morgane Gillard ◽  
Sylvie Leroy ◽  
Mathilde Cannat ◽  
Heather Sloan
Keyword(s):  
Oceanic Crust ◽  
Structural Characteristics ◽  
Seafloor Spreading ◽  
Magnetic Data ◽  
Data Sets ◽  
Gulf Of Aden ◽  
Potential Field Data ◽  
History Of ◽  
Ocean Ridge ◽  
Gravity And Magnetic Data

In this paper we present and analyze spreading-parallel seismic transects that image the oceanic crust in the eastern Gulf of Aden, from the Oman to the Socotra margins, across the active Sheba mid-oceanic ridge and between the Socotra-Hadbeen and Eastern Gulf of Aden Fracture Zones. The correlation of potential field data sets and gravity modelling allow us to document the spreading history of this oceanic basin from the onset of seafloor spreading ∼16 Ma-ago to the present. Two main oceanic sub-domains display distinct structural characteristics associated with different magmatic budgets at this mid-ocean ridge. In addition, we document the occurrence of a magmatic pulse at the Sheba Ridge around 11 Ma leading to the construction of a magmatic plateau in the western part of the studied area. This event led to substantial deformation and additional magmatism in previously formed oceanic crust. It could be related to an off-axis magmatic event previously identified in the adjacent Sheba segment, itself possibly related to the Afar plume.

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