Constraining South Atlantic Growth With Seafloor Spreading Data
نویسندگان
چکیده
The opening of the South Atlantic Ocean is one of the most extensively researched problems in plate kinematics. Models of it have proliferated since Bullard, Everett and Smith [8] published the first-ever computer-assisted reconstruction in the 60s. In recent years, focus has shifted to understanding the early stages of continental separation. General agreement exists about ocean opening being the result of the northward propagating mid-Atlantic ridge between two main tectonic plates, implying a certain degree of intracontinental deformation. Modern studies assign most of this intracontinental deformation to narrow mobile belts between large platelike continental blocks in order to achieve best fits of the blocks' extended continental margins [1-6]. The geological record of intracontinental deformation constrains the magnitude, orientation, and timing of block motion at very low resolution only. Similarly, with continent-ocean transition zones in the South Atlantic being up to 150 km wide, the ages and shapes of the extended margins are not unanimously interpretable at high resolution. Therefore, these are not suitable basis on which to lead a reconstruction effort. Aiming to avoid the uncertainties inherent in this approach, plate divergence has been modelled as depicted by seafloor spreading data (fracture zone traces and magnetic anomaly identifications), and this model has then been used as a context within which to interpret intracontinental tectonic motions [9].
منابع مشابه
Rapid South Atlantic spreading changes and coeval vertical motion in surrounding continents: Evidence for temporal changes of pressuredriven upper mantle flow
The South Atlantic region displays (1) a topographic gradient across the basin, with Africa elevated relative to South America, (2) a bimodal spreading history with fast spreading rates in Late Cretaceous and Eo-Oligocene, and (3) episodic regional uplift events in the adjacent continents concentrated in Late Cretaceous and Oligocene. Here we show that these observations can be linked by dynami...
متن کاملRecognizing detachment-mode seafloor spreading in the deep geological past
Large-offset oceanic detachment faults are a characteristic of slow- and ultraslow-spreading ridges, leading to the formation of oceanic core complexes (OCCs) that expose upper mantle and lower crustal rocks on the seafloor. The lithospheric extension accommodated by these structures is now recognized as a fundamentally distinct "detachment-mode" of seafloor spreading compared to classical magm...
متن کامل27th Annual Poster Session 1. Video Analysis of Reef Fishes and Live Bottom Seafloor Cover in the South Atlantic Bight 2. Correlating Solubility Parameters and Kamlet-taft Solvatochromic Parameters with the Self-assembly of Poly(3-hexylthiophene) in Mixtures of Organic Solvents
South Carolina Department of Natural Resources’ Marine Resource Monitoring, Assessment and Prediction Program (MARMAP) collects and analyzes data concerning the South Atlantic Bight’s commercially important snapper-grouper fishery to determine catch limits and conserve the region’s fishery. In addition to conventional trap capture-based data, MARMAP increasingly employs video recordings to dete...
متن کاملNonvolcanic seafloor spreading and corner-flow rotation
[1] Drilling during ODP Leg 209, dredging, and submersible dives have delineated an anomalous stretch of the Mid-Atlantic Ridge north and south of the 15 200N Fracture Zone. The seafloor here consists dominantly of mantle peridotite with gabbroic intrusions that in places is covered by a thin, discontinuous extrusive volcanic layer. Thick lithosphere (10–20 km) in this region inhibits magma fro...
متن کامل