Next Article in Journal
Using Cilioplankton as an Indicator of the Ecological Condition of Aquatic Ecosystems
Previous Article in Journal
Hydrology of Mountain Blocks in Arizona and New Mexico as Revealed by Isotopes in Groundwater and Precipitation
Open AccessArticle

Lithospheric Structure of a Transitional Magmatic to Amagmatic Continental Rift System—Insights from Magnetotelluric and Local Tomography Studies in the North Tanzanian Divergence, East African Rift

1
Géosciences Montpellier, UMR5243, Université de Montpellier, 34000 Montpellier, France
2
IMAGIR sarl, 29290 Saint Renan, France
3
Laboratoire Géosciences Océan, Institut Universitaire Européen de la Mer, 29280 Plouzané, France
4
Department of Physics, University of Dar Es Salaam, 35091 Dar Es Salaam, Tanzania
5
Department of Geology, University of Dar Es Salaam, 35091 Dar Es Salaam, Tanzania
*
Author to whom correspondence should be addressed.
Geosciences 2019, 9(11), 462; https://doi.org/10.3390/geosciences9110462
Received: 10 September 2019 / Revised: 17 October 2019 / Accepted: 24 October 2019 / Published: 29 October 2019
(This article belongs to the Special Issue The East African Rift: Tectonics, Magmatism and Natural Hazards)
Continental break-up is controlled by several parameters and processes (rheology, inherited structures, magmatism, etc). Their impact, chronology and interactions are still poorly known and debated, particularly when rifting interacts with cratons. In order to better understand the rifting initiation in a cratonic lithosphere, we analysed 22 magnetotelluric (MT) soundings collected along two East-West profiles in two different rift segments of the North Tanzanian Divergence. The North Tanzanian Divergence, where the East African Rift is at its earliest stage, is a remarkable example of the transition between magmatic to amagmatic rifting with two clearly identified segments. Only separated by a hundred kilometers, these segments, Natron (North) and Manyara (South), display contrasted morphological (wide versus narrow), volcanic (many versus a few edifices) and seismic (shallow versus deep activity) signatures. Magnetotelluric profiles across the two segments were inverted with a three-dimensional approach and supplied the resistive structure of the upper lithosphere (down to about 70 km). The Natron segment has a rather conductive lithosphere containing several resistive features (Proterozoic Belt), whereas the Manyara segment displays highly resistive blocks probably of cratonic nature encompassing a conductive structure under the axial valley. The joint interpretation of these models with recent local and regional seismological studies highlights totally different structures and processes involved in the two segments of the North Tanzanian Divergence. We identified contrasted CO2 content, magma upwelling or trapping, in depth regarding the Manyara or the Natron branch and the influence of inherited cratonic structures in the rifting dynamics. View Full-Text
Keywords: magnetotellurics; 3-D inversion; North Tanzanian Divergence; East African rift; lithospheric structure; CO2 content; seismology; joint interpretation magnetotellurics; 3-D inversion; North Tanzanian Divergence; East African rift; lithospheric structure; CO2 content; seismology; joint interpretation
Show Figures

Figure 1

MDPI and ACS Style

Plasman, M.; Hautot, S.; Tarits, P.; Gautier, S.; Tiberi, C.; Le Gall, B.; Mtelela, K.; Gama, R. Lithospheric Structure of a Transitional Magmatic to Amagmatic Continental Rift System—Insights from Magnetotelluric and Local Tomography Studies in the North Tanzanian Divergence, East African Rift. Geosciences 2019, 9, 462.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Back to TopTop