TY  - JOUR
A1  - Sippel, Judith
A1  - Meessen, Christian
A1  - Cacace, Mauro
A1  - Mechie, James
A1  - Fishwick, Stewart
A1  - Heine, Christian
A1  - Scheck-Wenderoth, Magdalena
A1  - Strecker, Manfred
T1  - The Kenya rift revisited
BT  - insights into lithospheric strength through data-driven 3-D gravity and thermal modelling
JF  - Solid earth
N2  - We present three-dimensional (3-D) models that describe the present-day thermal and rheological state of the lithosphere of the greater Kenya rift region aiming at a better understanding of the rift evolution, with a particular focus on plume-lithosphere interactions. The key methodology applied is the 3-D integration of diverse geological and geophysical observations using gravity modelling. Accordingly, the resulting lithospheric-scale 3-D density model is consistent with (i) reviewed descriptions of lithological variations in the sedimentary and volcanic cover, (ii) known trends in crust and mantle seismic velocities as revealed by seismic and seismological data and (iii) the observed gravity field. This data-based model is the first to image a 3-D density configuration of the crystalline crust for the entire region of Kenya and northern Tanzania. An upper and a basal crustal layer are differentiated, each composed of several domains of different average densities. We interpret these domains to trace back to the Precambrian terrane amalgamation associated with the East African Orogeny and to magmatic processes during Mesozoic and Cenozoic rifting phases. In combination with seismic velocities, the densities of these crustal domains indicate compositional differences. The derived lithological trends have been used to parameterise steady-state thermal and rheological models. These models indicate that crustal and mantle temperatures decrease from the Kenya rift in the west to eastern Kenya, while the integrated strength of the lithosphere increases. Thereby, the detailed strength configuration appears strongly controlled by the complex inherited crustal structure, which may have been decisive for the onset, localisation and propagation of rifting.
Y1  - 2017
U6  - https://doi.org/10.5194/se-8-45-2017
SN  - 1869-9510
SN  - 1869-9529
VL  - 8
SP  - 45
EP  - 81
PB  - Copernicus
CY  - Göttingen
ER  - 
TY  - JOUR
A1  - Oncken, Onno
A1  - Luschen, Ewald
A1  - Mechie, James
A1  - Sobolev, Stephan Vladimir
A1  - Schulze, Albrecht
A1  - Gaedicke, Christoph
A1  - Grunewald, Steffen
A1  - Bribach, Jens
A1  - Asch, Günter
A1  - Giese, Peter
A1  - Wigger, Peter
A1  - Schmitz, Michael
A1  - Lueth, Stefan
A1  - Scheuber, Ekkehard
A1  - Haberland, Christian
A1  - Rietbrock, Andreas
A1  - Götze, Hans-Jürgen
A1  - Brasse, Heinrich
A1  - Patzwahl, Regina
A1  - Chong, Guillermo
A1  - Wilke, Hans-Gerhard
A1  - Gonzalez, Gabriel
A1  - Jensen, Arturo
A1  - Araneda, Manuel
A1  - Vieytes, Hugo
A1  - Behn, Gerardo
A1  - Martinez, Eloy
T1  - Seismic reflection image revealing offset of Andean subduction-zone earthquake locations into oceanic mantle
Y1  - 1999
ER  - 
TY  - JOUR
A1  - Dahm, Torsten
A1  - Stiller, Manfred
A1  - Mechie, James
A1  - Heimann, Sebastian
A1  - Hensch, Martin
A1  - Woith, Heiko
A1  - Schmidt, Bernd
A1  - Gabriel, Gerald
A1  - Weber, Michael
T1  - Seismological and geophysical signatures of the deep crustal magma systems of the cenozoic volcanic fields Beneath the Eifel, Germany
JF  - Geochemistry, geophysics, geosystems
N2  - The Quaternary volcanic fields of the Eifel (Rhineland-Palatinate, Germany) had their last eruptions less than 13,000 years ago. Recently, deep low-frequency (DLF) earthquakes were detected beneath one of the volcanic fields showing evidence of ongoing magmatic activity in the lower crust and upper mantle. In this work, seismic wide- and steep-angle experiments from 1978/1979 and 1987/1988 are compiled, partially reprocessed and interpreted, together with other data to better determine the location, size, shape, and state of magmatic reservoirs in the Eifel region near the crust-mantle boundary. We discuss seismic evidence for a low-velocity gradient layer from 30-36 km depth, which has developed over a large region under all Quaternary volcanic fields of the Rhenish Massif and can be explained by the presence of partial melts. We show that the DLF earthquakes connect the postulated upper mantle reservoir with the upper crust at a depth of about 8 km, directly below one of the youngest phonolitic volcanic centers in the Eifel, where CO(2)originating from the mantle is massively outgassing. A bright spot in the West Eifel between 6 and 10 km depth represents a Tertiary magma reservoir and is seen as a model for a differentiated reservoir beneath the young phonolitic center today. We find that the distribution of volcanic fields is controlled by the Variscan lithospheric structures and terrane boundaries as a whole, which is reflected by an offset of the Moho depth, a wedge-shaped transparent zone in the lower crust and the system of thrusts over about 120 km length.
KW  - magma reservoirs
KW  - distributed volcanic fields
KW  - reflection seismic
KW  - crustal magma chamber
KW  - deep low-frequency earthquakes
KW  - low velocity zone
Y1  - 2020
U6  - https://doi.org/10.1029/2020GC009062
SN  - 1525-2027
VL  - 21
IS  - 9
PB  - American Geophysical Union
CY  - Washington
ER  -