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Melt infiltration of the lower lithosphere beneath the Tanzania craton and the Albertine rift inferred from S receiver functions
2012
[1] The transition between the lithosphere and the asthenosphere is subject to numerous contemporary studies as its nature is still poorly understood. The thickest lithosphere is associated with old cratons and platforms and it has been shown that seismic investigations may fail to image the lithosphere-asthenosphere boundary in these areas. Instead, several recent studies have proposed a mid-lithospheric discontinuity of unknown origin existing under several cratons. In this study we investigate the Tanzania craton in East Africa which is enclosed by the eastern and western branches of the East African Rift System. We present evidence from S receiver functions for two consecutive discontin…
Influence of pre-existing fabrics on fault kinematics and rift geometry of interacting segments: Analogue models based on the Albertine Rift (Uganda)…
2011
This study aims at showing how far pre-existing crustal weaknesses left behind by Proterozoic mobile belts, that pass around cratonic Archean shields (Tanzania Craton to the southeast and Congo Craton to the northwest), control the geometry of the Albertine Rift. Focus is laid on the development of the Lake Albert and Lake Edward/George sub-segments and between them the greatly uplifted Rwenzori Mountains, a horst block located within the rift and whose highest peak rises to >5000 m above mean sea level. In particular we study how the southward propagating Lake Albert sub-segment to the north interacts with the northward propagating Lake Edward/George sub-segment south of it, and how this i…
Rifted margin formation in the South Tyrrhenian Sea: A high resolution profile across the North Sicily passive continental margin.
2000
A new, 150 km long seismic line across the continental margin of north Sicily has been acquired and interpreted. The overall structure of the margin is controlled by extension, which caused crustal thinning and widespread normal faulting. Two main thinned zones are observed in the south in correspondence with the Cafalù basin and farther to the north at the continent-ocean transition. Zones of thinned crust coincide with zones of intense normal faulting. Extension began in late Tortonian times and caused the opening of the Cefalù basin controlled by a northward dipping listric fault. Messinian stretching affected most of the future margin and provoked a widening of the Cefalù basin and norm…
Astronomical dating of two Pliocene alkaline volcanic ash layers in the Capo Rossello area (southern Sicily, Italy): implications for the beginning o…
2009
Key-words. - Sicily Channel rift, Biostratigraphy, Astronomical calibration, Pliocene, Volcanic ash layers. Abstract. - Two volcaniclastic ash layers (AL1 and AL2) are intercalated throughout the middle Pliocene sedimentary sequences of Punta Piccola and Capo Rossello exposed along the south coast of Sicily (Italy). Astronomical calibration of the Punta Piccola section provided an age of 2.676 Ma for the deposition of the AL1 layer. The high-resolution bio-cyclostratigraphy of the Capo Rossello section, in combination with detailed correlations with previously astrono- mically calibrated coeval sequences, provided an age of 2.225 Ma for the deposition of the AL2 layer. Mineralogical, petrog…
Fault-controlled Soil CO2 Degassing and Shallow Magma Bodies: Summit and Lower East Rift of Kilauea Volcano (Hawaii), 1997
2006
Soil CO2 flux measurements were carried out along traverses across mapped faults and eruptive fissures on the summit and the lower East Rift Zone of Kilauea volcano. Anomalous levels of soil degassing were found for 44 of the tectonic structures and 47 of the eruptive fissures intercepted by the surveyed profiles. This result contrasts with what was recently observed on Mt. Etna, where most of the surveyed faults were associated with anomalous soil degassing. The difference is probably related to the differences in the state of activity at the time when soil gas measurements were made: Kilauea was erupting, whereas Mt. Etna was quiescent although in a pre-eruptive stage. Unlike Mt. Etna, fl…
Rift-controlled fluvial/tidal transitional series in the Oukai¨meden Sandstones, High Atlas of Marrakesh (Morocco)
1996
Abstract The Carnian formation of the Oukai¨meden Sandstones was deposited in the northwestern corner of the African craton along tectonic troughs grouped as a WSW-ENE rift system on the southwestern margin of the Tethys. Red sandstones represent mainly distal braided-stream deposits where very extensive sand flats with 3D dunes, 2D sand waves and high-regime horizontally laminated sandstones predominate. The similarities in orientation between current patterns and trough border faulting, the sudden large variations in the thickness of deposits and the occurrence of lateral alluvial fans along the marginal faults are all evidence of the tectonic control of sedimentation. The middle part of …
New rodent faunas from Middle Miocene and Mio- Pliocene in the Cabriel Basin (Valencia, Spain)
2011
Five new localities with micromammal remains have been located in the Cabriel Basin. These localities are situated in the eastern area of the Cabriel Basin, in the Juan Vich ravine, where the oldest deposits of this basin crop out. The localities JV2, JV3 and JV6 are of Middle Miocene age, JVTLI1 of Middle Miocene or Late Miocene age and JVTS1 of Late Miocene or Early Pliocene age. The beginning of the sedimentary history of the basin was attributed to Late Turolian (Late Miocene). The new sedimentary record from the Juan Vich ravine and the mammalian findings extend the stratigraphic and paleontological knowledge of the Basin.
Contrasting styles of deep-marine pyroclastic eruptions revealed from Axial Seamount push core records
2015
Abstract A comprehensive understanding of explosive basaltic eruption processes in the deep-sea relies upon detailed analysis and comparison of the variety of volcaniclastic lithologies on the seafloor, which has been challenged by insufficient sample recovery. A dedicated ROV-based sampling approach using long push cores offers an unparalleled opportunity to fully characterize the diversity of unconsolidated volcaniclastic lithofacies on a recently active seamount. Lithofacies from Axial Seamount record two styles of pyroclastic eruptions, strombolian and phreatomagmatic, at 1.5 km water depth. Strombolian eruptions are represented by abundant fluidal and highly vesicular (up to 50%) vitri…
Ash resuspension related to the 2011–2012 Cordón Caulle eruption, Chile, in a rural community of Patagonia, Argentina
2017
Abstract The 2011–2012 Cordon Caulle eruption emitted about 1 km3 of rhyodacitic tephra. Dominant westerly winds in the region caused most of the primary tephra to deposit in neighboring Argentina. In addition to the impact of widespread dispersal and fallout of primary tephra during the eruption, Argentina was also significantly affected by remobilization of the primary ash even several years after the climactic phase of the eruption. In this mixed methods study, we combine aspects of natural and social sciences to characterize the ash resuspension events associated with the 2011–2012 Cordon Caulle deposits and assess the impacts on the Argentinian farming community of Ingeniero Jacobacci …
The “Camporeale wedge-top Basin” (NW Sicily; Italy) in the frame of the Late Miocene Sicilian Foreland Basin System; Inferences from the Upper Torton…
2011
Abstract Since the latest Oligocene–earliest Miocene the building of the Sicilian fold and thrust belt has been accompanied by development of a “peripheral” foreland basin system which migrated toward the foreland. In north-western Sicily, the sedimentary record of the foreland basin system migration is represented by a stratigraphic succession made up of several lithostratigraphic units, bounded by regional unconformity surfaces, deposited recording at least four main sedimentary phases, each characterized by the development of different types of syntectonic basins. In particular, during the Late Miocene (Late Tortonian to Early Messinian) a wide wedge-top depozone developed in the innermo…