Introduction to the thematic set: Tectonics and petroleum systems of East Africa – Part II

Macgregor, Duncan S.; Argent, John; Sansom, Pamela

doi:10.1144/petgeo2018-080

Cited by 2 publications

(1 citation statement)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…12C). The development of these sigmoidal faults probably occurred synchronously with the northward propagation of the rift (Macgregor et al, 2017). Smaller scale discrete fabrics in the upper crust also contribute to this pattern, as shown by previous analogue models of fabric reactivation (Corti et al, 2007).…”

Section: Tanganyika-rukwa Rift Segmentssupporting

confidence: 62%

Interactions between propagating rifts and linear weaknesses in the lower crust

2019

View full text Add to dashboard Cite

■ ABSTRACT Pre-existing structures in the crust such as shear zones, faults, and mobile belts are known to exert a significant control on the structural evolution of continental rifts. However, the influence of such features when the extension direction progressively changes over time remains uncertain. Here we present new results from three-dimensional lithospheric-scale laboratory experiments of rotational extension that provide key insights into the temporal evolution of propagating rifts. We specifically test and characterize how rifts propagate and interact with linear crustal rheological heterogeneities oriented at variable angles with respect to the extension direction. Results show that approximately rift-parallel pre-existing heterogeneities favor the formation of long, linear faults that reach near-final lengths at early stages. Low angles between the heterogeneities and the propagating rift axis may result in strong strikeslip reactivation of the pre-existing structures if they are suitably oriented with respect to the stretching direction. When the linear heterogeneities are oriented at intermediate to high angles rift branches become laterally offset as they propagate, resulting in complex rhombic fault patterns. Rift-perpendicular crustal heterogeneities do not affect fault trends during rift propagation, but cause stalling and deepening of laterally growing rift basins. Similarities between the analogue experimental results and selected natural examples provide insights on how nature finds the preferential pathway to breakup in heterogeneous continental lithosphere.

show abstract

Section: Tanganyika-rukwa Rift Segmentssupporting

confidence: 62%