@article{fdi:010067610,
  title = {{L}ower crust exhumation during {P}aleoproterozoic ({E}burnean) orogeny, {NW} {G}hana, {W}est {A}frican {C}raton : interplay of coeval contractional deformation and extensional gravitational collapse},
  author = {{B}lock, {S}. and {J}essell, {M}ark and {A}illeres, {L}. and {B}aratoux, {L}enka and {B}ruguier, {O}. and {Z}eh, {A}. and {B}osch, {D}. and {C}aby, {R}. and {M}ensah, {E}.},
  editor = {},
  language = {{ENG}},
  abstract = {{W}e present new litho-structural and metamorphic maps of the {P}aleoproterozoic (2.25-2.00 {G}a) {W}est {A}frican {C}raton in northern {G}hana, based on the interpretation of field observations and airborne geophysical datasets. {T}he study reveals contrasting metamorphic domains consisting of high-grade gneisses and low-grade volcano-sedimentary belts, separated by shear zones and assembled during the {P}aleoproterozoic {E}burnean orogeny (2.15-2.07 {G}a). {S}upracrustal rocks were buried and metamorphosed at conditions corresponding to the amphibolite-granulite facies transition, during a ({D}1) deformation event, consistent with {N}-{S} horizontal shortening, which generated reverse shear zones. {H}igh and low metamorphic grade rocks were brought in contact along extensional shear zones formed during {N}-{S} extension ({D}2). {T}hese structures were overprinted by contractional deformation associated with {E}-{W} shortening and {N} to {NNE} stretching ({D}3), coeval with amphibolite-facies metamorphism. {T}he late-stage tectonic evolution ({D}4-{D}7) is characterised by strain localisation in successive generations of narrow shear zones, and the re-activation of inherited structures in a dominantly transcurrent regime. {U}-{P}b dating of zircon and monazite from magmatic and metamorphic rocks reveals that {D}1-{D}3 deformations form a continuous and overlapping time sequence between ca. 2140 and 2110 {M}a. {T}he changes in deformation style from {D}1 to {D}3 are interpreted to reflect a shift from dominant horizontal tectonic forces to an interplay between tectonic and gravitational forces, which allowed for the exhumation of the lower crust in an anatectic migmatite dome. {W}e suggest that doming is accommodated by lateral extensional sliding of the upper crust and amplified by coeval orthogonal shortening. {T}he abrupt rotation of shortening directions points to a change in boundary conditions applied to the orogen. {W}e hypothesise that it is due to the collision of northern {G}hana with the {P}aleoproterozoic province in modern-day south-western {B}urkina {F}aso, which shows a contrasting geological history. {T}he results reveal that the {E}burnean orogeny in {NW} {G}hana shared some thermo-mechanical similarities with modern orogenic belts. {T}he findings bring new insight in {P}aleoprotezozoic plate tectonics, at the transition between archaic and modern geodynamics.},
  keywords = {{W}est {A}frican craton ; {E}burnean orogeny ; {P}aleoproterozoic ; {A}natectic migmatite dome ; {C}ollision ; {A}rchean-{P}roterozoic transition ; {GHANA}},
  booktitle = {},
  journal = {{P}recambrian {R}esearch},
  volume = {274},
  numero = {},
  pages = {82--109},
  ISSN = {0301-9268},
  year = {2016},
  DOI = {10.1016/j.precamres.2015.10.014},
  URL = {https://www.documentation.ird.fr/hor/fdi:010067610},
}