@article{fdi:010084404,
  title = {{T}he origin of the potassium-rich annular zones at the {B}osumtwi impact structure, {G}hana, investigated by field study, radiometric analysis, and first cosmogenic nuclide data},
  author = {{N}iang, {C}. {A}. {B}. and {B}aratoux, {D}avid and {R}ochette, {P}. and {B}raucher, {R}. and {R}eimold, {W}. {U}. and {L}ambert, {P}. and {D}iallo, {D}. {P}. and {R}egard, {V}. and {C}arretier, {S}{\'e}bastien and {J}essell, {M}. {W}. and {F}aye, {G}. and {K}oeberl, {C}.},
  editor = {},
  language = {{ENG}},
  abstract = {{T}he 10.5-km-diameter, 1 {M}a {B}osumtwi impact structure in {G}hana is one of the youngest, large impact structures known on {E}arth. {T}he preservation of the morphology of its ejecta deposits, with an annular moat and outer ridge resembling those of rampart impact craters on {M}ars, makes {B}osumtwi a remarkable impact structure on the {A}frican continent. {A}n airborne radiometric survey of the southwestern part of {G}hana reveals enigmatic circular feature enriched in potassium, coinciding with the crater rim and an outer ejecta ridge at {B}osumtwi. {T}he goal of this study is to investigate possible origins of these features, by impact processes (shock metamorphic effects, impact-induced hydrothermal systems) or postimpact surficial processes (erosion, weathering). {T}he origin of these features is discussed here based on field observations, ground-based radiometric measurements, and first cosmogenic nuclide analyses ({B}e-10). {T}he data indicate that the rim and outer ridge were eroded more rapidly than the rest of the impact structure. {A}ccordingly, the downward advance of the weathering fronts in the annular moat, after ejecta emplacement, are responsible for leaching of {K} from the lateritic residual observed at the surface. {T}he {B}osumtwi impact structure is, therefore, a valuable natural laboratory to investigate the factors controlling erosion and weathering processes in the {A}shanti belt since impact 1 {M}a ago. {S}imulations of vertical profiles of {B}e-10 concentration further constrain local variations of the erosion rate. {I}n light of this study, circular {K} anomalies in radiometric surveys might be indicative of potential impact structures in tropical regions.},
  keywords = {{GHANA}},
  booktitle = {},
  journal = {{M}eteoritics and {P}lanetary {S}cience},
  volume = {52},
  numero = {},
  pages = {702--729},
  ISSN = {1086-9379},
  year = {2022},
  DOI = {10.1111/maps.13788},
  URL = {https://www.documentation.ird.fr/hor/fdi:010084404},
}