@article{fdi:010027313,
  title = {{L}ast glacial maximum lacustrine and fluviatile formations in the {T}ibesti and other {S}aharan mountains and large-scale climatic teleconnections linked to the activity of the subtropical jet stream},
  author = {{M}aley, {J}ean},
  editor = {},
  language = {{ENG}},
  abstract = {{I}n the mountains of the central {S}ahara (lat ca. 20° to 22°{N}, long 16° to 19°{E}) and particularly in the {T}ibesti mountains, important lacustrine formations developed during the late {P}leistocene, primarily during the {L}ast {G}lacial {M}aximum ({LGM}). {T}wo main phases, separated by a brief regression, intervened between ca. 20,000 and 15,500 {BP}, and between 15,000 and 12,500 {BP}. {P}ollen analyses were carried out on four samples of this formation. {T}he high lacustrine levels were associated to both important precipitations and a reduced evaporation linked to lower temperatures. {S}imilar lacustrine deposits were found in the {D}jebel {M}arra in the south of the {S}ahara. {I}n the mountains of the central and eastern {S}ahara, during the same period and until the middle {H}olocene, the '{M}iddle {T}errace' {F}ormation was deposited in the river valleys of the {T}ibesti, {H}oggar, {A}ir and the {R}ed {S}ea {H}ills. {S}ince the southern headwaters of the {N}ile were dry from ca. 20,000 to 12,500 {BP}, the fluviatile sediments deposited in the {N}ile valley in {N}ubia may have resulted almost entirely from the numerous wadis flowing from the {R}ed {S}ea {H}ills. {T}he rainfalls which fed these lacustrine and fluviatile formations were related to the {T}ropical {D}epressions which are formed in the southern part of the westerlies and are linked to the activity of the {S}ubtropical {J}et {S}tream ({STJ}), whose path remained over the central {S}ahara from 20,000 {BP} to the early {H}olocene. {I}n the {R}ocky {M}ountains of the western {US}, the palaeolakes {L}ahontan and {B}onneville were very large during the {LGM} and the main fluctuations exhibit similar chronology to that of the {S}aharan mountains. {B}roecker [{B}roecker, {W}.{S}., 1994. {M}assive iceberg discharges as triggers for global climate change. {N}ature 372, 421-424] estimates that these two large {U}.{S}. wet events between ca. 20,000-15,500 {BP} and ca. 15,000-12,500 {BP} may have been an indirect result of two large ice surges in the {N}orth {A}tlantic, related to {H}einrich layers 1 and 2. {W}e can assume, however, that the similar climatic variation of the {R}ocky {M}ountains and the central and eastern {S}aharan mountains was also a result of the activity of the {STJ} all along its path, which marks the boundary between the polar and tropical circulations. {STJ} activity can apparently produce long-distance climatic teleconnections. {D}uring the {LGM} similar teleconnections also existed in the {S}outhern {H}emisphere between {S}outh {A}frica and {A}ustralia. {T}he {T}ropical {D}epressions result from the interaction of polar troughs and the influx of humid equatorial air forming transversal cloud bands. {T}he large increase in the intensity of atmospheric circulation during the {LGM} was responsible for a large increase in {T}ropical {D}epressions in both hemispheres.},
  keywords = {{PALEOCLIMAT} ; {SEDIMENTATION} {LACUSTRE} ; {POLLEN} ; {SEDIMENTATION} {FLUVIATILE} ; {COURANT} {MARIN} ; {HOLOCENE} ; {CHANGEMENT} {CLIMATIQUE} ; {SAHARA} ; {TIBESTI}},
  booktitle = {},
  journal = {{G}lobal and {P}lanetary {C}hange},
  volume = {26},
  numero = {1-3},
  pages = {121--136},
  ISSN = {0921-8181},
  year = {2000},
  DOI = {10.1016/{S}0921-8181(00)00039-4},
  URL = {https://www.documentation.ird.fr/hor/fdi:010027313},
}