@inproceedings{PAR00003021,
  title = {{O}nocerane {I} witnesses to dry climatic phases at the end of {L}ast {G}lacial {M}aximum and during the {Y}ounger {D}ryas in {N}orthern {B}razil},
  author = {{J}acob, {J}. and {D}isnar, {J}.{R}. and {B}oussafir, {M}. and {L}edru, {M}arie-{P}ierre and {S}ifeddine, {A}bdelfettah and {S}padano {A}lbuquerque, {A}.{L}. and {T}urcq, {B}runo},
  editor = {},
  language = {{ENG}},
  abstract = {{O}nocerane-related compounds are very uncommon molecules that are seldom encountered in the plant kingdom and even more rarely in sediments. {I}n living plants, onoceranoids have been isolated from taxa as diverse as ferns, club mosses and {F}abaceae. {I}n this latter, onocerin (onoceranediol) is supposed to render the roots water-impermeable and to allow the plants belonging to this genus to colonize water-depleted media. {I}n sediments, onoceranes have been observed up to the {C}arboniferous but mainly in post-{C}retaceous series always deposited in continental settings (lacustrine, intramontane basins, lagoonal or brackish contexts). {W}e here report on the first occurrence of onocerane {I} in {L}ate {P}leistocene and {Q}uaternary sediments, collected in a lake located almost under the {E}quator ({L}agoa do {C}a{\c{c}}o, {NE} {B}razil). {T}he comparison of onocerane {I} abundance with palynological results all through the last 20,000 years allow us to exclude ferns and club mosses as possible producers of onocerane in this setting. {O}nocerane {I} is only found in significant amounts in two distinct sedimentary intervals: the first, rapidly deposited at the end of {L}ast {G}lacial {M}aximum (c.a. 21,000 cal yrs {B}.{P}.) and the second during the {Y}ounger {D}ryas (between 13,000 and 12,000 cal yrs {B}.{P}.) (figure 1). {T}hese two periods are both documented as having been dryer than those prevailing presently. {T}herefore, the presence of onocerane {I} in the sediments deposited during these two intervals testimonies to the development of plants adapted to water-deficient environments. {N}o evidence of a possible precursor can be deciphered from palynological results, probably due to the poor conservation of the pollen of these plants.},
  keywords = {{BRESIL}},
  numero = {},
  pages = {36  multigr.},
  booktitle = {},
  year = {2003},
  URL = {https://www.documentation.ird.fr/hor/{PAR}00003021},
}