Precession-forced changes in South West African vegetation during Marine Isotope Stages 101–100 (∼2.56–2.51 Ma)

Northeast African vegetation change over 12 m.y.

“…These broad trends align with the progressive expansion of Northern Hemisphere glaciations after 2.7 Ma (Lisiecki and Raymo, 2005), supporting a role for the high latitudes in driving the tropical vegetation changes during the Pleistocene (Dupont, 2011;Schefuss et al, 2011). However, local insolation forcing (precession dominated) has also been implicated in tropical African vegetation changes (Denison et al, 2005;Dupont, 2011). We here confi rm our earlier report (Feakins et al, 2005) that northeast African environmental variability began well before the onset of Northern Hemisphere glaciations, as early as 4.3 Ma.…”

Pressure Dependence in the Methyl Vinyl Ketone+OH and Methacrolein+OH Oxidation Reactions: An Electronic Structure Study

“…Compound‐specific δ 13 C analysis of refractory n ‐alkanes of exclusively higher plant origin avoids this problem, and has been shown to record C 3 and C 4 species differences with fidelity in modern and geological materials (e.g. Collister et al ., 1994; Schefuss et al ., 2003; Rommerskirchen et al ., 2003; Denison et al ., 2005). Collister et al .…”

High‐frequency climate linkages between the North Atlantic and the Mediterranean during marine oxygen isotope stage 100 (MIS100)

“…These records reveal that the observed increase in the δ 13 C benthos record which we linked to MIS100.3 is accompanied by wetter climate conditions in northwest Africa and decreased NE trade wind strength. Further evidence that the precession cycle may have played a critical role on the strength of the trade winds during MIS100.3 comes from the n‐alkane δ 13 C record of the South Atlantic ODP Site 1083 [ Denison et al , 2005]. This Southern Hemisphere midlatitude record reflects relatively dry climate conditions (i.e., high contributions of C 4 plants and a high water stress of C 3 plants) during insolation cycle i‐244, which clearly point to an opposite precession‐related signal during i‐244 as observed in northwest Africa.…”

“…This Southern Hemisphere midlatitude record reflects relatively dry climate conditions (i.e., high contributions of C 4 plants and a high water stress of C 3 plants) during insolation cycle i‐244, which clearly point to an opposite precession‐related signal during i‐244 as observed in northwest Africa. It was suggested that these climate conditions are triggered by reduced monsoonal precipitation in southwest Africa and are independent of glacial‐interglacial variability [ Denison et al , 2005].…”