http://www.thestar.com/sciencetech/article/213967
May 15, 2007 07:09 AM
TOBY MUSE
Associated Press
"BOGOTA, Colombia - There's a new chirp in the forest but it may be choked by the slashing and burning of trees by coca farmers, researchers said. The species belongs to the Puffleg genus, which appear to have "little cotton balls above their legs," said Luis Mazariegos-Hurtado, who has spent 30 years documenting hummingbirds and founded the Colombian Hummingbird Conservancy."
...still no word on bin Laden.
~Thanks SNL ...just a little joke to start off a new post.
"If the findings, published in
Quaternary Science Reviews, are correct, climate change put paid to a extraordinarily durable creature. The Neanderthals survived in the Iberian peninsula long after those living elsewhere in Europe had died out. Squat, powerful hunters, they appear in the fossil record about 350,000 years ago and, at their peak, dominated much of the northern hemisphere, from Britain in the west to Israel in the south and Uzbekistan in the east. Southern Iberia served as a habitat for the last of them because it provided
shelter from the worst of the frequent, rapid changes in climate which hit a peak 30,000 years ago.
But eventually, the change in climate appears to have become too pronounced - even for them. It seems to have caused a drought, placing pressure on the last surviving Neanderthals by reducing their supplies of fresh water and killing off the animals they hunted.
The event was the most severe the region had seen for 250,000 years."
So then....note: Marine productivity has been established using Baexcess (Barium excess?), and has a strong link with climatic/oceanographic oscillations, with greatest values during cold events such as H1 and YD [Heinrich 1, Younger Dryas].-from:
Quaternary Science Reviews Volume 26, Issues 7-8, April 2007, Pages 836-852
"Paleoclimate records from the western Mediterranean have been used to further understand the
role of climatic changes in the replacement of archaic human populations inhabiting South Iberia. Marine sediments from the Balearic basin (ODP Site 975) was analysed at high resolution to obtain both geochemical and mineralogical data. These data were compared with climate records from nearby areas. Baexcces was used to characterize marine productivity and then related to climatic variability. Since variations in productivity were the consequence of climatic oscillations, climate/productivity events have been established.
Sedimentary regime, primary marine productivity and oxygen conditions at the time of population replacement were reconstructed by means of a multiproxy approach. Climatic/oceanographic variations correlate well with Homo spatial and occupational patterns in Southern Iberia. It was found that low ventilation (U/Th), high river supply (Mg/Al), low aridity (Zr/Al) and low values of Baexcess coefficient of variation, may be linked with Neanderthal hospitable conditions. We attempt to support recent findings which claim that Neanderthals populations continued to inhabit southern Iberia between 30 and 28 ky cal BP and that this persistence was due to the specific characteristics of South Iberian climatic refugia. Comparisons of our data with other marine and continental records appear to indicate that conditions in South Iberia were highly inhospitable at 24 ky cal BP. Thus, it is proposed that the final disappearance of Neanderthals in this region could be linked with these extreme conditions.
If climate did play an important role in the extinction of the Neanderthals and the expansion of the Moderns, some of the hypotheses regarding this process are likely to be corroborated. Climatic variability during cold periods probably acted as a "territory cleanser", thus favouring a subsequent colonization by Moderns. Stable "frontiers" could be expected when hospitable conditions prevailed. It is likely that the most important episodes of replacement took place over relatively short periods, coinciding with adverse climatic conditions. For as yet unknown reasons, these areas were apparently more successfully recolonized by Moderns during subsequent periods of hospitable conditions. Therefore, the temporal-spatial location of the outcrops may play a major role in confirming climatic influence. North Africa also deserves particular attention, since chronological patterns could have been similar and disappearances may have been simultaneous.
5. Conclusions
Geochemical and mineralogical proxies show evidence of significant paleoenviromental changes in the WMS at time of Neanderthal extinction. Comparisons of different records suggest that from 250 ky down to 24 ky BP, the most extreme conditions in WMS were reached between 24 and 25 ky cal BP. Climatic changes apparently affected the number and distribution of Modern and Neanderthal sites in southern Iberia. Especially high values in millennial Baexcess var. (BA events) are well correlated with some of the changes in the number of sites and in replacements of industries. Cold, arid and highly variable conditions could be associated with the penetration and presence of Modern industries. This suggests that climatic variability during cold periods in the non-analogue MIS 3 could have affected Neanderthal populations, thus promoting weakness, isolation or extinction. Indeed, the definitive disappearance of Neanderthals could be linked with the unfavourable conditions during BA1 (22.5-25.5 ky cal BP). However, in order to further clarify the causes of this disappearance, more in-depth studies should be carried out on outcrops in southern Iberia and North
Africa."
I went on to find all kinds of neat stuff about glaciers, solar variance, Beringia, sea levels, C3/C4 in S.Africa, and volcanoes i.r.t. climate; but just....note: The relative abundance of the polar species Neogloboquadrina pachyderma sinistral is commonly used as a palaeo-indicator of polar waters, dominating the planktonic assemblage in waters of summer SST <8 degrees C. -from:
Quaternary Science Reviews
Volume 26, Issues 7-8, April 2007, Pages 862-875
"Given that this interval is coincident with the final delivery of IRD (IceRaftDebris) to the core site during the Younger Dryas (high % N. pachyderma sin.) we consider this ash horizon to be the Vedde Ash, most recently dated as 12.1 ka BP within the GISPII ice core."
~Wow, GISP O18 & N.Pachyderma are at all time highs for past 60Kya (following the Vedde Ash event [12.5Kya?])!
Cool record of volcanic debris (w/ sharp thin peak at about 26.5kya). H2 is very significant at about 24.2kya;Does anyone know of a volcanic event around 26.5Kya?I saw a tall thin peak in debris records from core samples.
It was probably in N. American or around the Neanderthal's presumed range (Euro/W.Asia).
Thanks for the journey.
~Samwik
