url:csmonitor.com

Simplicissimus @simplicissimus 14/05/2016

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Florida sinkhole archeological site recasts ’peopling of the Americas’ narrative - CSMonitor.com
▻http://www.csmonitor.com/Science/2016/0513/Florida-sinkhole-archeological-site-recasts-peopling-of-the-Americas-narr
Deep in an underwater sinkhole in a river in Florida, archeologists have found the remains of a prehistoric population of humans that lived in the region some 14,550 years ago. Stone tools, mastodon bones with distinct cut marks, and mastodon dung hold enticing clues into the lives of these early Americans and the megafauna around them. Those new findings are reported in a paper published Friday in the journal Science Advances.
Today these findings are accepted as adding to the early prehistory of the Americas, but that wasn’t the case for artifacts unearthed from the same site just decades ago.

Simplicissimus @simplicissimus
- Simplicissimus @simplicissimus 14/05/2016
  
  Pre-Clovis occupation 14,550 years ago at the Page-Ladson site, Florida, and the peopling of the Americas | Science Advances
  ▻http://advances.sciencemag.org/content/2/5/e1600375
  Abstract
  Stone tools and mastodon bones occur in an undisturbed geological context at the Page-Ladson site, Florida. Seventy-one radiocarbon ages show that ~14,550 calendar years ago (cal yr B.P.), people butchered or scavenged a mastodon next to a pond in a bedrock sinkhole within the Aucilla River. This occupation surface was buried by ~4 m of sediment during the late Pleistocene marine transgression, which also left the site submerged. Sporormiella and other proxy evidence from the sediments indicate that hunter-gatherers along the Gulf Coastal Plain coexisted with and utilized megafauna for ~2000 years before these animals became extinct at ~12,600 cal yr B.P. Page-Ladson expands our understanding of the earliest colonizers of the Americas and human-megafauna interaction before extinction.
  http://d3a5ak6v9sb99l.cloudfront.net/content/advances/2/5/e1600375/F2.large.jpg
  
  Fig. 2 Stratigraphy of excavation units at the Page-Ladson site displaying pre-Clovis artifacts and radiocarbon ages.
  (A) Artifact 12209-a. (B) Artifact 12209-b. (C) Artifact 12242-1. (D) Artifact 12068-2. (E) Artifact 12068-1. (F) Artifact 12080-1. (A) to (E) are flakes; (D) shows evidence of use. (F) is a biface. (G) 2014 wall profiles showing stratigraphy, locations of artifact finds, and location of radiocarbon samples. (H) 2013 wall profiles showing stratigraphy, locations of artifact finds, and location of radiocarbon samples. For (G) and (H), white dots represent locations and ages of radiocarbon samples collected from profiles. Purple dots and text represent radiocarbon ages collected from within units, plotted with correct elevation, and northing or easting. Red triangles show locations of artifacts collected from within units, plotted with correct elevation, and northing or easting. Open red circle shows approximate location of artifacts found in the screen. Trees in the profile are represented by dark brown. Note that although the biface appears as if it were found in the middle of a tree, the tree only occurs in the south wall profile and does not extend into the excavation unit where the biface was found.
  
  Simplicissimus @simplicissimus
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Fil @fil 13/05/2013

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Google Earth Engine unveils how Earth has altered - CSMonitor.com
▻http://www.csmonitor.com/Science/2013/0510/Google-Earth-Engine-unveils-how-Earth-has-altered
Google Earth Engine, a global, zoomable timelapse map that allows you to witness how humans have altered the surface of the Earth since 1984.
▻http://www.youtube.com/watch?feature=player_embedded&v=ZXj1bwjVrp8
#cartographie #environnement #satellite

Fil @fil
- odilon @odilon CC BY-NC-ND 13/05/2013
  
  et ici
  ▻http://seenthis.net/messages/137385
  
  odilon @odilon CC BY-NC-ND
- Fil @fil 13/05/2013
  
  ça t’apprendra à pas avoir mis de lien vidéo
  
  Fil @fil
- odilon @odilon CC BY-NC-ND 13/05/2013
  
  Ben, je ne sais pas intégrer les vidéos du site :(
  
  odilon @odilon CC BY-NC-ND
- Fil @fil 13/05/2013
  
  ok : il faut cliquer sur le bouton « youtube » de la vidéo, et copier ensuite le lien de la page youtube que ça devra(it) t’avoir ouvert
  
  Fil @fil
- odilon @odilon CC BY-NC-ND 13/05/2013
  
  ah mais ce ne sont pas des des vidéos youtube justement (avec youtube je sais faire)
  
  odilon @odilon CC BY-NC-ND
- tbn @thibnton PUBLIC DOMAIN 13/05/2013
  
  et aussi @lydie ►http://seenthis.net/messages/137128 #google_earth
  
  tbn @thibnton PUBLIC DOMAIN
- Fil @fil 13/05/2013
  
  hmmm ok alors :)
  
  Fil @fil
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