Tafkin Yoa

Tafkuna Yoa shine mafi shahara, kuma na biyu mafi girma, na Lakes na Ounianga, jerin Lakes a cikin Yankin Borkou-Ennedi-Tibesti na arewa maso gabashin Chadi. Tana cikin Ounianga Kebir kimanin kilomita 40 a yammacin Ounianga Sarir . Wadannan tabkuna sune ragowar tafkin da ya fi girma wanda ya mamaye wannan kwandon a lokacin Rashin Afirka, wanda ya kasance daga kimanin shekaru 15,000 zuwa 5,500 kafin yanzu. A halin yanzu akwai tabkuna 15 a cikin kwandon tare da jimlar yanki na kimanin kilomita 20 (12 murabba'in. Canjin yanayi Tafkin Yoa kwanan nan ya zama mai ban sha'awa a cikin nazarin yanayin yanayi na duniya lokacin da ƙungiyar da Stefan Kröpelin, na Jami'ar Cologne, ke jagoranta, ta dawo da ainihin laka daga kasan tafkin. Saboda Tafkin Yoa ya kasance a kai a kai tun lokacin Ruwa ruwansa ya kare turɓaya da aka tara a kasa daga rushewa da warwatsewa. Bayan nazarin pollen da aka adana a cikin core, Kröpelin da abokan aikinsa sun kammala cewa canjin daga gandun daji zuwa hamada a yankin Lake Yoa ya faru a hankali, tare da lokutan shiga tsakani na scrubland da ciyawa kafin farawar yanayin hamada. Wannan kammalawa ya bambanta da aikin da Peter deMenocal na Jami'ar Columbia da abokan aiki suka yi, wadanda a cikin 2000 suka hako wani core na teku sediment daga yammacin gabar Mauritania. Saboda matakan ƙura a cikin wannan core, deMenocal da abokan aikinsa sun kammala cewa yanayin hamada ya zo da sauri, a cikin 'yan ƙarni. Bambance-bambance tsakanin waɗannan asusun biyu ba abin mamaki ba ne saboda bambance-bambancen da ke cikin bayanan da aka bincika. Babban teku yana wakiltar abin da ke da mahimmanci binciken taro na duk yankin arewacin ƙasar Afirka yayin da bayanan Lake Yoa za su bincika musamman yanayin a yankunan kudu da yammacinsa, wanda ya ba da kayan aiki ga iskar kasuwanci ta Holocene kafin su haye Lake Yoa. Yana yiwuwa duka biyun, arewacin Afirka ya zama da sauri kuma gabaɗaya ya bushe, kuma cewa, a takamaiman yankuna tsarin hamada ya motsa ta hanyar jerin sauye-sauyen muhalli. (Ranson, 2008). Rahoton na biyu kuma bai yi la'akari da nisan yankin Lake Yoa daga Tekun Atlantika ba, sama da kilomita 2,000 (1,000 . Manazarta