Homo sapiens na zamani sun shiga cikin ɗimbin sauye-sauye na yanayin muhalli, amma yana da wahala a gano asali ko farkon sakamakon waɗannan halayen.Archaeology, geochronology, geomorphology, da paleoenvironmental data from arewacin Malawi sun rubuta canjin alakar dake tsakanin kasancewar ma'aikatan abinci, ƙungiyar muhalli, da ƙirƙirar fanfo a cikin Late Pleistocene.Bayan kimanin karni na 20, an kafa wani tsari mai yawa na kayan tarihi na Mesolithic da magoya bayan alluvial.Shekaru 92,000 da suka gabata, a cikin yanayin yanayin yanayin yanayi, babu wani misali a cikin rikodin shekaru 500,000 da suka gabata.Bayanai na binciken kayan tarihi da babban bincike na daidaitawa sun nuna cewa gobarar da mutum ya yi ta farko ya sassauta ƙuntatawa na yanayi kan ƙonewa, yana shafar tsarin ciyayi da zaizayar ƙasa.Wannan, haɗe da sauye-sauyen hazo da ke haifar da yanayi, daga ƙarshe ya haifar da sauye-sauyen yanayin muhalli zuwa farkon wuri na wucin gadi kafin noma.
’Yan Adam na zamani masu ƙarfi ne masu haɓaka canjin yanayin muhalli.Tsawon shekaru dubbai, sun canza yanayi sosai kuma da gangan, suna haifar da muhawara game da yaushe da kuma yadda tsarin halitta na farko da ɗan adam ya mamaye ya fito (1).Ƙarin shaidun archaeological da na ƙabilanci sun nuna cewa akwai adadi mai yawa na hulɗar hulɗar da ke tsakanin masu neman abinci da muhallinsu, wanda ke nuna cewa waɗannan dabi'un sune tushen juyin halittar mu (2-4).Bayanan burbushin halittu da kwayoyin halitta sun nuna cewa Homo sapiens ya wanzu a Afirka kimanin shekaru 315,000 da suka wuce (ka).Bayanai na archaeological sun nuna cewa rikice-rikicen dabi'un da ke faruwa a cikin nahiyar ya karu sosai a baya kusan 300 zuwa 200 ka spans.Ƙarshen Pleistocene (Chibanian) (5).Tun fitowar mu a matsayin nau'i, mutane sun fara dogara ga ƙirƙira fasaha, shirye-shiryen yanayi, da hadaddun haɗin gwiwar zamantakewa don bunƙasa.Waɗannan halayen suna ba mu damar yin amfani da yanayin da ba a taɓa zama ba ko matsananciyar yanayi da albarkatu, don haka a yau mutane ne kawai nau'in dabba na duniya (6).Wuta ta taka muhimmiyar rawa a wannan sauyi (7).
Samfuran halittu sun nuna cewa ana iya samun dacewa da dafaffen abinci aƙalla shekaru miliyan 2 da suka gabata, amma ba sai ƙarshen Pleistocene ta Tsakiya ba cewa shaidar binciken kayan tarihi na al'ada na sarrafa gobara ta bayyana (8).Tushen teku tare da bayanan ƙura daga babban yanki na nahiyar Afirka ya nuna cewa a cikin miliyoyin shekaru da suka gabata, kololuwar carbon ya bayyana bayan kusan 400 ka, galibi a lokacin canji daga interglacial zuwa lokacin glacial, amma kuma ya faru a lokacin. Hoton (9).Wannan ya nuna cewa kafin kusan 400 ka, gobara a yankin kudu da hamadar sahara ba ta zama ruwan dare ba, kuma gudunmuwar mutane na da muhimmanci a cikin Holocene (9).Wuta kayan aiki ne da makiyaya ke amfani da shi a ko'ina cikin Holocene don noma da kula da filayen ciyawa (10).Koyaya, gano asali da tasirin muhalli na amfani da wuta ta masu farauta a farkon Pleistocene ya fi rikitarwa (11).
Wuta ana kiranta kayan aikin injiniya don sarrafa albarkatu a cikin ilimin ƙabilanci da ilimin kimiya na kayan tarihi, gami da inganta dawowar rayuwa ko gyara albarkatun ƙasa.Waɗannan ayyukan yawanci suna da alaƙa da tsara jama'a kuma suna buƙatar ilimin muhalli da yawa (2, 12, 13).Wuta mai girman ƙasa tana ba masu farauta damar korar ganima, sarrafa kwari, da haɓaka yawan amfanin gonaki (2).Wuta a wurin tana haɓaka dafa abinci, dumama, kariyar mafarauta, da haɗin kan zamantakewa (14).Duk da haka, gwargwadon yadda gobarar mafarauci za ta iya sake fasalin abubuwan da ke cikin shimfidar wuri, kamar tsarin al'ummar muhalli da kuma yanayin yanayin yanayi, yana da ma'ana sosai (15, 16).
Ba tare da tsoffin bayanan archaeological da geomorphological da ci gaba da bayanan muhalli daga wurare da yawa ba, fahimtar haɓakar sauye-sauyen yanayin muhalli da ɗan adam ke haifar da matsala.Rubuce-rubucen ajiyar tafkin na dogon lokaci daga Babban Rift Valley a Kudancin Afirka, haɗe da tsoffin bayanan kayan tarihi a yankin, sun sa ya zama wurin bincika tasirin muhallin da Pleistocene ya haifar.Anan, muna bayar da rahoto game da ilimin kimiya na kayan tarihi da kuma yanayin ƙasa na wani faffadan shimfidar zamanin Dutse a kudu maso tsakiyar Afirka.Sa'an nan, mun haɗa shi tare da bayanan muhalli mai faɗi> 600 ka don tantance farkon shaidar haɗin gwiwa na halayen ɗan adam da sauyin yanayin muhalli a cikin mahallin gobarar da mutum ya yi.
Mun bayar da iyakacin shekarun da ba a ba da rahoton ba ga gadon Chitimwe a gundumar Karonga, wanda ke arewacin ƙarshen arewacin Malawi a kudancin Rift Valley na Afirka (Hoto 1) (17).Wadannan gadaje na kunshe ne da jan karfen da ba a taba gani ba da kuma ruwan kogi, wanda ya kai kimanin murabba'in kilomita 83, dauke da miliyoyin kayayyakin dutse, amma babu sauran ragowar kwayoyin halitta, kamar kasusuwa (Karin rubutu) (18).Bayanin haskenmu mai kyan gani (OSL) daga rikodin Duniya (Hoto 2 da Tables S1 zuwa S3) sun gyara shekarun gadon Chitimwe zuwa Late Pleistocene, kuma mafi tsufa shekarun kunna fan alluvial da binne shekarun dutse kusan 92 ka ( 18, 19).Layin alluvial da kogin Chitimwe ya rufe tafkuna da koguna na Layer Pliocene-Pleistocene Chiwondo daga rashin daidaituwa mara kyau (17).Wadannan adibas ɗin suna cikin ɓangarorin kuskure tare da gefen tafkin.Tsarin su yana nuna hulɗar tsakanin jujjuyawar matakin tafkin da kurakurai masu aiki da suka shiga cikin Pliocene (17).Kodayake aikin tectonic na iya shafar yanayin yanayin yanki da gangaren piedmont na dogon lokaci, aikin kuskure a wannan yanki na iya raguwa tun daga Tsakiyar Pleistocene (20).Bayan ~ 800 ka kuma har zuwa jim kadan bayan 100 ka, yanayin ruwa na tafkin Malawi ya fi jan hankalin yanayi (21).Saboda haka, ba ɗayan waɗannan ba shine kawai bayanin samuwar magoya baya a cikin Late Pleistocene (22).
(A) Matsayin tashar Afirka dangane da hazo na zamani (alama);blue ya fi ruwa, ja kuma ya fi bushewa (73);akwatin da ke hagu yana nuna tafkin Malawi da kewaye MAL05-2A da MAL05-1B Wurin da ke cikin /1C core (dige mai ruwan hoda), inda aka haskaka yankin Karonga a matsayin koren zane, kuma an nuna wurin da gadon Luchamange yake. a matsayin farin akwati.(B) Yankin arewacin Malawi basin, yana nuna hoton tsaunin tuddai dangane da ainihin MAL05-2A, ragowar Chitimwe gado (faci mai launin ruwan kasa) da wurin tono wurin aikin Malawi Early Mesolithic (MEMSAP) (digon rawaya));CHA, Chaminade;MGD, ƙauyen Mwanganda;NGA, Ngara;SS, Sadara ta Kudu;VIN, hoton ɗakin karatu na adabi;WW, Beluga.
Shekarun cibiyar OSL (layin ja) da kewayon kuskure na 1-σ (25% launin toka), duk shekarun OSL masu alaƙa da abin da ya faru a cikin kayan tarihi a Karonga.Shekaru dangane da bayanan 125 da suka gabata ya nuna (A) kididdigar yawan kernel na duk shekarun OSL daga tsattsauran ra'ayi na fan, yana nuna tarin ruwa mai tsafta (cyan), da sake gina matakin ruwa ta lake bisa la'akari da mahimman ƙimar abubuwan ruwa (PCA). burbushin halittu da ma'adanai na gaske (21) (blue) daga ainihin MAL05-1B/1C.(B) Daga MAL05-1B/1C core (baƙar fata, ƙimar kusa da 7000 tare da alamar alama) da MAL05-2A core (launin toka), ƙididdige macromolecular carbon a kowace gram wanda aka daidaita ta hanyar ƙimar lalata.(C) Ma'aunin wadatar nau'in Margalef (Dmg) daga MAL05-1B/1C core fossil pollen.(D) Kashi na fossil pollen daga Compositae, Miombo woodland da Olea europaea, da (E) Kashi na fossil pollen daga Poaceae da Podocarpus.Duk bayanan pollen sun fito ne daga ainihin MAL05-1B/1C.Lambobin da ke saman suna komawa ga samfuran OSL guda ɗaya dalla-dalla a cikin Tables S1 zuwa S3.Bambance-bambancen samun bayanai da ƙuduri shine saboda tazarar samfuri daban-daban da wadatar kayan aiki a cikin ainihin.Hoto S9 yana nuna bayanan macro carbon guda biyu waɗanda aka canza zuwa z-scores.
(Chitimwe) Ana nuna kwanciyar hankali da kwanciyar hankali bayan samar da fanfo ta hanyar samuwar jajayen ƙasa da carbonates masu samar da ƙasa, waɗanda ke rufe ɓangarorin fanni na duka yankin binciken (Ƙarin rubutu da Table S4).Samuwar magoya bayan Late Pleistocene alluvial a cikin tafkin Malawi Basin bai iyakance ga yankin Karonga ba.Kimanin kilomita 320 kudu maso gabas da Mozambique, bayanan zurfin bayanan duniya na cosmogenic nuclide na 26Al da 10Be yana iyakance samuwar gadon Luchamange na ƙasa ja ja zuwa 119 zuwa 27 ka (23).Wannan ƙayyadaddun ƙayyadaddun shekarun ya yi daidai da tarihin tarihin mu na OSL na yammacin Tekun Malawi Basin kuma yana nuna haɓakar magoya bayan yanki a cikin Late Pleistocene.Wannan yana goyan bayan bayanan daga rikodin rikodin tafkin, wanda ke nuna cewa mafi girman ƙwayar cuta yana tare da kusan 240 ka, wanda ke da ƙima na musamman a ca.130 da 85 ka (karin rubutu) (21).
Shaida ta farko na zaman ɗan adam a wannan yanki yana da alaƙa da ɓarnar Chitimwe da aka gano a ~92 ± 7 ka.Wannan sakamakon ya dogara ne akan 605 m3 na ɓangarorin da aka tono daga 14 sub-centimeter sararin samaniya sarrafa kayan tarihi na archaeological da 147 m3 na sediments daga 46 gwajin gwaje-gwaje na archaeological, sarrafawa a tsaye zuwa 20 cm kuma a kwance ana sarrafa shi zuwa mita 2 (Ƙarin rubutu da Figures S1 zuwa S3) Bugu da kari, mun kuma yi bincike a kan kilomita 147.5, mun tsara ramukan gwajin yanayin kasa guda 40, mun kuma yi nazarin kayayyakin al'adu sama da 38,000 daga 60 daga cikinsu (Tables S5 da S6) (18).Wadannan faffadan bincike da bincike sun nuna cewa duk da cewa mutanen da da suka hada da mutanen farko na zamani mai yiwuwa sun rayu a yankin kimanin shekaru 92 da suka gabata, tarin magudanar ruwa da ke da nasaba da tasowa da kuma tabbatar da tabkin Malawi bai adana bayanan archaeological ba har sai da ya samar da gadon Chitimwe.
Bayanan archaeological sun goyi bayan ra'ayin cewa a cikin ƙarshen Quaternary, faɗaɗa mai siffar fan da ayyukan ɗan adam a arewacin Malawi ya wanzu da yawa, kuma kayan tarihi na al'adu na nau'ikan sauran sassan Afirka ne masu alaƙa da ɗan adam na zamani na farko.Yawancin kayan tarihi an yi su ne da dutsen quartzite ko ma'adini na kogin, tare da radial, Levallois, dandamali da raguwar ainihin bazuwar (Hoto S4).Abubuwan da aka gano na ilimin dabi'a an danganta su ga Mesolithic Age (MSA) - takamaiman nau'in fasaha na Levallois, wanda ya kasance aƙalla kusan 315 a Afirka ya zuwa yanzu (24).Babban gadon Chitimwe yana dawwama har zuwa farkon Holocene, wanda ya ƙunshi abubuwan da ba a iya rarrabawa a ƙarshen zamanin Dutse ba, kuma an gano yana da alaƙa da mafarauta Pleistocene da Holocene a duk faɗin Afirka.Sabanin haka, al'adun kayan aikin dutse (kamar manyan kayan aikin yankan) yawanci suna hade da Pleistocene na Farko na Tsakiya ba su da yawa.Inda waɗannan suka faru, an same su a cikin abubuwan da ke ɗauke da MSA a cikin ƙarshen Pleistocene, ba a farkon matakan ajiya ba (Table S4) (18).Kodayake rukunin yanar gizon ya kasance a ~92 ka, mafi yawan lokacin wakilcin ayyukan ɗan adam da ƙaddamarwar fan na alluvial ya faru bayan ~ 70 ka, da tsarar tsarar shekarun OSL (Hoto 2).Mun tabbatar da wannan ƙirar tare da 25 da aka buga da 50 waɗanda ba a buga ba a baya OSL shekaru (Hoto 2 da Tables S1 zuwa S3).Wadannan suna nuna cewa daga cikin jimlar shekarun 75, 70 an dawo dasu daga sediments bayan kimanin 70 ka.Hoto na 2 yana nuna shekaru 40 da ke da alaƙa da kayan tarihi na MSA a cikin wurin, dangane da manyan alamomin yanayin muhalli da aka buga daga tsakiyar babban kwano na MAL05-1B/1C (25) da cibiyar MAL05-2A ta arewa da ba a buga a baya ba.Gawayi (kusa da fan wanda ke samar da shekarun OSL).
Yin amfani da sabbin bayanai daga tono kayan tarihi na phytoliths da micromorphology na ƙasa, da kuma bayanan jama'a kan fossil pollen, manyan gawayi, burbushin ruwa da ma'adanai na gaske daga ainihin aikin hakowa tafkin Malawi, mun sake gina dangantakar ɗan adam ta MSA da tafkin Malawi.Shagaltar da yanayi da yanayin muhalli na lokaci guda (21).Wakilan biyu na ƙarshe sune tushen tushen sake gina zurfin tafkin dangi wanda ya dawo sama da 1200 ka (21), kuma an daidaita su da samfuran pollen da macrocarbon waɗanda aka tattara daga wuri ɗaya a cikin ainihin ~ 636 ka (25) a baya. .An tattara mafi tsayin muryoyi (MAL05-1B da MAL05-1C; 381 da 90 m bi da bi) kusan kilomita 100 kudu maso gabas na yankin aikin binciken kayan tarihi.An tattara gajeriyar cibiya (MAL05-2A; 41 m) kimanin kilomita 25 gabas da Kogin Rukulu ta Arewa (Hoto na 1).Babban MAL05-2A yana nuna yanayin yanayin muhalli na ƙasa a cikin yankin Kalunga, yayin da MAL05-1B/1C core ba ya karɓar shigarwar kogin kai tsaye daga Kalunga, don haka zai iya nuna yanayin yanki mafi kyau.
Matsakaicin adadin da aka rubuta a cikin MAL05-1B/1C hadaddiyar giyar rawar soja ya fara daga 240 ka kuma ya ƙaru daga matsakaicin ƙimar 0.24 na dogon lokaci zuwa 0.88 m/ka (Hoto S5).Haɓakawa na farko yana da alaƙa da canje-canje a cikin yanayin hasken rana da aka daidaita, wanda zai haifar da manyan canje-canje a matakin tafkin a wannan tazara (25).Koyaya, lokacin da eccentricity na orbital ya faɗi bayan 85 ka kuma yanayin ya tsaya tsayin daka, ƙimar tallafin har yanzu yana da girma (0.68 m/ka).Wannan ya yi daidai da rikodin OSL na ƙasa, wanda ya nuna shaida mai yawa na fadada fan alluvial bayan kimanin 92 ka, kuma ya kasance daidai da bayanan mai sauƙi wanda ke nuna kyakkyawar dangantaka tsakanin yashwa da wuta bayan 85 ka (Ƙarin rubutu da Table S7).Bisa la'akari da kewayon kuskure na ikon sarrafa geochronological da ke akwai, ba shi yiwuwa a yi hukunci ko wannan saitin dangantaka ya samo asali ne a hankali daga ci gaban tsarin maimaitawa ko kuma ya fashe da sauri lokacin da aka kai matsayi mai mahimmanci.Bisa ga tsarin geophysical na juyin halitta na basin, tun daga tsakiyar Pleistocene (20), tsawaita tsagaitawa da abubuwan da ke da alaƙa sun ragu, don haka ba shine babban dalilin babban tsarin samar da fan da muka ƙaddara bayan 92 ka ba.
Tun daga tsakiyar Pleistocene, yanayi shine babban abin da ke sarrafa matakin ruwan tafkin (26).Musamman, ɗorawa na kwandon arewa ya rufe hanyar fita.800 ka don zurfafa tafkin har sai ya kai tsayin kofa na fitowar zamani (21).Ya kasance a ƙarshen ƙarshen tafkin, wannan mashigar ya ba da iyaka mafi girma ga matakin ruwan tafkin a lokacin tsaka-tsaki (ciki har da yau), amma ya ba da damar rufe kwandon ruwa yayin da ruwan tafkin ya fadi a lokacin bushewa (27).Sake gina matakin tafkin yana nuna sauye-sauyen busassun busassun busassun da rigar hawan keke a cikin 636 ka da suka gabata.Bisa ga shaida daga fossil pollen, matsanancin lokacin fari (> 95% raguwa a cikin ruwa duka) da ke hade da ƙananan hasken rana ya haifar da fadada ciyayi na hamada, tare da bishiyar da aka iyakance zuwa magudanar ruwa (27).Wadannan (tafkin) lows suna da alaƙa da pollen bakan, suna nuna babban rabo na ciyawa (80% ko fiye) da xerophytes (Amaranthaceae) a cikin kuɗin harajin bishiyar da ƙananan wadatar jinsuna (25).Sabanin haka, idan tafkin ya tunkari matakan zamani, ciyayi masu alaka da dazuzzukan tsaunuka na Afirka yakan wuce zuwa gabar tafkin [kimanin mita 500 sama da matakin teku (masl)].A yau, dazuzzukan tsaunuka na Afirka suna bayyana ne kawai a cikin ƙananan faci sama da 1500 masl (25, 28).
Matsakaicin lokacin fari na baya-bayan nan ya faru daga 104 zuwa 86 ka.Bayan haka, ko da yake matakin tafkin ya koma babban yanayi, buɗe wuraren daji na miombo tare da adadi mai yawa na ganye da kayan lambu sun zama gama gari (27, 28).Mafi mahimmancin harajin gandun daji na Afirka shine Podocarpus pine, wanda bai taɓa murmurewa zuwa darajar kwatankwacin matakin babban tafkin da ya gabata bayan 85 ka (10.7 ± 7.6% bayan 85 ka, yayin da irin wannan matakin tafkin kafin 85 ka shine 29.8 ± 11.8% ).Ma'anar Margalef (Dmg) kuma ya nuna cewa wadatar nau'in 85 da suka gabata shine 43% ƙasa da matakin babban tafkin da ya gabata (2.3 ± 0.20 da 4.6 ± 1.21, bi da bi), alal misali, tsakanin 420 da 345 ka (Ƙari). rubutu da adadi S5 da S6) (25).Samfurin pollen daga kusan lokaci.88 zuwa 78 ka kuma ya ƙunshi babban adadin pollen Compositae, wanda zai iya nuna cewa ciyayi sun damu kuma suna cikin kewayon kuskure na mafi tsufa kwanan wata lokacin da mutane suka mamaye yankin.
Muna amfani da hanyar rashin daidaituwar yanayi (29) don yin nazarin bayanan burbushin halittu da na paleoclimate na cores da aka haƙa kafin da kuma bayan 85 ka, da kuma nazarin dangantakar muhalli tsakanin ciyayi, yawan nau'in nau'in, da hazo da hasashen tsinkayar hasashen yanayi mai tsabta.Tuba yanayin asali na ~550 ka.Wannan yanayin da aka canza ya shafi yanayin hazo mai cike da tabkuna da gobara, wanda ke bayyana a cikin rashin nau'o'in nau'i da sabbin ciyayi.Bayan lokacin bushewa na ƙarshe, wasu abubuwan dazuzzuka ne kawai aka gano, gami da abubuwan da ke jure wuta na dazuzzukan tsaunin Afirka, kamar man zaitun, da abubuwan da ke jure wuta na dazuzzukan yanayi na yanayi, kamar Celtis (Ƙarin rubutu da Hoto S5) ( 25).Don gwada wannan hasashe, mun ƙirƙira matakan ruwan tafkin da aka samo daga ostracode da ma'adinan ma'adinai na gaskiya a matsayin masu canji masu zaman kansu (21) da kuma masu dogaro kamar gawayi da pollen wanda ƙarar wutar ta iya shafa (25).
Don bincika kamance ko bambance-bambance tsakanin waɗannan haɗuwa a lokuta daban-daban, mun yi amfani da pollen daga Podocarpus (bishiyar bishiyar har abada), ciyawa (ciyawa), da zaitun (bangaren dazuzzukan tsaunin Afirka) don babban bincike na daidaitawa (PCoA), da miombo (babban bangaren gandun daji a yau).Ta hanyar tsara PCoA a kan tsaka-tsakin tsaka-tsakin da ke wakiltar matakin tafkin lokacin da aka kafa kowane haɗin gwiwa, mun bincika yadda haɗin pollen ya canza game da hazo da kuma yadda wannan dangantaka ta canza bayan 85 ka (Hoto 3 da Hoto S7).Kafin 85 ka, samfuran tushen gramineous sun haɗu zuwa yanayin bushewa, yayin da samfuran tushen podocarpus suka haɗu zuwa yanayin rigar.Sabanin haka, samfuran bayan 85 ka an taru tare da mafi yawan samfurori kafin 85 ka kuma suna da ma'auni daban-daban, yana nuna cewa abun da ke ciki ba sabon abu bane don yanayin hazo iri ɗaya.Matsayin su a cikin PCoA yana nuna tasirin Olea da miombo, dukansu suna da fifiko a ƙarƙashin yanayin da suka fi dacewa da wuta.A cikin samfurori bayan 85 ka, Podocarpus pine kawai ya kasance mai yawa a cikin samfurori guda uku a jere, wanda ya faru bayan tazara tsakanin 78 da 79 ka fara.Hakan na nuni da cewa bayan da aka samu karuwar ruwan sama na farko, dajin ya yi kamar ya farfado a takaice kafin daga bisani ya ruguje.
Kowane batu yana wakiltar samfurin pollen guda ɗaya a wani wuri da aka bayar a lokaci, ta amfani da ƙarin rubutu da samfurin shekaru a cikin Hoto 1. S8.Vector yana wakiltar alkibla da saurin canji, kuma tsayin daka yana wakiltar yanayi mai ƙarfi.Ƙarƙashin ƙasa yana wakiltar matakin ruwa na tafkin a matsayin wakilin hazo;duhu blue ya fi girma.Matsakaicin ƙimar ƙimar fasalin PCoA an bayar da ita don bayanan bayan 85 ka (jajayen lu'u-lu'u) da duk bayanan daga matakan tabki masu kama kafin 85 ka (lu'u lu'u-lu'u).Yin amfani da bayanan duka 636 ka, "matakin tafkin da aka kwaikwayi" yana tsakanin -0.130-σ da -0.198-σ kusa da matsakaicin ƙimar ƙimar tafkin PCA.
Don yin nazarin dangantakar dake tsakanin pollen, matakin ruwa na tafkin da gawayi, mun yi amfani da bincike na multivariate na bambance-bambancen (NP-MANOVA) don kwatanta "muhalli" gaba ɗaya (wanda ke wakiltar matrix na pollen, matakin ruwa na tafkin da gawayi) kafin. da kuma bayan 85 ka canji.Mun gano cewa bambance-bambancen da haɗin kai da aka samu a cikin wannan matrix bayanai suna da bambance-bambance masu mahimmanci kafin da kuma bayan 85 ka (Table 1).
Bayanan mahalli na mu na ƙasa daga phytoliths da ƙasa a gefen Tekun Yamma sun yi daidai da fassarar da ta dogara da wakilin tafkin.Hakan na nuni da cewa duk da yawan ruwan tafkin, an rikide da yanayin zuwa wani wuri mai cike da budadden dajin dajin da ke da ciyawa, kamar yau (25).Duk wuraren da aka bincika don phytoliths a gefen yamma na basin suna bayan ~ 45 ka kuma suna nuna adadi mai yawa na murfin arboreal yana nuna yanayin rigar.Duk da haka, sun yi imanin cewa yawancin ciyawa yana cikin nau'i na buɗaɗɗen gandun daji wanda ya cika da bamboo da ciyawa mai firgita.Dangane da bayanan phytolith, itatuwan dabino marasa juriya (Arecaceae) suna wanzuwa ne kawai a bakin tafkin, kuma ba safai ba ne ko babu a wuraren binciken kayan tarihi na cikin gida (Table S8) (30).
Gabaɗaya magana, jika amma buɗaɗɗen yanayi a cikin marigayi Pleistocene kuma ana iya gano shi daga paleosols na ƙasa (19).Lagoon yumbu da ƙasa mai daskarewa carbonate daga wurin archaeological na ƙauyen Mwanganda za a iya gano su zuwa 40 zuwa 28 cal ka BP (wanda aka kwatanta da Qian'anni a baya) (Table S4).Yadudduka na ƙasa na carbonate a cikin gadon Chitimwe yawanci nodular calcareous (Bkm) da argillaceous da carbonate (Btk) yadudduka, wanda ke nuna wurin kwanciyar hankali na geomorphological da jinkirin daidaitawa daga fanin alluvial mai nisa Kimanin 29 cal ka BP (Ƙari). rubutu).Rushewar ƙasa mai taurin kai (dutsen lithic) da aka samu akan ragowar magoya baya na zamanin da yana nuna buɗaɗɗen yanayin shimfidar wuri (31) da hazo mai ƙarfi na yanayi (32), yana nuna ci gaba da tasirin waɗannan yanayi akan shimfidar wuri.
Taimakawa ga rawar da wuta ke takawa a cikin wannan canjin ya fito ne daga bayanan garwashin macro da aka haɗe na rijiyoyin burtsatse, da kwararar gawayi daga Central Basin (MAL05-1B/1C) gabaɗaya ya ƙaru daga kusan.175 katunan.Yawancin kololuwa suna biyo baya tsakanin kusan.Bayan 135 da 175 ka da 85 da 100 ka, matakin tafkin ya farfado, amma gandun dajin da jinsunan ba su farfaɗo ba (Ƙarin rubutu, Hoto na 2 da Hoto S5).Dangantakar da ke tsakanin kwararar gawayi da lalurar maganadisu na ruwan lake na iya nuna alamun tarihin gobara na dogon lokaci (33).Yi amfani da bayanai daga Lyons et al.(34) Tafkin Malawi ya ci gaba da lalata yanayin da aka kone bayan 85 ka, wanda ke nuna kyakkyawar dangantaka (Spearman's Rs = 0.2542 da P = 0.0002; Table S7), yayin da tsofaffin ƙwayoyin cuta suna nuna bambancin dangantaka (Rs = -0.2509 da P < 0.0001).A cikin kwandon arewa, guntuwar MAL05-2A tana da mafi zurfin wurin anka, kuma ƙaramin Toba tuff shine ~ 74 zuwa 75 ka (35).Ko da yake ba shi da hangen nesa na dogon lokaci, yana karɓar shigarwa kai tsaye daga cikin kwandon da aka samo bayanan archaeological.Bayanan gawayi na kwandon arewa sun nuna cewa tun daga alamar Toba crypto-tephra, shigar da gawayi mai tsanani ya karu a hankali a lokacin da shaidar archaeological ya fi kowa (Hoto 2B).
Shaidar gobarar da mutum ya yi na iya yin nuni da yadda aka yi amfani da shi da gangan akan sikelin wuri, yawan jama'a da ke haifar da kone-kone ko babba a wurin, canjin wadatar mai ta hanyar girbi dazuzzukan dazuzzuka, ko hadewar wadannan ayyukan.Mafarauta na zamani suna amfani da wuta don canza lada mai yawa (2).Ayyukansu suna ƙara yawan ganima, suna kiyaye shimfidar mosaic, kuma suna haɓaka bambance-bambancen yanayin zafi da nau'ikan matakan maye gurbin (13).Wuta kuma tana da mahimmanci ga ayyukan kan layi kamar dumama, dafa abinci, tsaro, da zamantakewa (14).Ko da ƙananan bambance-bambance a cikin tura wuta a waje da tashe-tashen hankula na yanayi na iya canza tsarin dazuzzuka, samun man fetur, da lokacin harbe-harbe.Rage murfin bishiyar da bishiyoyin da ke ƙasa yana iya haifar da zaizayar ƙasa, kuma asarar nau'in nau'in nau'in nau'in nau'in nau'in nau'in nau'in nau'in nau'in nau'in nau'in nau'in nau'in nau'in nau'in nau'in nau'in nau'in nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i nau'i-nau'i-nau'i).
A cikin bayanan archaeological kafin a fara MSA, ikon ɗan adam na sarrafa wuta ya kasance da kyau (15), amma ya zuwa yanzu, an yi amfani da shi azaman kayan aikin sarrafa shimfidar wuri ne kawai a cikin ƴan yanayin Paleolithic.Waɗannan sun haɗa da game da Australia.40 ka (36), Highland New Guinea.45 ka (37) yarjejeniyar zaman lafiya.50 ka Niah Cave (38) in Borneo lowland.A cikin Amurka, lokacin da ɗan adam ya fara shiga waɗannan halittu, musamman a cikin 20 na baya (16), ana ɗaukar wutan wucin gadi a matsayin babban abin da ke sake fasalin al'ummomin tsirrai da dabbobi.Dole ne waɗannan shawarwarin su kasance bisa ga shaidar da ta dace, amma a cikin yanayin daidaitawar kai tsaye na archaeological, geological, geomorphological, da paleoenvironmental data, an ƙarfafa hujjar dalili.Ko da yake ainihin bayanan ruwa na ruwa na bakin teku na Afirka a baya sun ba da shaida na canje-canjen wuta a baya game da 400 ka (9), a nan muna ba da shaida na tasirin ɗan adam daga abubuwan da suka dace na archaeological, paleoenvironmental, da geomorphological.
Gano gobarar da mutum ya yi a cikin bayanan yanayi na paleoenvironmental yana buƙatar shaidar ayyukan wuta da canje-canje na ɗan lokaci ko na wurare dabam dabam na ciyayi, yana tabbatar da cewa waɗannan canje-canjen ba a annabta su ta sigogin yanayi kaɗai ba, da kuma haɗuwa na ɗan lokaci / sarari tsakanin canje-canje a yanayin wuta da canje-canje a cikin ɗan adam. (29) Anan, shaida ta farko na yaɗuwar MSA da samar da fanfo a cikin tafkin Malawi ya faru ne a kusan farkon babban sake fasalin ciyayi na yanki.85 kati.Yawancin gawayi a cikin MAL05-1B/1C core yana nuna yanayin samar da gawayi da sakawa a yanki, a kusan 150 ka idan aka kwatanta da sauran rikodin 636 ka (Hoto S5, S9, da S10).Wannan sauyi yana nuna muhimmiyar gudummawar da wuta ke bayarwa don tsara abubuwan da ke tattare da yanayin halittu, wanda yanayi kadai ba zai iya bayyana shi ba.A cikin yanayin wuta na yanayi, walƙiya yakan faru a ƙarshen lokacin rani (39).Duk da haka, idan man ya bushe sosai, ana iya kunna wutar da mutum ya yi a kowane lokaci.A girman wurin, mutane na iya ci gaba da canza wutar ta hanyar tattara itacen daga ƙarƙashin dajin.Sakamakon ƙarshe na kowane nau'in wuta na mutum shine cewa tana da yuwuwar haifar da ƙarin cin ciyayi na itace, yana dawwama cikin shekara, kuma akan kowane ma'auni.
A Afirka ta Kudu, a farkon 164 ka (12), an yi amfani da wuta don maganin zafi na yin duwatsu.Tun daga 170 ka (40), an yi amfani da wuta a matsayin kayan aiki don dafa tubers na starchy, yin cikakken amfani da wuta a zamanin da.Abubuwan Wadatar Albarkatu-Yanayin Halittu (41).Gobarar shimfidar wuri tana rage murfin arboreal kuma kayan aiki ne mai mahimmanci don kiyaye filayen ciyawa da wuraren facin dazuzzuka, waɗanda sune ma'anar abubuwan da ke tattare da yanayin yanayin ɗan adam (13).Idan manufar canza ciyayi ko dabi'ar ganima ita ce ƙara konewar mutum, to wannan ɗabi'a tana wakiltar haɓakar sarƙar sarrafa wuta da tura wuta ta mutanen zamanin farko idan aka kwatanta da mutanen farko, kuma yana nuna dangantakarmu da wuta ta fuskanci canzawa tsakanin juna (7).Bincikenmu yana ba da ƙarin hanyar fahimtar canje-canjen amfani da wuta ta mutane a cikin Late Pleistocene, da tasirin waɗannan canje-canje akan yanayin su da yanayin su.
Fadada magoya bayan Late Quaternary alluvial a yankin na Karonga na iya kasancewa saboda canje-canje a yanayin konewa na yanayi a ƙarƙashin yanayin sama da matsakaicin ruwan sama, wanda ke haifar da haɓakar tsaunin tudu.Hanyar wannan abin da ya faru na iya zama martanin magudanar ruwa da tashin hankali ya haifar da tashin hankali da gobarar ke haifarwa, da haɓakawa da ci gaba da zazzagewa na sama na magudanar ruwa, da kuma faɗaɗa magoya bayan alluvial a cikin yanayin piedmont kusa da tafkin Malawi.Waɗannan halayen na iya haɗawa da canza kaddarorin ƙasa don rage ƙyalli, rage ƙarancin ƙasa, da haɓaka kwararar ruwa saboda haɗuwa da yanayin hazo mai girma da rage murfin arboreal (42).An fara inganta samar da siminti ta hanyar cire kayan da ke rufewa, kuma bayan lokaci, ƙarfin ƙasa na iya raguwa saboda dumama da rage ƙarfin tushen.Fitar da ƙasan saman yana ƙara jujjuyawar ruwa, wanda tarin sifar fanka ke ɗauka a ƙasa kuma yana haɓaka samuwar ƙasa ja akan sifar fan.
Abubuwa da yawa na iya sarrafa martanin da ke ƙasa game da sauya yanayin wuta, yawancinsu suna aiki cikin ɗan gajeren lokaci (42-44).Siginar da muke haɗawa anan a bayyane take akan sikelin lokacin millennium.Nazari da ƙirar juyin halitta sun nuna cewa tare da ɓarkewar ciyayi da aka samu sakamakon gobarar daji da aka maimaita, adadin la'antar ya canza sosai akan sikelin lokacin ƙarni (45, 46).Rashin bayanan burbushin yanki wanda ya zo daidai da canje-canjen da aka gani a bayanan gawayi da ciyayi yana hana sake gina tasirin halayen ɗan adam da sauye-sauyen muhalli akan abubuwan da ke tattare da al'ummomin herbivore.Duk da haka, manyan ciyayi da ke zaune a buɗe wuraren buɗe ido suna taka rawa wajen kiyaye su da hana mamaye ciyayi na itace (47).Shaidar canje-canje a sassa daban-daban na mahalli bai kamata a yi tsammanin faruwa lokaci guda ba, amma yakamata a gan shi azaman jerin abubuwan tarawa waɗanda zasu iya faruwa na dogon lokaci (11).Yin amfani da hanyar rashin daidaituwar yanayi (29), muna ɗaukar ayyukan ɗan adam a matsayin babban abin tuƙi wajen tsara yanayin arewacin Malawi a lokacin Late Pleistocene.Duk da haka, waɗannan tasirin na iya dogara ne akan abubuwan da suka faru a baya, wanda ba a bayyane yake ba na hulɗar mahalli da ɗan adam.Kololuwar gawayi wanda ya bayyana a cikin bayanan muhalli kafin farkon kwanan watan binciken kayan tarihi na iya haɗawa da wani ɓangaren ɗan adam wanda baya haifar da canje-canjen tsarin muhalli iri ɗaya kamar yadda aka rubuta daga baya, kuma baya haɗa da ajiya waɗanda suka isa don nuna gaba gaɗi na aikin ɗan adam.
Gajerun laka, irin su na Makwabciyar Tekun Masoko a Tanzaniya, ko kuma guntun laka a tafkin Malawi, sun nuna cewa yawan ciyayi da ciyayi na ciyayi ya canza, wanda ake dangantawa da shekaru 45 da suka gabata.Canjin yanayin yanayi na ka (48-50).Duk da haka, kawai kallo na dogon lokaci na rikodin pollen na tafkin Malawi> 600 ka, tare da yanayin tarihin archaeological da ke kusa da shi, yana yiwuwa a fahimci yanayi, ciyayi, gawayi, da ayyukan mutane.Ko da yake ana iya yiwuwa mutane su bayyana a arewacin tafkin Malawi kafin 85 ka, kimanin 85 ka, musamman bayan 70 ka, sun nuna cewa yankin yana da kyau ga mazaunin mutane bayan da babban lokaci na fari ya ƙare.A wannan lokacin, sabon ko mafi yawan amfani da wuta da mutane ke yi a fili yana haɗuwa tare da sauyin yanayi don sake gina dangantakar muhalli> 550-ka, kuma a ƙarshe ya kafa wuri na wucin gadi na farko kafin noma (Hoto 4).Ba kamar lokutan da suka gabata ba, yanayin yanayin shimfidar wuri yana kiyaye rukunin MSA, wanda shine aikin sake dawowa tsakanin mahalli (rarrabuwar albarkatu), halayen ɗan adam (tsararrun ayyuka), da kunna fan (ajiye/binne rukunin yanar gizo).
(A) Ku.400 ka: Ba za a iya gano ɗan adam ba.Yanayin danshi ya yi kama da na yau, kuma matakin tafkin yana da girma.Daban-daban, murfin arboreal mara jure wuta.(B) Kimanin 100 ka: Babu wani rikodin archaeological, amma ana iya gano kasancewar mutane ta hanyar kwararar gawayi.Yanayin bushewa yana faruwa a busassun magudanan ruwa.Gabaɗaya gadon gadon yana fallasa kuma ruwan saman yana da iyaka.(C) Kimanin 85 zuwa 60 ka: Ruwan tafkin yana ƙaruwa tare da haɓakar hazo.Ana iya gano wanzuwar ɗan adam ta hanyar ilimin kimiya na kayan tarihi bayan 92 ka, kuma bayan 70 ka, za a biyo bayan kona tuddai da faɗaɗa fanko.Wani ɗan bambanci, tsarin ciyayi mai jurewa wuta ya fito.(D) Kimanin 40 zuwa 20 ka: Shigar da gawayi na muhalli a cikin kwandon arewa ya karu.Samuwar magoya bayan alluvial ya ci gaba, amma ya fara raunana a ƙarshen wannan lokacin.Idan aka kwatanta da rikodin baya na 636 ka, matakin tafkin ya kasance mai girma da kwanciyar hankali.
Anthropocene yana wakiltar tarin ɗabi'un ginin gine-gine da aka haɓaka sama da dubban shekaru, kuma ma'aunin sa ya keɓanta ga Homo sapiens na zamani (1, 51).A cikin mahallin zamani, tare da gabatarwar noma, shimfidar wurare na mutum ya ci gaba da wanzuwa kuma yana ƙaruwa, amma su ne kari na tsarin da aka kafa a lokacin Pleistocene, maimakon raguwa (52).Bayanai daga arewacin Malawi sun nuna cewa lokacin canjin yanayi na iya tsawaita, rikitarwa da maimaituwa.Wannan sikelin canji yana nuna rikitaccen ilimin ilimin halittu na farkon mutanen zamani kuma yana kwatanta canjinsu zuwa manyan nau'ikan mu na duniya a yau.
Bisa ga ka'idar da Thompson et al., Binciken kan yanar gizo da kuma rikodin kayan tarihi da halayen dutse a kan yankin binciken.(53).Sanya rami na gwaji da tono babban wurin, gami da micromorphology da samfurin phytolith, sun bi ka'idar da Thompson et al ya bayyana.(18) da Wright et al.(19).Taswirar tsarin bayanan mu (GIS) bisa taswirar binciken yanayin ƙasa na Malawi na yankin yana nuna kyakkyawar alaƙa tsakanin Chitimwe Beds da wuraren binciken kayan tarihi (Hoto S1).Tazara tsakanin ramukan gwajin ƙasa da kayan tarihi a yankin Karonga shine ɗaukar mafi girman samfurin wakilci (Hoto S2).Ilimin geomorphology na Karonga, shekarun geological da binciken binciken kayan tarihi sun ƙunshi manyan hanyoyin binciken fage guda huɗu: binciken masu tafiya a ƙasa, ramukan gwajin kayan tarihi, ramukan gwajin ƙasa da cikakkun abubuwan tono wuraren.Tare, waɗannan fasahohin suna ba da damar yin samfuri na babban fallasa gadon Chitimwe a arewa, tsakiya, da kudancin Karonga (Hoto S3).
Binciken da aka yi a wurin da rikodin kayan tarihi da sifofin dutse a kan yankin binciken masu tafiya a ƙasa sun bi ƙa'idar da Thompson et al ya bayyana.(53).Wannan hanya tana da manyan manufofi guda biyu.Na farko shi ne a gano wuraren da kayayyakin al’adu suka lalace, sannan a sanya ramukan gwaje-gwajen archaeological a wadannan wurare domin dawo da kayayyakin al’adu da ke wurin daga muhallin da aka binne.Buri na biyu shi ne yin rikodin rarraba kayan tarihi a hukumance, da halayensu, da dangantakarsu da tushen kayan dutse na kusa (53).A cikin wannan aikin, ƙungiyar mutane uku ta yi tafiya a nisan mita 2 zuwa 3 don jimlar kilomita 147.5 na layi, ta ratsa yawancin gadajen Chitimwe da aka zana (Table S6).
Aikin da farko ya mayar da hankali kan gadaje na Chitimwe don haɓaka samfuran kayan tarihi da aka lura, na biyu kuma ya mayar da hankali kan dogayen sassan layi ɗaya daga gabar tafkin zuwa tsaunukan tsaunuka waɗanda ke ratsa sassa daban-daban na sedimentary.Wannan yana tabbatar da babban abin lura cewa kayan tarihi da ke tsakanin tsaunukan yamma da bakin teku suna da alaƙa kawai da gadon Chitimwe ko kuma na baya-bayan nan na Late Pleistocene da ruwan holocene.Kayan kayan tarihi da aka samu a wasu wuraren ajiya ba a waje ne, ana ƙaura daga wasu wurare a cikin fili, kamar yadda ake iya gani daga yawansu, girmansu, da yanayin yanayi.
Ramin gwajin archaeological a wurin da tona babban wurin, gami da micromorphology da samfurin phytolith, sun bi ka'idar da Thompson et al ya bayyana.(18, 54) da Wright et al.(19, 55).Babban maƙasudin shine fahimtar rarrabawar ƙasa na kayan tarihi da simintin fanti a cikin mafi girman wuri.Yawanci ana binne kayan tarihi da zurfi a duk wuraren da ke Chitimwe Beds, sai dai gefuna, inda yazayar ƙasa ta fara cire saman ruwan.A yayin binciken na yau da kullun, mutane biyu sun wuce Chitimwe Beds, waɗanda aka nuna a matsayin taswira a taswirar yanayin ƙasa na gwamnatin Malawi.A lokacin da wadannan mutane suka ci karo da kafadun damshin Bed na Chitimwe, sai suka fara tafiya a gefen gefen, inda suke ganin kayan tarihi da suka gushe daga ruwan.Ta hanyar karkatar da abubuwan da aka tono dan kadan zuwa sama (3 zuwa 8 m) daga kayan tarihi masu rugujewa, tonowar na iya bayyana matsayinsu a cikin wurin dangane da lakar da ke dauke da su, ba tare da bukatar hakowa mai yawa a gefe ba.Ana sanya ramukan gwajin ta yadda za su yi nisan mita 200 zuwa 300 daga ramin mafi kusa, ta yadda za a iya samun sauye-sauye a cikin ruwan gadon Chitimwe da kayan tarihi da ke cikinsa.A wasu lokuta, ramin gwajin ya bayyana wani wuri wanda daga baya ya zama cikakken wurin tono.
Duk ramukan gwaji suna farawa da murabba'in 1 × 2 m, suna fuskantar arewa-kudu, kuma ana hako su cikin raka'a na 20 cm na sabani, sai dai in launi, rubutu, ko abun ciki na laka ya canza sosai.Yi rikodin abubuwan sedimentology da kaddarorin ƙasa na duk abubuwan da aka tono, waɗanda ke wucewa daidai gwargwado ta busasshen sieve na mm 5.Idan zurfin zurfafawa ya ci gaba da wuce 0.8 zuwa 1 m, dakatar da tono a cikin ɗaya daga cikin murabba'in murabba'in biyu kuma ci gaba da tono a ɗayan, ta haka ne za ku samar da "mataki" don ku iya shiga cikin zurfin yadudduka lafiya.Daga nan kuma a ci gaba da tono har sai an kai ga tudun, aƙalla 40 cm na ɗigon gurɓatattun kayan tarihi suna ƙasa da tarin kayan tarihi, ko kuma tonon ya zama marar aminci (zurfi) don ci gaba.A wasu lokuta, zurfin zurfafawa yana buƙatar tsawaita ramin gwajin zuwa murabba'in murabba'in na uku kuma shigar da maɓalli a cikin matakai biyu.
Ramin gwajin yanayin kasa sun nuna a baya cewa Chitimwe Beds yakan bayyana akan taswirar kasa saboda bambancin launin ja.Lokacin da suka haɗa da magudanar ruwa da ruwan kogi, da kuma ruwan fanfo, ba koyaushe suke bayyana ja (19).Geology Ramin gwajin an tono shi a matsayin rami mai sauƙi wanda aka tsara don cire gauraye na sama da aka gauraya don bayyanar da ɓoyayyen ɓoyayyiyar ƙasa.Wannan ya zama dole saboda gadon Chitimwe ya ruguje zuwa wani tudu mai kama-da-wane, kuma akwai tarkace da suka ruguje a kan gangaren, wanda yawanci ba sa bayyana sassa na halitta ko yanke.Don haka, ko dai an yi wannan tonon sililin ne a saman gadon Chitimwe, mai yiwuwa an yi cudanya da juna a karkashin kasa tsakanin gadon Chitimwe da Pliocene Chiwondo gadon da ke kasa, ko kuma sun faru ne a inda ake buqatar a yi kwanan wata terrace na kogin (55).
Ana gudanar da cikakken tonon kayan tarihi na archaeological a wuraren da ke yin alkawalin ɗimbin tarin kayan aikin dutse a cikin wurin, yawanci bisa ramukan gwaji ko wuraren da za a iya ganin adadi mai yawa na kayan al'adu suna zubewa daga gangaren.An gano manyan abubuwan al'adun gargajiya da aka tono daga raka'a na sedimentary da aka tono daban a cikin murabba'in 1 × 1 m.Idan girman kayan kayan tarihi ya yi girma, sashin tono shine 10 ko 5 cm spout.An zana dukkan kayayyakin dutse, kasusuwan kasusuwa da ocher yayin kowane babban hako, kuma babu iyaka girman.Girman allo shine 5mm.Idan an gano abubuwan al'adu yayin aikin tono, za'a sanya musu lambar gano lambar zane ta musamman, kuma za'a sanya lambobin binciken da ke cikin jeri guda zuwa ga abubuwan da aka tace.An yi wa kayan tarihin al'adu alamar tawada na dindindin, an sanya su cikin jakunkuna masu alamun samfuri, da kuma jakunkuna tare da sauran kayan tarihi na al'adu daga tushe iri ɗaya.Bayan bincike, ana adana duk kayan tarihi na al'adu a Cibiyar Al'adu da Gidan Tarihi ta Karonga.
Ana aiwatar da duk abubuwan tonowa bisa ga ma'aunin yanayi.An raba waɗannan zuwa tofi, kuma kauri na tofi ya dogara da yawa na kayan aiki (misali, idan ƙarancin kayan aikin ya yi ƙasa, kaurin tofin zai yi girma).Bayanan bayan fage (misali, kaddarorin najasa, alaƙar baya, da lura da tsangwama da yawan kayan tarihi) ana yin rikodin su a cikin bayanan Access.Duk bayanan daidaitawa (misali, binciken da aka zana a cikin ɓangarori, haɓaka mahallin, sasanninta murabba'i, da samfurori) sun dogara ne akan haɗin gwiwar Universal Transverse Mercator (UTM) (WGS 1984, Zone 36S).A babban rukunin yanar gizon, ana yin rikodin duk maki ta amfani da jerin Nikon Nivo C jimlar 5″ jimlar tasha, wacce aka gina akan grid na gida kamar yadda zai yiwu zuwa arewacin UTM.Wurin da ke kusurwar arewa maso yamma na kowane wurin hakowa da wurin kowane wurin tono An ba da adadin laka a cikin tebur S5.
An yi rikodin ɓangaren sedimentology da halayen kimiyyar ƙasa na duk raka'a da aka tono ta amfani da Shirin Sashe na Aikin Noma na Amurka (56).An ƙayyadadden raka'a na sedimentary bisa girman hatsi, angular, da halayen kwanciya.Yi la'akari da rashin daidaituwa da rikice-rikice masu alaƙa da sashin laka.Ana ƙayyade ci gaban ƙasa ta hanyar tarin sesquioxide ko carbonate a cikin ƙasan ƙasa.Ana yin rikodin yanayin ƙasa (misali, redox, samuwar nodules na manganese) akai-akai.
An ƙayyade wurin tattara samfuran samfuran OSL bisa ƙididdigewa wanda facies zai iya samar da ingantaccen ƙididdigewa na shekarun binne ɓarna.A wurin da aka yi samfurin, an haƙa ramuka don fallasa ainihin abin da ake yi na sedimentary.Tattara duk samfuran da aka yi amfani da su don saduwa da OSL ta hanyar saka bututun ƙarfe mara nauyi (kimanin 4 cm a diamita kuma kusan 25 cm a tsayi) a cikin bayanin martaba.
OSL Dating yana auna girman rukunin electrons da aka kama a cikin lu'ulu'u (kamar ma'adini ko feldspar) saboda fallasa ga radiation ionizing.Yawancin wannan radiation yana fitowa ne daga ruɓar isotopes na rediyoaktif a cikin muhalli, kuma ƙananan adadin ƙarin abubuwan da ke cikin latitudes na wurare masu zafi suna bayyana a cikin nau'i na radiation na sararin samaniya.Ana fitar da electrons ɗin da aka kama a lokacin da crystal ya fallasa zuwa haske, wanda ke faruwa a lokacin sufuri (fitilar sifili) ko a cikin dakin gwaje-gwaje, inda hasken ke faruwa akan firikwensin da zai iya gano photons (misali, bututu na hoto ko kyamara mai caji. na'ura mai haɗawa) Ƙarƙashin ɓangaren yana fitarwa lokacin da lantarki ya dawo cikin yanayin ƙasa.Ma'adini barbashi tare da girman tsakanin 150 da 250 μm an rabu da sieving, acid magani da kuma yawa rabuwa, da kuma amfani da a matsayin kananan aliquots (<100 barbashi) saka a saman wani aluminum farantin ko hakowa a cikin 300 x 300 mm da kyau. Ana nazarin barbashi akan kwanon aluminum.Yawan adadin da aka binne ana ƙididdige shi ta hanyar amfani da hanyar farfadowar aliquot guda ɗaya (57).Baya ga yin la'akari da adadin radiation da hatsi ya karɓa, OSL dating kuma yana buƙatar ƙididdige adadin kashi ta hanyar auna ma'auni na radionuclide a cikin sediment na samfurin da aka tattara ta amfani da binciken gamma spectroscopy ko neutron activation analysis, da kuma ƙayyade samfurin bincike na cosmic kashi Wuri da zurfin binnewa.Ana samun ƙayyadaddun shekaru na ƙarshe ta hanyar rarraba kashi na binne ta hanyar adadin kashi.Koyaya, lokacin da aka sami canji a cikin adadin da aka auna ta hatsi ɗaya ko rukuni na hatsi, ana buƙatar ƙirar ƙididdiga don ƙayyade adadin da aka binne da ya dace don amfani.Ana ƙididdige adadin da aka binne a nan ta hanyar amfani da tsarin tsakiyar zamani, a cikin yanayin saduwar aliquot guda ɗaya, ko kuma a yanayin saduwar barbashi ɗaya, ta amfani da ƙirar gauraya iyaka (58).
Dakunan gwaje-gwaje masu zaman kansu guda uku sun yi nazarin OSL don wannan binciken.Ana nuna cikakkun hanyoyin kowane ɗakin gwaje-gwaje a ƙasa.Gabaɗaya, muna amfani da hanyar sake haɓakawa don amfani da OSL Dating zuwa ƙananan aliquots (dubun hatsi) maimakon yin amfani da ƙididdigar ƙwayar hatsi ɗaya.Wannan shi ne saboda a lokacin gwajin haɓakar haɓakawa, ƙimar dawowar ƙaramin samfurin yana da ƙasa (<2%), kuma siginar OSL ba ta cika ba a matakin siginar yanayi.Matsakaicin daidaituwa tsakanin dakin gwaje-gwaje na kayyade shekaru, daidaiton sakamakon a ciki da tsakanin bayanan bayanan da aka gwada, da daidaito tare da fassarar geomorphological na shekarun 14C na dutsen carbonate sune tushen tushen wannan kima.Kowane dakin gwaje-gwaje ya kimanta ko aiwatar da yarjejeniyar hatsi guda ɗaya, amma da kansa ya ƙaddara cewa bai dace da amfani ba a cikin wannan binciken.Ana ba da cikakkun bayanai da ƙa'idodin bincike da kowane ɗakin gwaje-gwaje ke bi a cikin ƙarin kayan da hanyoyin.
Abubuwan da aka gano na dutse da aka gano daga tonowar da aka sarrafa (BRU-I; CHA-I, CHA-II, da CHA-III; MGD-I, MGD-II, da MGD-III; da SS-I) sun dogara ne akan tsarin awo da inganci. halaye.Auna nauyi da matsakaicin girman kowane kayan aiki (ta amfani da sikelin dijital don auna nauyin shine 0.1 g; ta amfani da caliper dijital na Mitutoyo don auna duk girman shine 0.01 mm).Hakanan ana rarraba duk kayan tarihi na al'adu bisa ga albarkatun ƙasa (ma'adini, quartzite, flint, da sauransu), girman hatsi (lafiya, matsakaici, m), daidaiton girman hatsi, launi, nau'in cortex da ɗaukar hoto, yanayin yanayi / zagaye gefen da ƙimar fasaha (cikakke ko gutsuttsura) Ƙaƙƙasa ko ɓangarorin, ɓangarorin ɓangarorin ƙwanƙwasa, duwatsun guduma, gurneti da sauransu).
Ana auna ma'auni tare da iyakar tsayinsa;iyakar nisa;nisa shine 15%, 50%, da 85% na tsayi;matsakaicin kauri;kauri shine 15%, 50%, da 85% na tsayi.An kuma yi ma'auni don kimanta girman kaddarorin ainihin ƙwayoyin hemispherical (radial da Levallois).Dukkanin madaidaicin maƙallan da aka karye ana rarraba su bisa ga hanyar sake saiti (dandali ɗaya ko dandamali da yawa, radial, Levallois, da sauransu), kuma ana ƙididdige tabo mai banƙyama a ≥15 mm da ≥20% na tsayin ainihin.Ƙwayoyin da ke da tabo na 5 ko ƙasa da 15 mm an rarraba su azaman "bazuwar".An yi rikodin ɗaukar hoto na gabaɗayan ainihin farfajiyar, kuma an yi rikodin ɗaukar hoto na dangi na kowane gefe akan ainihin ƙwayar hemispherical.
Ana auna takardar tare da iyakar tsayinsa;iyakar nisa;nisa shine 15%, 50%, da 85% na tsayi;matsakaicin kauri;kauri shine 15%, 50%, da 85% na tsayi.Yi bayanin gutsuttsura bisa ga sauran sassan (kusanci, tsakiya, nisa, tsaga dama kuma raba a hagu).Ana ƙididdige elongation ta hanyar rarraba matsakaicin tsayi da matsakaicin nisa.Auna faɗin dandali, kauri, da kusurwar dandalin waje na yanki mara kyau da guntun yanki na kusa, kuma a rarraba dandamali gwargwadon matakin shiri.Yi rikodin ɗaukar hoto da wuri akan duk yanki da guntu.An rarraba gefuna masu nisa bisa ga nau'in ƙarewa (tsunku, hinge, da cokali mai yatsa).A kan cikakken yanki, yi rikodin lamba da alkiblar tabo akan yanki na baya.Lokacin da aka ci karo da shi, yi rikodin wurin gyarawa da cin zarafi daidai da ƙa'idar da Clarkson ya kafa (59).An qaddamar da tsare-tsaren gyare-gyare don yawancin haɗe-haɗen hakowa don kimanta hanyoyin maidowa da amincin jigon wurin.
Abubuwan kayan aikin dutse da aka dawo dasu daga ramukan gwaji (CS-TP1-21, SS-TP1-16 da NGA-TP1-8) an kwatanta su bisa ga tsari mai sauƙi fiye da tono mai sarrafawa.Ga kowane kayan tarihi, an yi rikodin halaye masu zuwa: albarkatun ƙasa, girman barbashi, ɗaukar hoto, ƙimar girman, yanayin yanayi/lalacewar gefe, abubuwan fasaha, da adana gutsuttsura.Ana yin rikodin bayanin bayanin kula da sifofin bincike na flakes da muryoyin.
An yanke cikakkun tubalan na ruwa daga sassan da aka fallasa a cikin tono da ramukan ƙasa.An kafa wa]annan duwatsu a wurin da bandejin filasta ko takardar bayan gida da kuma tef ɗin marufi, sa'an nan kuma an kai su zuwa dakin gwaje-gwaje na Archaeology na Jami'ar Tubingen a Jamus.A can, ana bushe samfurin a 40 ° C na akalla sa'o'i 24.Sa'an nan kuma a warke su a karkashin vacuum, ta yin amfani da cakuda polyester resin da styrene da ba a inganta a cikin wani rabo na 7:3.Methyl ethyl ketone peroxide ana amfani dashi azaman mai kara kuzari, cakudawar guduro-styrene (3 zuwa 5 ml/l).Da zarar cakuda resin ya yi gelled, zafi samfurin a 40 ° C na akalla sa'o'i 24 don taurare cakuda gaba daya.Yi amfani da abin gani na tayal don yanke samfurin taurin cikin guda 6 × 9 cm, manna su akan faifan gilashi kuma niƙa su zuwa kauri na 30 μm.Sakamakon yankan an duba su ta hanyar amfani da na'urar daukar hoto mai kwance, kuma an yi nazari ta amfani da hasken polarized jirgin sama, hasken giciye, hasken abin da ya faru, da shuɗi mai haske tare da tsirara ido da haɓaka (×50 zuwa × 200).Kalmomi da bayanin sassan bakin ciki sun bi jagororin da Stoops (60) da Courty et al suka buga.(61).An yanke nodules na carbonate na ƙasa wanda aka tattara daga zurfin> 80 cm cikin rabi don a iya yin ciki da rabi kuma a yi shi a cikin yankan bakin ciki (4.5 × 2.6 cm) ta amfani da madaidaicin sitiriyo microscope da microscope petrographic da cathodoluminescence (CL) Binciken microscope. .Kula da nau'in carbonate yana da matukar taka tsantsan, saboda samuwar carbonate na ƙasa yana da alaƙa da kwanciyar hankali, yayin da samar da carbonate na ruwa na ƙasa ya kasance mai zaman kansa daga ƙasa ko ƙasa.
An yi amfani da samfurori daga saman da aka yanke na nodules na carbonate na ƙasa da aka raba kuma an raba su don nazari daban-daban.FS ta yi amfani da ma'aunin sitiriyo da na'urori masu ƙima na Geoarchaeology Working Group da CL microscope na Gwajin Ma'adinan Ma'adinai don nazarin ɓangarorin bakin ciki, dukansu suna cikin Tübingen, Jamus.An haƙa ƙananan samfurori na haɗin gwiwar radiocarbon ta hanyar yin amfani da madaidaicin horo daga wani yanki da aka keɓe na kimanin shekaru 100.Sauran rabin nodules shine 3 mm a diamita don guje wa wuraren da ke da recrystallization na marigayi, ma'adinan ma'adinai masu wadata, ko manyan canje-canje a cikin girman lu'ulu'u na calcite.Ba za a iya bin ƙa'idar guda ɗaya ba don samfuran MEM-5038, MEM-5035 da MEM-5055 A.Ana zaɓar waɗannan samfuran daga samfuran sinadarai marasa lahani kuma suna da ƙanƙanta da za a yanke su cikin rabin don sassan bakin ciki.Duk da haka, an gudanar da nazarin ƙananan sassa a kan samfurori na micromorphological daidaitattun abubuwan da ke kusa (ciki har da nodules na carbonate).
Mun ƙaddamar da samfurori na 14C na saduwa da Cibiyar Nazarin Isotope (CAIS) a Jami'ar Jojiya, Athens, Amurka.Samfurin carbonate yana amsawa tare da 100% phosphoric acid a cikin jirgin ruwa da aka kwashe don samar da CO2.Ƙarƙashin ƙarancin zafin jiki na samfuran CO2 daga wasu samfuran amsawa da jujjuyawar kuzari zuwa graphite.An auna rabon graphite 14C/13C ta amfani da ma'aunin totur na 0.5-MeV.Kwatanta rabon samfurin tare da rabon da aka auna tare da ma'aunin oxalic acid I (NBS SRM 4990).Ana amfani da marmara na Carrara (IAEA C1) azaman bango, kuma ana amfani da travertine (IAEA C2) azaman ma'auni na sakandare.An bayyana sakamakon a matsayin kashi na carbon na zamani, kuma an ba da kwanan wata da ba a tantance ba a cikin shekaru radiocarbon (shekarun BP) kafin 1950, ta amfani da rabin rayuwar 14C na shekaru 5568.An kawo kuskuren azaman 1-σ kuma yana nuna kuskuren ƙididdiga da gwaji.Dangane da ƙimar δ13C da aka auna ta hanyar isotope rabo mass spectrometry, C. Wissing of the Biogeology Laboratory in Tubingen, Jamus, ya ruwaito kwanan watan rabon isotope, ban da UGAMS-35944r da aka auna a CAIS.An yi nazarin samfurin 6887B a cikin kwafi.Don yin wannan, ƙaddamar da ƙaramin samfurin na biyu daga nodule (UGAMS-35944r) daga yankin samfurin da aka nuna akan yankan.An yi amfani da madaidaicin daidaitawa na INTCAL20 (Table S4) (62) da aka yi amfani da shi a yankin kudancin duniya don gyara ɓarkewar yanayi na duk samfuran zuwa 14C zuwa 2-σ.