
kreetteshyasile dhruva vanangal

creatasius dhruva vanangal mesosoic kaalaghattatthinte avasana kaalaghattatthil dhruva akshamshangalil valarnna mitasheetoshna vanangalaayirunnu, ithu creatasius kaalayalav 145-66 Ma ennariyappedunnu. eee kaalayalavil, aagola sharashari thaapanila ekadesham uyarnnathum kaarban dye ooksaidinte (sioo2) alavu ekadesham 1000 parts perr milyan (ppm) aayirunnu, ithu bhoomiyude anthareekshathile nilavile saandrathayude randara madangu varum. anthareeksha kaarban dye ooksaidinte samriddhi aagola kaalaavasthayilum bhoomiyude prakrithi samvidaanangalilum valare kaaryamaaya swaadheenam chelutthi, kaaranam athinte saandrata creatasius samayat oru harithagriha bhoomiyude vikasanathile pradhana gadakangalilonnaayi kanakkaakkappedunnu, aagola thaapanilayude sharashari valare kuravaanu. thalphalamaayi, rund ardhagolangalileyum uyarnna paaliyolettityoodukal innathethinekkaal valare choodaayirunnu. dhruvapradesangalil bhookhandangalude manjupaalikal illaathirikkunnathinu eee thaapanila gradient bhaagikamaayi kaaranamaayi.
uyarnna aagola thaapanilayodulla prathikaranamaayi, samudrathinte uparithalathil ninnulla eerppathinte baashpeekaranam kaaranam bhoomiyude jalachakram ganyamaayi vardhichu. eee kaalayalavil samudranirappu nilavile nirappinekkaal valare uyarnna nilayilaayirunnu. samudrajalathinte bhookhanda kaiyettam epyric samudrangalude vishalatha ulppede vyapakamaaya aazhamillaatha samudrangal roopappeduthi.
aazhamillathathum choodullathumaaya samudrajalathinum anthareekshathinum edayilulla uparithala vistheernnathile vardhanavu uyarnna baashpeekarana nirakkum vividha akshamshangalil kooduthal mazhayum anuvadikkukayum kooduthal mitasheetoshna aagola kaalavastha srishtikkukayum cheiyunnu. vyapakamaaya mitasheetoshna kaalavastha uyarnna akshamsha aavaasavyavasthayilum kaaryamaaya swaadheenam chelutthi.
cretatius dhruva vanangal.
cretatius dhruva seasonukalil uyarnna akshaamshangalile nilavile avasthakalil ninnu sradheyamaaya vyathyasam undayirunnathinaal cretatius samayat, samasheethoshna vanangal dhruva akshamshangalil abhivridhippettu. venalkkaala sooryaprakaashathinteyum shaityakaala iruttinteyum dairkhyam ekadesham 5 maasam veetham neenduninnu. prakaashatthile eee vyathiyaanam dhruva vanangalude ghadanayilum parinaamatthilum nirnaayaka punk vahichathayi karuthappedunnu. vadakkan, thekkan ardhagolangalil 85° akshaamsham vare paaliyophorastukalude saannidhyam phoosil cheytha sasyajaalangalude thelivukal soochippikkunnu. kazhinja 100 dasalaksham varshangalil eee uyarnna akshaamshangalile sasyajaalangalude prabalamaaya roopangal athivegam vikasikkukayum aathyanthikamayi cretatius terrestrial revolution ennariyappedunna oru samayat maattisthaapikkappedum cheythu. cretatius bhoumaviplavathinte samayat, coniferukal, saikkaadukal, fernukal ennivaykku pakaram angiospermukalum jimnospermukalum thiranjedutthu uyarnna paaliyolettityoodukal aadhipathyam pulartthunna pradhana inamaayi maari. eee cretatius harithagriha lokath, artic conifer vanangal pradhaanamaayum elapozhiyum vanangalayi kanakkaakkappettirunnu, athesamayam antaarttikkayil valarunnavayil nithyaharithangalude anupatham ganyamaayi kooduthalaanu.
126 dasalaksham varshangalkk munbu australiyayile aadyathe angiosper pookkunnathaayi 2019 leeii oru patanam velippeduthi, ithu thekkan australiyayile dhruva kasherukkalude theeyathi 126-110 dasalaksham varshangalkk munbu parishkarichu.
vanavaividhyam.
ekadesham 130 dasalaksham varshangalkk munbu, aadyakaala kreetteshyasil, aanjiyospermukalude oru valia vaividyavalkkaranam undaayirunnu, athu uyarnna paleolatitude vanaghadanayil oru valia parinamaparamaaya maattathinu thudakkamittu. aanjiyospermukalude vaividyavalkkaranam koombola, thaine shekharikkunna praanikalumayi adutha bandhamullathaan. eee praanikalude vaividyavalkkaranam angiosper speeshiyeshan nirakkil ganyamaaya swaadheenam cheluthumennu karuthappedunnu. vaividhyavalkkaranathinulla samvidaanam enthuthanneyaayaalum, aadyakaala cretatius angiosper "ettedukkal" aavaasavyavasthayude oru pradhana parivartthanatthe soochippikkunnu. kreeteshyasinte avasaanathode, dhruva vanapradeshangalude ghadana ekadesham 50-80% aayi vaividyavathakarikkappettu. coniferukal, saikkaadukal, fernukal ennivayil ninnu pradhaanamaayum aanjiyospermukalilekkula eee maattam praadeshika dhruva kaalavasthayumaayulla rasakaramaaya parinamaparamaaya poruthappedutthaline prathifalippikkunnu, koodaathe kadaltheerathinte vyaapana nirakk, yoostaatik samudranirappu, uyarnna aagola thaapanila thudangiya niravadhi gadakangalum prathifalippikkunnu.
paaristhithika uthppaadanakshamatha.
cretatius samayat mitasheetoshna mekhalayude dhruvathilekkulla sthaanachalanathil bhouma vanathinte praadhamika uthppaadanakshamatha ganyamaayi vardhichu. uyarnnathum madhyathilullathumaaya paaliyoletyoodukalil, kuranja paaliyoletyoodukalumaayi thaarathamyappeduthumbol vanaa uthppaadanakshamatha erattiyaayi kanakkaakkappedunnu. uyarnna paaliyoletyoodukalile bhouma uthppaadanakshamatha uyarnna anthareeksha kaarban dye ooksaidinte saandrathayumaayi shakthamayi bandhappettirikkunnu. vividha kaarban dye ooksaidinte saandrathaykku keezhil elapozhiyum nithyaharitha vrukshangalude valarchayekkurichulla pareekshanangalil ninnulla phalangal vyathyasthamaaya prathyaaghaathangal kaanikkunnu.
kaarban dye ooksaidinte saandrata, verukalude shwasana nirakk, thaapanila, prakaashasamsleshanam enningane naalu pradhana gadakangalaanu vanathinte motham uthppaadanakshamathaykku kaaranamaakunnath. kaarban dye ooksaid maathram prakaashasamshleshanathinte prakasha compensation pooyint kurachukondu ilayum verukalum shwasikkunnathu kuraykkunnu, ithu oru divasathil kaarban upabhogathil motham positteev nettam anuvadikkunnu. verukalude shwasanam kurayunnathu verukalude valarchaykku thudakkamidukayum aathyanthikamayi poshakangalum jalathinte upabhogakshamathayum mechappeduthukayum cheiyunnu. kaarban dye ooksaidinte phalangalil prakaashasamsleshanam cherkkumbol, praadeshika thapanilaye aashrayich vanaa uthppaadanakshamatha ganyamaayi vardhikkunnu. naalu shaareerika gadakangaludeyum samyojanam vanaa uthppaadanakshamathayil ganyamaaya vardhanavinu kaaranamaakunnu. pareekshanathmaka phalangal anusarichu, deerghakaalam jeevikkunna nithyaharitha elakalulla vruksha enangal kaarban dye ooksaid sambannamaaya anthareekshathil ettavum kooduthal prayojanam cheiyunnu, kaaranam avayude deerghakaala valarchaa kaalavum kreeteshyasinte mitasheetoshna dhruva paaliyolettityoodukal thazhachuvalaraan anuvadikkunna melaala vikasanam polulla poruthappedutthalukalum kaaranam.
phosilvalkkaricha vanam.
uyarnna akshaamshathilulla cretatius vanangalude ghadanayum ghadanayum praadhamikamaayi elapozhiyum coniferukal, fernukal, angiospermukal, jimnospermukal ennivayaal nirmmithamaayirunnu. ettavum samriddhavum aagolathalathil vyapakavumaaya sasya varggam arocarioid, podocarpoid coniferukal aayirunnu, avaa ekadesham 80 digri rund ardhagolangalilekkum vyaapichukidakkukayum melaappukalude 90 sathamaanathiladhikam nithyaharitha sasyangal srishtikkukayum cheiyunnu. mattu tharatthilulla coniferukal, samriddhamaayi kaanappedunnundengilum, rund ardhagolangalileyum madhya, thaazhnna akshamshangalil parimithappedutthiyirunnu, pradhaanamaayum praadeshika kaalavasthayaal parimithappedutthiyirunnu. aagola kaalavastha vikasichathode, aanjiyospermukalude uyarcha uyarnna akshaamshangalile konifarukalkku mail sammarddam cheluthukayum aathyanthikamayi sooryaprakaashathinaayulla pooraattatthil vijayikkukayum cheythu. 25 dasalaksham varshangalkk sesham vaividhyamaarnna angiosper speesheesukalude druthagathiyilulla parinamam oduvil madhya-cretatius vazhi prabalamaaya vruksha tharamaayi maari. cretatius kaalaghattatthinte avasaanathode, vadakkan, thekkan ardhagolathile mitasheetoshna kaalavastha vividha angiospermukaludeyum oru paridhivare konifarukaludeyum druthagathiyilulla vaividhyavalkkaranathinum vitharanathinum anuyojyamaayirunnu. madhya-cretatius paaliyorekkordinekkure padanangal, vadakkan ardhagolathile uyarnna paaliyolettityoodukale vanaghadanakalil pradhaanamaayum mishrita nithyaharitha, elapozhiyum vruksha tharangal adhivasikkunnundenn nigamanam cheiyunnu. ithinu vipareethamaayi, thekkan ardhagolathil pradhaanamaayum nithyaharithangal undaayirunnu.
glosopteris parvathatthinte thekkupadinjaaran tholil kaanapedunna phoosil maratthinte oru pradhana pradesamaanu museum ledge.
paaliyoklaimettu proxikal.
paaliyoklaimettu proxy ennum ariyappedunna oru paaliyoklaimettu indikkettarin munkaalangalil aagola kaalavastha enganeyaayirikkumennathuku pradhana vivarangal velippeduthaan kazhiyum. marangalude valarchaa valayangal, aazhakkadal korukal, aise korukal, paaliyosolukal ennivayekkurichulla paaliyoklaimettu padanangal paalioklaimettukalile pradhana nirbbandhangal vilayiruthaan upayogikkunna niravadhi saadhaarana proxikalil chilathaanu.
paleothermometry.
hydrajan, ooksijan thudangiya sthirathayulla isodoppukalile isotope-anupatham maas spectrometry daattayude vishakalanamaan paleothermometry punarnirmmaanathinulla ettavum pradhanappettathum moolyavathaayathumaaya upakaranangalilonn. madhya-cretatius kaalayalavil maraine (planctonic/benthik) foraminifera, bulk carbonate isotope anupathangal ennivayekkurichulla padanangal soochippikkunnathu ~ 100 Ma muthal 66 Ma vareyulla thudarchayaaya thaapana kaalayalavaanu. eee kaalayalavil, thekkan uyarnna akshamshangal athra thanuppullathum athra choodullathumaayirunnu. nannayi samrakshikkappetta brachiopod, molascan shellukalude ooksijan isotope vishakalanathil ninnaan cretatius vadakkan uyarnna akshaamshangalude paaliyodempecharukal kanakkaakkiyath. padanangalil ninnulla phalangal thaapanilayile ettakkurachilukal kaanikkunnath seasonal vyathiyanavumaayi poruthappedunnu.
cretatius marathekkurichulla dendrocronology.
bhoomiyile vividha bhoomishaasthraparamaaya sthalangalil kaalavastha enganeyaayirikkumennathi vishadaamshangalum cretatius samayat valarchaa valaya alavukal nalkaan kazhiyum. cretatius phoosil vanangalil ninnulla vruksha valayangalude allengil valarchaa valayangalude paatten vishakalanam pradhaanamaayum paaliyoklaimettu, vanaa ulppaadanakshamatha ennivayilekku nigamanangal undakkaan upayogikkunnu. vrukshavalarcha ring datinginu upayogikkunna valare upayogapradamaaya oru shaasthreeya reethiyaanu dendrocronology. ennirunnaalum, phoosil maratthil nadatthiya mikka padanangalum munkaalangalil pravarthichirunna vrukshavalarchaa nirakkumayi bandhapetta prakriyakal varthamaanakaalathe ekeekrithathvathil pravartthikkunna prakriyakalkku samanamaanenna ashayathe aasrayichirikkunnu. eee adisthaanathil, cretatius marangalile valarchaa valayangalude vishakalanathil ninnu vanaa uthppaadanakshamatha anumanikkaan kazhiyum. kritteshyasil ninnulla vanaa uthppaadanakshamathayude vishakalanam kaanikkunnath kuranja paaliyoletyoodukalil vaarshika vruksha valarchaa nirakk innathe apekshichu ganyamaayi uyarnnathaan. dhruva paleolettityoodukal, valarchaa nirakk vishakalanam uyarnna uthppaadanakshamathaye soochippikkunnu, pakshe innathe apekshichu kooduthal ganyamaayi mechappettu. uyarnna paaliyoletyoodukalil ninnulla phoosil cheytha thadi valarchaa valayangalude dendrocronology eee kaalayalavil aagola thalatthil harithagriham polulla kalavastha saahacharyangalude saannidhyam soochippikkunnu.