Ososayensi bakholelwa ukuthi bathole umthombo “womgodi wamandla adonsela phansi” ojulile e-Indian Ocean, indawo eyinqaba lapho amandla adonsela phansi oMhlaba ephansi kunakwezinye izindawo zomhlaba wethu.
I-Indian Ocean geoid low (IOGL) iyi-depression engu-1.2 million-square-mile (3 million-square-kilometer) e-Indian Ocean 746 miles (1,200 km) eningizimu-ntshonalanga ye-India. Amandla adonsela phansi aphansi abuthakathaka kakhulu uma kuqhathaniswa nendawo eyizungezile kangangokuthi ungqimba lwamanzi alo lumuncwe, okushiya izinga lolwandle phezu komgodi ngamamitha angu-348 ngaphansi kunesilinganiso somhlaba wonke.
Okuphansi kuwumphumela weplanethi yethu ene-squidgy ngokumangalisayo, eqhwalela ezigxotsheni, amaqhuqhuva enkabazwe, futhi iguqe phakathi kwezigaxa namaqhuqhuva ebusweni bayo. Kodwa selokhu yatholakala ngo-1948, umsuka walo mgodi wakwa-Indian Ocean uye wadida ososayensi.
Manje, ucwaningo olushicilelwe ngoMeyi 5 kujenali Izincwadi Zokucwaninga Zezepolitiki iphakamisa ukuthi i-IOGL idalwe i-low-density magma eyadudulelwa olwandle i-Indian ngezitshebe ezicwilayo zolwandle lwasendulo.
Ngokocwaningo, umsuka wale geoid low ube yindida. Kwabekwa amathiyori ahlukene ukuze achaze lokhu kuphazamiseka kwe-geoid okungekuhle. Kodwa-ke, zonke lezi zifundo zibheke ukungahambi kahle kwanamuhla futhi zazingakhathazeki ngokuthi le geoid low yaba khona kanjani.
Ukufuna impendulo engaba khona, abacwaningi basebenzise amamodeli wekhompiyutha ayi-19 alingisa ukunyakaza kwamapuleti e-mantle kanye ne-tectonic esifundeni eminyakeni eyizigidi eziyi-140. Babe sebeqhathanisa okuphansi okulingiswayo okwakheke esivivinyweni ngasinye negobongo lempilo yangempela.
Amamodeli ayisithupha alingisa kangcono i-geoid yangempela ephansi abelane ngesici esisodwa esivamile: ama-plues of hot, low-density magma akhuphuke ukuze asuse indawo yokuminyana okuphezulu ngaphansi kokuphansi, ehlisa isisindo sesifunda futhi enze amandla adonsela phansi abe buthaka.
Lawa ma-plums amatshe ama-mantle avela endaweni ephazamisayo engamakhilomitha angu-600 entshonalanga ngaphansi kwe-Afrika. Eyaziwa ngokuthi “isiqu sase-Afrika,” igwebu eliminyene lezinto ezicwebezelayo ngaphakathi kwengubo yase-Afrika lilingana nezwekazi futhi lide ngokuphindwe izikhathi eziyikhulu kune-Mount Everest.
Kodwa yini ebingaphusha izingcezu zale nto ngaphansi koLwandlekazi i-Indian? Izingcezu zokugcina zephazili ye-tectonic "ama-slabs e-Tethyan," noma izinsalela zaphansi kolwandle kusukela olwandle lwasendulo lwase-Tethys, olwalukhona phakathi kwezwekazi elikhulu i-Laurasia ne-Gondwana eminyakeni engaphezu kwezigidi ezingu-200 edlule.
Ngokusho kwabacwaningi, njengoba ipuleti laseNdiya lihlukana neGondwana laphinde lashayisana ne-Eurasian plate, lahamba phezu kwepuleti iTethys, lalehlisa lalifaka ngaphansi kwepuleti laseNdiya. Izingcezwana eziphukile ze-Tethys Ocean endala zaqala ukushona zijula ku-mantle engezansi njengoba zishayelwa ku-mantle eduze ne-East Africa yanamuhla.
Cishe eminyakeni eyizigidi ezingu-20 edlule, izingcwecwe ze-Tethyan ezicwilayo zanyakaza enye ye-magma evaleleke e-Afrika, kwakheka amaphuphu.
"Lawa ma-plums, kanye nesakhiwo se-mantle eduze ne-geoid low, anesibopho sokwakheka kwalesi sidididi esibi se-geoid," kubhala abacwaningi.
Ukuqinisekisa izibikezelo zabacwaningi, ososayensi manje bazodinga ukwembula ukuba khona kwamapayipi besebenzisa idatha yokuzamazama komhlaba eqoqwe kusuka endaweni ephansi ye-geoid. Ukuthi ama-plums ayimpendulo yangempela, noma amandla ajulile adlalayo, kusazobonakala.
Ucwaningo lwashicilelwa ekuqaleni kujenali Izincwadi Zokucwaninga Zezepolitiki ngoMeyi 5, 2023.
