Geology ntawm Mount Everest

2024 Tus sau: Cyrus Reynolds | [email protected]. Kawg hloov kho: 2024-02-08 04:17

Lub Himalayan ntau yam, topped los ntawm 29, 035-foot Mount Everest, lub roob siab tshaj plaws nyob rau hauv lub ntiaj teb no, yog ib tug ntawm cov loj tshaj plaws thiab feem ntau sib txawv thaj chaw nyob rau hauv lub ntiaj teb no nto. Qhov ntau, khiav sab qaum teb mus rau sab qab teb sab hnub tuaj, ncav 1,400 mais; nws txawv ntawm 140 mais thiab 200 mais dav; hla los yog abuts tsib lub teb chaws sib txawv-Is Nrias teb, Nepal, Pakistan, Bhutan, thiab cov neeg koom pheej ntawm Tuam Tshoj; yog leej niam ntawm peb tus dej loj - Indus, Ganges, thiab Tsampo-Bramhaputra; thiab khav tshaj 100 lub roob uas siab tshaj 23, 600 ko taw.

Kev tsim ntawm Himalayas

Geologically hais, lub Himalayas thiab Mount Everest kuj tseem hluas. Lawv tau pib tsim ntau dua 65 lab xyoo dhau los thaum ob lub ntiaj teb cov phiaj xwm loj-lub phaj Eurasian thiab Indo-Australian phaj sib tsoo. Indian subcontinent tau tsiv mus rau sab qaum teb sab hnub tuaj, tsoo rau Asia, folding thiab thawb lub phaj ciam teb kom txog rau thaum lub Himalayas tau tshaj tsib mais siab. Lub phaj Indian, txav mus rau pem hauv ntej li 1.7 ntiv tes hauv ib xyoos, tau maj mam thawb hauv qab lossis tshem tawm los ntawm Eurasian phaj, uas tsis kam txav mus los. Yog li ntawd, lub Himalayas thiab Tibetan Plateau txuas ntxiv nce li 5 mus rau 10 millimeters txhua xyoo. Geologists kwv yees tias Is Nrias teb yuav txuas ntxiv mus rau sab qaum teb mus yuav luag ib txhiab mais ntawm 10 tom ntejlab xyoo.

Peak Tsim thiab Fossils

Raws li ob daim phiaj sib tsoo, pob zeb hnyav dua raug thawb rov qab mus rau hauv lub ntiaj teb lub tsho tiv no ntawm qhov sib chwv. Lub caij no, cov pob zeb sib zog xws li limestone thiab sandstone raug thawb mus rau pem hauv ntej los ua cov roob siab. Nyob rau sab saum toj ntawm lub ncov siab tshaj plaws, zoo li Mount Everest, nws muaj peev xwm nrhiav tau 400-million-xyoo-laus fossils ntawm hiav txwv creatures thiab shells uas tau muab tso rau hauv qab ntawm qhov dej ntiav dej hiav txwv. Tam sim no cov pob txha raug nthuav tawm ntawm lub ru tsev ntawm lub ntiaj teb, tshaj 25,000 feet saum hiav txwv theem.

Marine Limestone

Lub ncov ntawm Mount Everest yog tsim los ntawm cov pob zeb uas ib zaug submerged hauv qab Tethys Hiav Txwv, ib txoj kev qhib dej uas muaj nyob nruab nrab ntawm Indian subcontinent thiab Asia tshaj 400 lab xyoo dhau los. Rau tus kws sau ntawv zoo John McPhee, qhov no yog qhov tseeb tshaj plaws ntawm lub roob:

Thaum cov neeg nce toj xyoo 1953 tau cog lawv cov chij rau ntawm lub roob siab tshaj plaws, lawv tau muab tso rau hauv cov daus saum cov pob txha ntawm cov tsiaj uas tau nyob hauv dej hiav txwv sov so uas Is Nrias teb, txav mus rau sab qaum teb, tawm mus. Muaj peev xwm ntau npaum li nees nkaum txhiab ko taw hauv qab dej hiav txwv, cov pob txha pob txha tau hloov mus ua pob zeb. Qhov no yog ib qho tseeb yog ib tug treatise nyob rau hauv nws tus kheej nyob rau hauv lub zog ntawm lub ntiaj teb no. Yog hais tias los ntawm ib co fiat kuv yuav tsum tau txwv tag nrho cov no sau rau ib kab lus, qhov no yog qhov kuv yuav xaiv: qhov ua siab tshaj ntawm Mt. Everest yog marine limestone.

Sedimentary Layers

Cov pob zeb sedimentary pom ntawm Mount Everest suav nrog limestone, marble, shale, thiab pelite; hauv qab no lawv laus lawmpob zeb suav nrog granite, pegmatite intrusion, thiab gneiss, pob zeb metamorphic. Lub sab sauv ntawm Mount Everest thiab cov neeg nyob sib ze Lhotse muaj cov pob txha hauv hiav txwv.

Main Rock Formations

Mount Everest yog tsim los ntawm peb lub pob zeb sib txawv. Los ntawm lub roob hauv paus mus rau qhov ua siab tshaj, lawv yog: Rongbuk Tsim; North Col Formation; thiab Qomolangma Formation. Cov pob zeb no tau sib cais los ntawm qhov tsis zoo ntawm lub kaum sab xis, yuam txhua tus dhau los ntawm tus qauv zigzag.

Lub Rongbuk Tsim muaj xws li cov pob zeb hauv qab daus hauv qab Mount Everest. Cov pob zeb metamorphic suav nrog schist thiab gneiss, ib pob zeb zoo nkauj. Intruded ntawm cov qub pob zeb txaj yog cov zoo sills ntawm granite thiab pegmatite dikes qhov twg molten magma ntws mus rau hauv cov kab nrib pleb thiab solidified.

Lub complex North Col Formation, uas pib txog 4.3 mais ntawm lub roob, muab faib ua ob peb ntu. Sab qaum yog lub npe Yellow Band, lub pob zeb daj-xim av ntawm marble, phyllite nrog muscovite thiab biotite, thiab semischist, me ntsis metamorphosed sedimentary pob zeb. Cov pab pawg kuj muaj cov pob txha ntawm crinoid ossicles, cov kab mob hauv hiav txwv nrog cov pob txha. Hauv qab ntawm Yellow Band yog alternating txheej ntawm marble, schist, thiab phyllite. Sab hauv qab yog tsim los ntawm ntau yam schists ua los ntawm metamorphosed limestone, sandstone, thiab av nkos. Nyob rau hauv qab ntawm qhov tsim yog Lhotse detachment, ib tug thrust txhaum uas faib North Col Formation los ntawm lub hauv paus Rongbuk Formation.

Qomolangma Tsim, ntu siab tshaj ntawm pob zeb ntawm qhov ua siab tshajPyramid ntawm Mount Everest, yog ua los ntawm txheej ntawm Ordovician-hnub limestone, recrystallized dolomite, siltstone, thiab laminae. Txoj kev tsim pib txog 5.3 mais ntawm lub roob ntawm thaj tsam txhaum cai saum North Col Formation, thiab xaus rau ntawm qhov ua siab tshaj. Cov txheej sab saud muaj ntau cov pob txha hauv hiav txwv, suav nrog trilobites, crinoids, thiab ostracods. Ib txheej 150-ko taw nyob rau hauv qab ntawm qhov ua siab tshaj pyramid muaj cov seem ntawm cov kab mob, suav nrog cyanobacteria tso rau hauv dej ntiav ntiav.