He aha nā Pōhaku Pyroclastic a pehea lākou i hana ʻia ai?
ʻO nā pōhaku Pyroclastic kekahi o nā "moʻolelo" maopopo loa o ka ikaika o ka hana pele. Ke pahū ka lua pele, ʻaʻole nā mea a pau i hoʻokuʻu ʻia e kahe ana ma ke ʻano he pele. Nui nā pele e luaʻi maoli i nā ʻāpana pōhaku, lehu, a me nā ʻāpana magma i hoʻokuʻu ʻia i ka lewa, a laila hāʻule hou i lalo a hōʻiliʻili. A laila hiki i kēia mau waihona ke hana i nā pōhaku pyroclastic. No ka hoʻomaopopo ʻana i nā pōhaku pyroclastic, pono mākou e nānā i ko lākou pilina pili i ke ʻano o ka pele, ka nui o ka mea i hoʻokuʻu ʻia, pehea e lawe ʻia ai kēlā mea, a pehea e "paʻa" ai i loko o ka pōhaku paʻa.
Ka wehewehe ʻana o nā pōhaku pyroclastic
I ka ʻōlelo maʻalahi, ʻo nā pōhaku pyroclastic he mau pōhaku i hana ʻia mai nā mea pele i hoʻokuʻu ʻia i ka wā o nā pahū pahū (bursting eruptions), a laila e noho a hana i ka compaction a me ka cementation (lithification). Loaʻa ka huaʻōlelo "pyroclastic" mai ka Helene mai: pyro (ahi) a me klastos ('āpana). No laila, hiki ke wehewehe ʻia ka pyroclastic ʻo "fragmentation resulted from fire/volcanic activity."
ʻAʻole e like me nā pōhaku igneous extrusive e like me ka basalt a i ʻole andesite, i hoʻokumu ʻia i ka wā e kahe ai ka pele a laila paʻa, ua hoʻokumu ʻia nā pōhaku pyroclastic mai nā ʻāpana i loaʻa mai nā pahū ʻana—ʻo ia hoʻi nā ʻāpana magma e paʻa ana i ka lewa, a i ʻole nā ʻāpana pōhaku kahiko mai ke kino pele i haki ʻia a hoʻolei ʻia aku.
Nā mea hana: mai ka lehu a i nā pōkā pele
Ua kapa ʻia nā mea Pyroclastic he pyroclasts. ʻOkoʻa loa ka nui o nā Pyroclasts, a kōkua ka hoʻokaʻawale ʻana i ka nui i nā geologists e ʻike i ke ʻano o ka waiho ʻana a me ka pōhaku:
1. Lehu pele (lehu): ka nui < 2 mm. Hiki i ka lehu ke lahilahi loa, lawe maʻalahi ʻia e ka makani, a hiki ke uhi i nā wahi nui. Ke waiho mānoanoa a paʻa, hiki iā ia ke hana i nā pōhaku e like me ka tuff. 2. Lapilli: ka nui 2–64 mm. ʻAno like me ke one, hiki ke lilo i mau ʻāpana pōhaku a i ʻole nā kulu o ka magma paʻa koke. Hiki i nā waihona i hoʻomalu ʻia e nā lapilli ke hana i ka lapilli tuff a i ʻole ka pōhaku pyroclastic waena.
3. Nā pōkā a me nā poloka pele: ka nui > 64 mm.– ʻO ka maʻamau, he palakiko nō nā pōkā pele ke hoʻolei ʻia, no laila hiki ke poepoe a aerodynamic paha ko lākou ʻano.
– ʻO nā poloka maʻamau he mau ʻāpana pōhaku paʻa i hoʻolei ʻia, ʻoi aku ke kihi o ko lākou ʻano.
Hiki i nā waihona ʻōpala e like me kēia ke hana i nā pyroclastic breccias.
Ma waho aʻe o ka nui, hiki ke hoʻokaʻawale ʻia nā pyroclasts e ko lākou kumu:
– ʻŌpio: mea i puka mai i ka magma hou (e.g. pumice, scoria).
– Lithic: nā ʻāpana pōhaku kahiko mai nā paia o ka lua pele a i ʻole nā kahawai pele.
– Nā kristal: nā ʻāpana mineral (e.g. plagioclase, pyroxene) i hoʻokuʻu ʻia mai ka magma.
Pehea e hana ʻia ai nā pōhaku pyroclastic?
ʻO ke kūkulu ʻia ʻana o nā pōhaku pyroclastic he moʻo o nā kaʻina hana: ka pelehū → ka lawe ʻana → ka waiho ʻana → ka lithification. Eia nā pae.
1) Nā mea hoʻonāukiuki no nā pahū pahū: kaomi kinoea a me ka mānoanoa o ka magma
ʻO ka maʻamau, hana ʻia nā pahū pahū i ka wā e nui ai ke kinoea (ka mahu wai, CO₂, SO₂) i ka magma a/a i ʻole ka mānoanoa lawa e hiki ai i ke kinoea ke pakele mālie. ʻO ka hopena, piʻi aʻe ke kaomi, e alakaʻi ana i ka pahū. Nahā ka magma i loko o nā ʻāpana liʻiliʻi i ka wā e hoʻonui koke ai ke kinoea—e like me ka lūlū ʻana i kahi kini soda a laila wehe iā ia, akā ma kahi pae nui a ma nā mahana kiʻekiʻe loa.
Hoʻopuka kēia kahua i nā mea e like me ka lehu pele, lapilli, pumice, scoria, bombs, a me nā poloka. ʻO kēia nā mea maka mua no nā pōhaku pyroclastic.
2) Ka hoʻokuke ʻana a me ka lawe ʻana: hāʻule ma ke ʻano he lehu a heheʻe paha ma ke ʻano he kahe pyroclastic.
Ke hoʻokumu ʻia, neʻe nā pyroclasts ma kekahi mau ʻano:
– Hāʻule Pyroclastic
Hoʻolei ʻia nā mea i ka lewa a laila hāʻule ma muli o ke koʻikoʻi. Hiki ke lawe ʻia ka lehu maikaʻi e nā makani no nā haneli kilomita, ʻoiai e hāʻule kokoke ana nā lapilli a me nā pōkā i ke kikowaena o ka pele. Hoʻonohonoho pono ʻia nā waihona hāʻule a uhi i ka ʻili.
– Nā au o ka nui o ka pyroclastic
He mau hui wela loa kēia o ke kinoea, ka lehu, a me nā ʻāpana pōhaku e kahe wikiwiki ana i lalo o nā pali—me ka wikiwiki a me ka hiki ke make. ʻOi aku ka nui o nā waihona (ʻaʻole i hoʻonohonoho pono ʻia), hiki ke uhi i nā awāwa a me nā pāpū, a pinepine e hana i nā waihona nui.
– Ka piʻi ʻana o ka Pyroclastic
Hiki i nā nalu pyroclastic dilute a turbulent ke lanakila ma luna o nā pale topographic. Hōʻike pinepine kā lākou mau waihona i nā ʻano sedimentary e like me ke cross-lamination.
Hoʻohuli kēia ʻano o ka lawe ʻana i ke ʻano hope loa o ka pōhaku: inā paha he papa lahilahi, nui, māka ʻia, a i ʻole he hui "random" o nā nui.
3) Sedimentation: hōʻiliʻili i loko o nā papa mānoanoa
I ka hala ʻana o ka manawa, hōʻiliʻili nā pyroclasts i loko o nā waihona. Hiki i nā waihona ke loaʻa i kekahi mau kenimika a i ʻumi mika ka mānoanoa, ma muli o ka nui a me ka wahi o ka pele. Hiki i nā waihona ke hoʻopiha i nā kīʻaha, ālai i nā muliwai, a hana paha i nā pāpū hou. I loko o kēia wā, ua palupalu mau ka mea (like me ke one, ka ʻiliʻili, a i ʻole ka lehu).
4) Lithification: mai ka lepo palupalu a i ka pōhaku paʻa
I mea e lilo ai i pōhaku, pono e hana ʻia nā waihona pyroclastic i ka lithification ma o:
– Ka hoʻopili ʻana: kaomi ke kaumaha mai ka papa ma luna ma luna o ka lepo i mea e hoʻēmi ʻia ai nā pores.
– Cementation: nā minelala e hoʻopili ʻia mai ka wai (e like me ka silica, calcite, zeolite, clay) e "hoʻopili" i nā ʻano palaoa.
– Kuʻihao ʻana ma kekahi mau waihona wela: Inā hāʻule a kahe paha ka waihona i ka wā wela loa, hiki i nā ʻāpana o ke aniani pele ke pipili a hui pū. Hoʻopuka kēia i kahi tuff i hoʻopaʻa ʻia a paʻa loa (ignimbrite).
Hiki ke hana wikiwiki ʻia ke kaʻina hana o ka lithification ma kahi pae honua, ʻoiai inā mānoanoa, wela, a kanu koke ʻia nā waihona.
Nā ʻano maʻamau o nā pōhaku pyroclastic
Eia kekahi mau ʻano i loaʻa pinepine ʻia:
1. ʻO Tuff
Pōhaku Pyroclastic i haku ʻia me ka lehu pele. Hiki i ka Tuff ke maikaʻi a ʻāwili iki paha, ma muli o ka nui o ka hui ʻana. Hoʻohana nui ʻia ka Tuff ma ke ʻano he mea kūkulu hale ma nā wahi he nui, ʻoiai ʻokoʻa kona ikaika.
2. Hoʻā ʻā (ignimbrite)
ʻO ka mea maʻamau i loaʻa mai nā waihona kahe pyroclastic i hoʻomehana nui ʻia me ka lehu, pinepine me kahi ʻano i hoʻopili ʻia, hiki i nā ignimbrites ke hana i nā pāpū ākea a lawelawe ma ke ʻano he mau māka o nā pele nui.
3. Nā breccia Pyroclastic
Hana ʻia me nā ʻāpana kihi nui (nā poloka) a i ʻole ka hui ʻana o nā ʻāpana nui i loko o kahi matrix lehu/lapilli. Hōʻike i kahi pahū a hiolo paha e hana ana i nā ʻāpana nui.
4. ʻO ka ʻōpala Lapilli
ʻO ka tuff waiwai i ka Lapilli (nā hua 2-64 mm). ʻIke ʻia ke ʻano he "mottled" no ka mea ua hoʻokomo ʻia nā ʻāpana nui i loko o kahi matrix lehu.
No ke aha he mea nui e aʻo i nā pōhaku pyroclastic?
He mea nui nā pōhaku Pyroclastic no ka mea:
– No ke hoʻopaʻa ʻana i ka mōʻaukala o nā pele ʻana: mai ka nui o nā ʻāpana, ka haku mele ʻana, a me ke ʻano o nā papa, hiki i nā kānaka ʻepekema honua ke wehewehe i ke ʻano o ka pele a me kona nui.
– Ke kōkua ʻana i ka palapala ʻāina pōʻino o ka lua pele: hōʻike nā waihona kahe pyroclastic a me ka hāʻule ʻana o ka lehu i nā wahi i hoʻopilikia ʻia a hiki ke hoʻopilikia hou ʻia.
– He mea pono ma ke ʻano he kumuwaiwai: lilo kekahi mau waihona pyroclastic i mau aquifers, minerals, a i ʻole nā pōhaku ʻoihana; akā hiki iā lākou ke palupalu a maʻalahi i ka ʻāina hāʻule i ka wā e ʻino ai.
Pani
ʻO nā pōhaku Pyroclastic nā pōhaku i hoʻokumu ʻia mai nā ʻāpana o nā mea pele i loaʻa mai nā pahū pahū. ʻO kēia mau mea—mai ka lehu a me ka lapilli a hiki i nā pōkā a me nā poloka—e lawe ʻia e ka lehu a i ʻole nā kahe pyroclastic, a laila e noho, hoʻopaʻa, sima, a i kekahi manawa e hoʻopili ʻia ma muli o ka wela, a laila e hana i nā pōhaku paʻa e like me ka tuff, ignimbrite, a me ka pyroclastic breccia. Ma ke aʻo ʻana i nā pōhaku pyroclastic, ʻaʻole mākou e hoʻomaopopo wale i nā kaʻina hana geological e hoʻopili ana i ka ʻili o ka Honua akā hiki nō hoʻi ke hahai i nā kaha o nā pahū i hala e wānana i nā pilikia e hiki mai ana.
Inā makemake ʻoe, hiki iaʻu ke hoʻololi i kēia ʻatikala no nā pono kula (maʻalahi), koleke (ʻoi aku ka loea), a i ʻole e hoʻohui i nā laʻana o nā pōhaku pyroclastic i loaʻa ma Indonesia me ko lākou mau wahi a me nā ʻano.
