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. Inā noho mānoanoa a paʻa, hiki iā ia ke hana i nā pōhaku e like me ka tuff. 2. Lapilli: ka nui 2–64 mm. Me ke ʻano o ka ʻiliʻili, hiki ke lilo i mau ʻāpana pōhaku a i ʻole nā kulu o ka magma paʻa wikiwiki. 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 ʻana o 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
ʻO ka hapa nui o nā pōhaku pyroclastic i hana ʻia mai ka lehu pele.Hiki i ka Tuff ke maikaʻi a i ʻole ke ʻano ʻāwiliwili, ma muli o ka hui ʻana o nā nui. 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.
