I-Pumice okanye i-pumice luhlobo lwelitye elikhanyayo ngombala, liqulethe igwebu elenziwe ngamaqamza eglasi, kwaye lidla ngokubizwa ngokuba yi-silicate volcanic glass.
La matye enziwa yi-acidic magma ngesenzo sogqabhuko-dubulo lwentaba-mlilo olukhuphela izinto emoyeni; emva koko uthuthelwe ngokuthe tye kwaye uqokelele njengelitye le-pyroclastic.
I-Pumice ineempawu eziphezulu ze-versicular, iqulethe inani elikhulu leeseli (isakhiwo seselula) ngenxa yokwandiswa kwe-foam yegesi yendalo equlethwe kuyo, kwaye ngokuqhelekileyo ifunyenwe njengento ekhululekile okanye iziqhekeza kwi-volcanic breccia. Ngelixa amaminerali aqulethwe kwi-pumice yi-feldspar, i-quartz, i-obsidian, i-cristobalite, kunye ne-tridymite.
I-Pumice yenzeka xa i-acidic magma inyukela phezulu kwaye ngequbuliso idibane nomoya wangaphandle. I-foam yeglasi yendalo kunye / igesi equlethwe kuyo inethuba lokubaleka kwaye i-magma iqandusela ngokukhawuleza, i-pumice ihlala ikhona njengamaqhekeza akhutshiweyo ngexesha logqabhuko-mlilo ukusuka kubukhulu ukusuka kwigrabile ukuya kumatye.
I-Pumice ikholisa ukuvela njengokunyibilika okanye ukubaleka, imathiriyeli eshukumayo okanye amaqhekeza kwi-volcanic breccias.
I-Pumice inokwenziwa ngokufudumeza i-obsidian, ukuze igesi ibaleke. Ukufudumeza okwenziwe kwi-obsidian ukusuka eKrakatoa, ubushushu obufunekayo ukuguqula i-obsidian ibe yi-pumice ephakathi kwama-880oC. Ubunzima obuthile be-obsidian eyayiyi-2.36 ekuqaleni yehla kwi-0.416 emva konyango, ngoko ke iyadada emanzini. Eli litye lepumice lineempawu zehydraulic.
I-Pumice imhlophe ukuya kwengwevu, i-yellowish ukuya ebomvu, i-vesicular texture kunye nobukhulu be-orifice, eyahluka ngokumalunga nomnye okanye kungekhona kwisakhiwo esitshisiweyo esine-orifices ejoliswe kuyo.
Ngamanye amaxesha umngxuma uzaliswe zeolite / calcite. Eli litye liyamelana nombethe (iqabaka) eliqhaqhazelisa amazinyo (iqabaka), hayi i-hygroscopic (amanzi afunxayo). Ineempawu zokuhambisa ubushushu obuphantsi. Amandla oxinzelelo phakathi kwe-30 – 20 kg / cm2. Ukubunjwa okuphambili kweeminerali ze-amorphous silicate.
Ngokusekelwe kwindlela yokwakheka (i-deposition), ukuhanjiswa kobungakanani beqhekeza (iqhekeza) kunye nezinto ezivela kwimvelaphi, iidiphozithi zepumice zihlelwa ngolu hlobo lulandelayo:
Indawo engaphantsi
I-Sub-aqueous
I-ardante entsha; oko kukuthi iidiphozithi ezenziwe ngokuphuma okuthe tye kwegesi kwi-lava, okukhokelela kumxube weeqhekeza ezinobungakanani obahlukeneyo kwifom ye-matrix.
Isiphumo sokudipozithwa kwakhona (idiphozithi kwakhona)
Ukusuka kwi-metamorphosis, kuphela iindawo ezinentaba-mlilo kuphela eziya kuba neediphozithi zoqoqosho lwepumice. Ixesha lokwakheka komhlaba kwezi deposits liphakathi kweTertiary nelangoku. Iivolcano ezazikho ngeli xesha lokwakheka komhlaba zibandakanya umda woLwandlekazi lwePasifiki kunye nendlela esuka kuLwandle lweMeditera ukuya kwiiHimalaya ukuya kutsho eMpuma Indiya.
Amatye afana nezinye iipumice yipumicite kunye ne-volcanic cinder. I-Pumicite inokwakheka kweekhemikhali ezifanayo, imvelaphi yokwakheka kunye nesakhiwo seglasi njengepumice. Umahluko kuphela kwisayizi yamasuntswana, encinci kune-intshi ezili-16 ububanzi. I-Pumice ifunyenwe ngokuthelekiswa nendawo eyavela kuyo, ngelixa i-pumicite iye yahanjiswa ngumoya umgama omde, kwaye yafakwa ngohlobo lokuqokelelwa kothuthu okanye njengentlenga ye-tuff.
I-volcanic cinder inamaqhekeza abomvu ukuya kwi-vesicular emnyama, afakwe ngexesha logqabhuko lwelitye le-basaltic ukusuka kugqabhuko lwentaba-mlilo. Uninzi lweediphozithi ze-cinder zifumaneka njengamaqhekeza e-conical okulala ukusuka kwi-intshi enye ukuya kwii-intshi ezininzi ububanzi.
Ukubakho kwePumice yaseIndonesia
E-Indonesia, ubukho be-pumice buhlala bunxulunyaniswa nochungechunge lwe-Quaternary ukuya kwii-volcano ze-Tertiary. Ukusasazwa kwayo kuhlanganisa iindawo zaseSerang naseSukabumi (eNtshona yeJava), isiqithi saseLombok (NTB) kunye nesiqithi saseTernate (Maluku).
Amandla ediphozithi epumice anokubaluleka kwezoqoqosho kunye noovimba abakhulu kakhulu kwisiqithi saseLombok, eNtshona Nusa Tenggara, kwisiqithi saseTernate, eMaluku. Isixa soovimba abalinganisiweyo kwindawo siqikelelwa ngaphezulu kwe-10 lezigidi zeetoni. Kwindawo yaseLombok, ukusetyenziswa kwepumice kuye kwaqhutywa ukususela kwiminyaka emihlanu eyadlulayo, ngelixa e-Ternate ukuxhaphazwa kwenziwa kuphela kwi-1991.