Pumice kana pumice imhando yedombo rine ruvara rwakareruka, rine furo rakagadzirwa negirazi-akavharidzirwa mabhururu, uye rinowanzonzi silicate volcanic glass.
Matombo aya anoumbwa neacidic magma nekuita kwekuputika kwegomo kunoburitsa zvinhu mumhepo; wobva wafamba wakachinjika uye uunganidze sedombo re pyroclastic.
Pumice ine yakakwira versicular properties, ine nhamba huru yemasero (cellular structure) nekuda kwekuwedzera kwefuro rechisikigo ririmo, uye rinowanzowanikwa sechinhu chakasununguka kana zvidimbu muvolcanic breccia. Nepo zvicherwa zviri mupumice zviri feldspar, quartz, obsidian, cristobalite, uye tridymite.
Pumice inoitika apo acidic magma inokwira kumusoro uye kamwe kamwe inosangana nemhepo yekunze. Yechisikigo girazi furo rine / gasi ririmo rine mukana wekupukunyuka uye magma inotonhora kamwe-kamwe, pumice inowanzovapo sezvimedu zvinoburitswa panguva yekuputika kwegomo rinobva pakukura kusvika kumatombo.
Pumice inowanzoitika sekunyunguduka kana kumhanya, zvinhu zvakasununguka kana zvidimbu mumakomo anoputika.
Pumice inogonawo kugadzirwa nekupisa obsidian, kuitira kuti gasi ripukunyuke. Kupisa kunoitwa pane obsidian kubva kuKrakatoa, tembiricha inodiwa kushandura obsidian kuita pumice avhareji 880oC. Iyo chaiyo giravhiti ye obsidian iyo yekutanga yaive 2.36 yakadonha kusvika 0.416 mushure mekurapwa, saka inoyangarara mumvura. Iri dombo repumice rine hydraulic properties.
Pumice ichena kusvika kune grey, yero kusvika kutsvuku, vesicular texture ine orifice size, iyo inosiyana maererano kune imwe neimwe kana kuti kwete kune yakatsva chimiro ine oriented orifices.
Dzimwe nguva gomba rinozadzwa ne zeolite/calcite. Iri dombo rinoshingirira nedova rinotonhora (chando), kwete hygroscopic (inosveta mvura). Ane low heat transfer properties. Kudzvinyirira simba pakati pe30 – 20 kg / cm2. Iko kuumbwa kukuru kweamorphous silicate minerals.
Zvichienderana nemaitiro ekuumbwa (kudhirowa), kugoverwa kwehukuru hwechikamu (chidimbu) uye zvinhu zvekwakabva, pumice deposits inoiswa sezvizvi:
Sub-nzvimbo
Sub-aqueous
New ardante; i.e. madhipoziti akaumbwa neakatwasuka kubuda kwegasi mumabota, zvichikonzera musanganiswa wezvidimbu zvehukuru hwakasiyana mune fomu yematrix.
Mhedzisiro yekudzoreredza dhipoziti (redeposit)
Kubva pakuchinja kwemamiriro ekunze, nzvimbo dzinenge dzine kuputika kwemakomo chete dzichava nehupfumi hwepumice deposits. Nguva yegeological yemadhipoziti aya iri pakati peTertiary neazvino. Makomo anoputika aipisa mukati menguva iyi ye geological aisanganisira mupendero wePacific Ocean uye nzira inobva kuGungwa reMediterranean kuenda kuHimalayas uyezve kuEast India.
Matombo akafanana nemamwe pumice pumicite uye volcanic cinder. Pumicite ine makemikari akafanana, mabviro ekuumbwa uye girazi chimiro sepumice. Musiyano unongova muhukuru hwechidimbu, iyo idiki pane masendimita gumi nematanhatu mudhayamita. Pumice inowanikwa iri padyo nenzvimbo yayakabva, nepo pumicite yakatakurwa nemhepo kwechinhambwe chakati wandei, uye yakaiswa muchimiro chekuunganidzwa kwedota rakatsetseka kana se tuff sediment.
The volcanic cinder ine zvidimbu zvitsvuku kusvika kune zvitema vesicular zvidimbu, izvo zvakaiswa panguva yekuputika kwedombo rebasaltic kubva mukuputika kwegomo. Mazhinji emadhipoziti ecinder anowanikwa sezvimedu zvekurara zvakakoniwa kubva pa 1 inch kusvika masendimita akati wandei mudhayamita.
Kugona kweIndonesian Pumice
MuIndonesia, kuvapo kwepumice kunogara kwakabatana nenhevedzano yeQuaternary kusvika kuTertiary volcanoes. Kugoverwa kwayo kunobata nzvimbo dzeSerang neSukabumi (West Java), chitsuwa cheLombok (NTB) uye chitsuwa cheTernate (Maluku).
Iko kugona kwepumice deposits ine kukosha kwehupfumi uye nzvimbo dzakakura kwazvo dziri pachitsuwa cheLombok, West Nusa Tenggara, Ternate Island, Maluku. Huwandu hwematura akayerwa munzvimbo iyi anofungidzirwa kupfuura mamirioni gumi ematani. Munharaunda yeLombok, kushandiswa kwepumice kwave kuchiitwa kubva makore mashanu apfuura, nepo muTernate kushandiswa kwakangoitwa muna 1991.