Liparite (rhy­o­lite). Char­ac­ter­is­tics, dis­tri­b­u­tion, appli­ca­tion

Liparite (rhy­o­lite) is a vol­canic rock formed by the solid­i­fi­ca­tion of acidic mag­ma on the Earth­’s sur­face or in near-sur­face con­di­tions.

The use of the term “liparite (rhy­o­lite)” is explained by the fact that these two terms are often used as syn­onyms in geol­o­gy, although they have cer­tain his­tor­i­cal and con­tex­tu­al dif­fer­ences. Liparite is an obso­lete name for a rock that was wide­ly used in the 19th and 20th cen­turies, espe­cial­ly in Euro­pean lit­er­a­ture. In mod­ern sci­en­tif­ic ter­mi­nol­o­gy, it has been com­plete­ly replaced by the term rhy­o­lite. In fact, both terms describe the same rock — a vol­canic ana­logue of gran­ite with a sim­i­lar min­er­al com­po­si­tion (high con­tent of sil­i­ca, quartz, and feldspars). There­fore, in texts that refer to sources from dif­fer­ent peri­ods.

Liparite (rhy­o­lite) is includ­ed in the list of min­er­als of nation­al impor­tance approved by Res­o­lu­tion of the Cab­i­net of Min­is­ters of Ukraine No. 827 of Decem­ber 12, 1994, as raw mate­r­i­al for glass and porce­lain-faience and raw mate­r­i­al for rub­ble stone.

Physical and mechanical properties of rhyolites

The phys­i­cal and mechan­i­cal prop­er­ties of liparites (rhy­o­lites) deter­mine their prac­ti­cal appli­ca­tion:

• Den­si­ty: Usu­al­ly 2.3–2.6 g/cm³, due to the high sil­i­ca con­tent.
• Strength: In dry con­di­tions, com­pres­sive strength varies between 120–200 MPa, depend­ing on the degree of cemen­ta­tion and the pres­ence of cracks.
• Water absorp­tion: Rhy­o­lite is a porous rock, and this indi­ca­tor can be 0.5–4%, which affects its dura­bil­i­ty in wet con­di­tions.
• Hard­ness: On the Mohs scale, the rock has a hard­ness of about 6–7, mak­ing it suit­able for use as a fac­ing mate­r­i­al.
• Frost resis­tance: Due to their low water absorp­tion and dense struc­ture, rhy­o­lites have high frost resis­tance, which is an impor­tant char­ac­ter­is­tic for build­ing mate­ri­als.
• Struc­tur­al fea­tures: They usu­al­ly have a glassy or por­phyrit­ic struc­ture, often with flu­id stri­a­tions that arise due to the ori­en­ta­tion of crys­tals and glassy com­po­nents in the lava flow.

Genesis and composition

The gen­e­sis of rhy­o­lites is asso­ci­at­ed with high­ly evolved mag­mat­ic sys­tems, where mag­ma is enriched with sil­i­ca and oth­er low-melt­ing com­po­nents. This caus­es high vis­cos­i­ty of the mag­ma, which, when cooled, forms rhy­o­lites. Due to this vis­cos­i­ty, they often form lava domes, lay­ers, or flows, as well as oth­er com­plex vol­canic forms, such as dikes and cov­ers. In mag­mat­ic sys­tems, rhy­o­lites are anal­o­gous to leu­co­crat­ic gran­ites, but are formed on the sur­face or under con­di­tions of shal­low crys­tal­liza­tion.

The main min­er­al com­po­nent of rhy­o­lites is quartz, which often occurs in the form of phe­nocrys­tals. In addi­tion to quartz, the com­po­si­tion includes alka­li feldspars (micro­cline, ortho­clase) and pla­gio­clases. Biotite, amphi­boles, and oth­er min­er­als are often present, but in insignif­i­cant quan­ti­ties. Vol­canic glass is the main com­po­nent of the matrix, espe­cial­ly in rapid­ly solid­i­fied rocks.

Distribution in Ukraine

In Ukraine, liparites (rhy­o­lites) are wide­spread in Zakarpat­tia Oblast, where they form an impor­tant part of the vol­canic com­plex­es of the Vygor­lat-Gutyin­sky range of the Carpathi­ans. They are wide­spread in the south­east­ern sec­tion of the range (the Velykyi Sholes ridge, east of the Borzha­va Riv­er) and in the north­west­ern part (between the Uzh and Lator­i­ca rivers). They are also found in the Bere­hove Hills. These rhy­o­lites have a glassy mas­sive struc­ture, a flu­id band­ed and brec­cia-like tex­ture, and are pre­dom­i­nant­ly dark gray or brown in col­or.

The only explored rhy­o­lite deposit in Ukraine is Ardi­vske, locat­ed in the Bere­hove dis­trict of Zakarpat­tia Oblast, 3 km north­east of the Bere­hove rail­way sta­tion. The geo­log­i­cal struc­ture of the deposit includes Low­er Sar­ma­t­ian vol­canics, which include rhy­o­lites, per­lites, tuffs, lava brec­cias, and tuff brec­cias, which form the vol­canic Mount Adriv. In addi­tion, the struc­ture con­tains Qua­ter­nary deposits (delu­vi­um and elu­vi­um) con­tain­ing rock frag­ments in a loamy mass.

The total reserves of rhy­o­lites at the deposit amount to 20,727 thou­sand tons, of which a sig­nif­i­cant part falls under var­i­ous cat­e­gories of detailed explo­ration (A 2,032 thou­sand tons; B 7,278 thou­sand tons; C₁ 11,417 thou­sand tons). This site is promis­ing for indus­tri­al devel­op­ment due to the large vol­ume of high-qual­i­ty raw mate­ri­als that can be used in the pro­duc­tion of glass and oth­er prod­ucts.

Application of rhyolites

Liparites (rhy­o­lites) have a wide range of uses due to their chem­i­cal and phys­i­cal com­po­si­tion. Due to their high sil­i­ca con­tent, these rocks are ide­al for the glass indus­try, where they are used as the main raw mate­r­i­al for the pro­duc­tion of var­i­ous types of glass, includ­ing con­struc­tion, tech­ni­cal, and dec­o­ra­tive glass.

In addi­tion, liparites can be used in the con­struc­tion indus­try. They are used to pro­duce crushed stone, fac­ing tiles, and ther­mal insu­la­tion mate­ri­als. Their phys­i­cal and mechan­i­cal prop­er­ties, in par­tic­u­lar strength and frost resis­tance, make them suit­able for use in road con­struc­tion and for cre­at­ing durable struc­tures.

Of par­tic­u­lar inter­est is the pos­si­bil­i­ty of using liparites for the pro­duc­tion of refrac­to­ry mate­ri­als and fil­ter media due to their ther­mal sta­bil­i­ty and chem­i­cal inert­ness. These rocks can also be used in agri­cul­ture, for exam­ple, in the pro­duc­tion of soil addi­tives.