Mineralogical and geochemical investigations indicate two general stages of skarnification i.e, prograde and retrograde stages in the Mohammad-Abad district, south west of Yazd province. Metasomatic skarn (Prograde stage) occurred with precipitation of anhydrous calc-silicate mineral assemblages (andradite and diopside- hedenbergite) within the temperature ranges of 470 to 550 ºC. During the retrograde stage (<470 ºC) considerable amounts of anhydrous calc-silicates were altered and replaced by a series of hydrous calc-silicates (epidote, tremolite–actinolite). Finally, both anhydrous and hydrous calc-silicates were altered to fine aggregates of chlorite, calcite, quartz and clay minerals at temperatures lower than 300 ºC. The absence of wollastonite among the calc-silicate assemblages may suggest that andradite and hedenbergite were crystallized from metasomatizing fluids at lower than 550 ºC in the Mohammad-Abad skarn. The presence of intergrowth texture and non-replacive crystal boundaries between garnets and pyroxenes suggest that they were formed   contemporaneously within the temperature and fO₂ ranges of 430–550 ºC and 10^-26–10^-23, respectively. Andradite converted to quartz, calcite and magnetite below 470 ºC and fO₂ = 10^-24–10^-21. Since, both magnetite and pyrite along with quartz and calcite are present in mineral assemblages of sub-stage III, it can be reasoned that the metasomatizing fluids probably had an approximate fS2 10^-6.5 and a temperature of about 430 ºC.

The study area is located at the Soghanchi village (east of Miyandoab city, NW of Iran). The Oligocene age Soghanchi stock is intruded into Permian carbonate rocks during Pyrenean orogenic epoch. Petrographically, the main minerals of this intrusive are plagioclase, biotites, pyroxenes, olivines, hornblendes, and alkali-feldspars. The microscopic and geochemical assessments of intrusive, show gabbro-dioritic, monzo-gabbroic and monzonitic composition with high potassic- calc-alkaline to shoshonitic and meta-aluminous characters. Based on this investigation, the Soghanchi pluton has formed in a continental arc setting. Intrusion of this stock into the Permian limestones, results in different degrees of recrystalization and skarnification. The Soghanchi calcic skarn is mainly composed of anhydrous calc-silicates, retrograde metasomatic products, some calcite, and quartz. Magnetite and minor hematite are the main metallic minerals in this area. Physco-chemical investigations showed 450-650^oC for skarnification (prograde stages) and 400-450^oC for retrograde metasomatic event and iron mineralization.

Siah-Kamar hornfalses and skarns are located about 5Km east of Dehsalm and 85Km west of Nehbandan city, southeast of Birjand Province and east of Lut Block. This Skarn formed by injected Rigi granitoid (Eocene age) into limestone and sandstone (Upper Cratacious).  Rigi Mountain is mainly granodiorite in composition and contains plagioclase, quartz, hornbelend and biotite minerals. Geochemistry and tectonic studies show that this pluton is calc-alkaline and I-type granite. Pyroxene, quartz and plagioclase are main minerals in hornfelses. Investigation of mineralogy and geochemistry Siah-Kamar skarns and hornfalses have indicated that formed during metamorphism and metasomatic stages (prograde and retrograde). Hornfalses and marbles are formed during metamorphism stage and prograde metamorphism stage formed anhydrous calc- silicate minerals assemblages (wollastonite, grossular- andradite and diopside).  During retrograde metasomatism, these minerals have effected by alteration and replacement with hydrous calc- silicate minerals (epidote, chlorite and low termolite-actinolite). Finally during latestaye metasomatism, fine aggregates assemblage minerals such as  of chlorite, quartz and clayminerals are formed. Presence of wollastonite, magnetite and andradite minerals shows that this skarn is formed nearly 550^oC temperature and high oxygen fugacity (fO2=10-12-10-23). Siah- Kamar Skarn has calcic- skarn type.