"Ampato (possibly from Quechua hamp'atu[1] or from Aymara jamp'atu[2], both meaning "frog") is a dormant 6,288-metre (20,630 ft) stratovolcano in the Andes of southern Peru, about 70–75 kilometres (43–47 mi) northwest of Arequipa." - maybe spread out some of this into two sentences? It's just a lot to digest in the first sentence
"Holocene ash layers in surrounding peat bogs may testify the occurrence of recent eruptions." - missing "to" after "testify"
"the city of Arequipa lies 70–75 kilometres (43–47 mi) southeast of Ampato.[4]" - instead of repeating the volcano name, maybe just "kilometres... to the southeast"
"some of which have had eruptions in historical time including El Misti, Huaynaputina, Sabancaya and Ubinas." - instead of "have had eruptions", why not "erupted in historical time"
"The edifice is incised by glacial valleys.[10]" - comes abruptly, perhaps move within the section to the last paragraph?
"after the opening of the southern Atlantic Ocean.[8]" - what does opening mean here? why is that important?
"The present day volcanic arc resulted from a narrowing of the Barroso group.[12]" - again, what is the importance of the narrowing? needs more explanation
"but appears to be about on average 0.08–0.09 cubic kilometres per millennium (0.019–0.022 cu mi/ka) but without considering "spurt"-like behaviour; volcano growth in fits and spurts has been observed at many other volcanic arc volcanoes.[16]" - repetition of "but" dilutes the meaning/intent of this sentence
"The southern cone developed in several different stages; a first lavic stage generated lava flows emanating from the summit;[20" - what's a lavic stage? explain
" a first lavic stage generated lava flows emanating from the summit;[20] dating of two lava flows has produced ages of 34,000 ± 8,000 and 40,000 ± 3,000 years before present. More than 20 metres (66 ft) of block-and-ash flows was erupted onto the eastern and western flanks of Ampato,[21] and the block-and-ash flows consist of one andesitic and one dacitic formation; both appear to relate to a lava dome forming stage of volcanic activity. These block-and-ash flows are themselves covered on both the eastern and the western flanks by more thick lava flows, which make up a 150–200 metres (490–660 ft) thick unit and again consist of one andesitic and one dacitic unit; both units appear to have been erupted during the last glacial maximum.[22]" - lots of lava flows and block and ash flows in close vicinity; try finding synonyms or rewording?
"Early Holocene (11,000 - 8,000 years before present) ash layers" - if you're going to explain what Holocene refers to, do it at the first mention, not here
"Ampato (possibly from Quechua hamp'atu[1] or from Aymara jamp'atu[2], both meaning "frog") is a dormant 6,288-metre (20,630 ft) stratovolcano in the Andes of southern Peru, about 70–75 kilometres (43–47 mi) northwest of Arequipa." - maybe spread out some of this into two sentences? It's just a lot to digest in the first sentence
"Holocene ash layers in surrounding peat bogs may testify the occurrence of recent eruptions." - missing "to" after "testify"
"the city of Arequipa lies 70–75 kilometres (43–47 mi) southeast of Ampato.[4]" - instead of repeating the volcano name, maybe just "kilometres... to the southeast"
"some of which have had eruptions in historical time including El Misti, Huaynaputina, Sabancaya and Ubinas." - instead of "have had eruptions", why not "erupted in historical time"
"The edifice is incised by glacial valleys.[10]" - comes abruptly, perhaps move within the section to the last paragraph?
"after the opening of the southern Atlantic Ocean.[8]" - what does opening mean here? why is that important?
"The present day volcanic arc resulted from a narrowing of the Barroso group.[12]" - again, what is the importance of the narrowing? needs more explanation
"but appears to be about on average 0.08–0.09 cubic kilometres per millennium (0.019–0.022 cu mi/ka) but without considering "spurt"-like behaviour; volcano growth in fits and spurts has been observed at many other volcanic arc volcanoes.[16]" - repetition of "but" dilutes the meaning/intent of this sentence
"The southern cone developed in several different stages; a first lavic stage generated lava flows emanating from the summit;[20" - what's a lavic stage? explain
" a first lavic stage generated lava flows emanating from the summit;[20] dating of two lava flows has produced ages of 34,000 ± 8,000 and 40,000 ± 3,000 years before present. More than 20 metres (66 ft) of block-and-ash flows was erupted onto the eastern and western flanks of Ampato,[21] and the block-and-ash flows consist of one andesitic and one dacitic formation; both appear to relate to a lava dome forming stage of volcanic activity. These block-and-ash flows are themselves covered on both the eastern and the western flanks by more thick lava flows, which make up a 150–200 metres (490–660 ft) thick unit and again consist of one andesitic and one dacitic unit; both units appear to have been erupted during the last glacial maximum.[22]" - lots of lava flows and block and ash flows in close vicinity; try finding synonyms or rewording?
"Early Holocene (11,000 - 8,000 years before present) ash layers" - if you're going to explain what Holocene refers to, do it at the first mention, not here