Accretionary lapilli found at Sinan-gun, Jeollanam-do

신안군 선도서 대형 부가화산력 발견…화산 활동 흔적

2020-02-12 10:13 

조근영 기자

중생대 백악기 수중 화산 분출…야구공 모양의 화산재 덩어리

accretionary lapilli at Shinan

Geologists said that accretionary lapilli, a trace of volcanic activity has been found in the mesozoic strata on the north side of Seondo Island, Jido-eup, Sinan-gun, Jeollanam-do.

Accretionary lapilli are ball-like, spherical mass of volcanic ash that forms when a volcano erupts. It is made up of sticky volcanic ash that contains a lot of moisture during volcanic eruptions. The average size is known to be within 10mm.

The volcanic stony particles, including large ones with a diameter of 100 mm or more were found in large quantities 

near Mt. Bumdeok-san, north of Seondo Island. 

<Point of discovery>

This leads to speculation that there has been a massive underwater volcanic eruption in the past.  

The island consists of tuff and volcanic rocks of the Mesozoic Cretaceous Period.

전남 신안군 지도읍 선도 북측 중생대 지층에서 화산 활동 흔적인 부가화산력(첨가화산력, Accretionary Lapilli)이 대량으로 발견됐다. 

부가화산력이란 화산이 분출할 때 형성되는 야구공 형태의 구형에 가까운 화산재 덩어리로 수중에서 화산폭발시 많은 습기를 포함해 끈끈해진 화산재가 뭉쳐서 만들어진다고. 이를 통해 과거 대형의 수중화산폭발이 있었음을 추측하게 한다고.