Characteristics and Genesis of Terrace Soils in Yeongnam Area -IV: Soil micromorphological features

영남지역(嶺南地域)에 분포(分布)된 단구지토양(段丘地土壤)의 특성(特性)과 생성연구(生成硏究) -제(第) 4 보(報) : 토양미세형태학적(土壤微細形態學的) 특성(特性)

A soil micromorphological study of clayey terrace soils in Yeongnam area was carried out to investigate the soil genetic features and to distinguish the soil parent materials. Dominant plasmic fabrics in the terrace soils were vosepic, mosepic, insepic, and masepic of sepic fabrics but the Geugrag and Upyeong in Yeongil sequence have an asepic fabrics. Embedded grain cutans in the terrace soils were characterized by having porphyroskelic related distribution. Among pedological features of the B horizons of the terrace soils, the argillic cutans of ferriargillans and glaebules of manganiferrous concretions were the dominant in mineralogical composition, and the papules are abundant in the most terrace soils indicating that the soils are generally old. The substrata of the Bancheon in Yeongcheon and Upyeong in Yeongil area were so different from the terrace deposits in plasmic fabrics that these soils were believed to be composed of bisequum profiles. Because of having the free grain cutans, it was considered that the substrata of Bancheon in Yeongcheon and Upyeong in Yeongil area might have a period of soil formation before deposition of the terrace materials.

영남지역(嶺南地域)에 분포(分布)된 단구지토양(段丘地土壤)의 미세형태각적(微細形態覺的) 특징(特徵)을 토양생성(土壤生成)과 모재층구분(母材層區分)을 중심(中心)으로 실시(實施)한 결과(結果) ; 1. 단구토양(段丘土壤)의 원질배열(原質配列)은 Porphyroskelic 상(狀)이고 토양조직(土壤組織)(Soil fabric)은 Vosepic, Mosepic, Insepic, Masepic 등(等)이 대부분(大部分)이었으나 영일지역(迎日地域)의 극락통(極樂統)과 우평통(牛坪統)에서는 Asepic fabric도 있었다. 2. 단구토양(段丘土壤)의 B층(層)에는 ferriargillans, manganiferrous concretions과 papules 등(等)의 토양생성학적(土壤生成學的) 특징(特徵)이 현저(顯著)하게 발달(發達)된 Argillic B층(層)이 있었다. 3. 모재(母材)의 불연속성(不連續性)이 예상(豫想)되는 영천(永川)의 반천통(盤泉統)과 영일(迎日)의 우평통(牛坪統) 기층(基層)은 Plasmic fabric이 단구퇴적물(段丘堆積物)과 판이(判異)하였으므로 bisequum profile로 되어 있음을 알 수 있었으며 이들 토층(土層)에도 유리입자상(遊離粒子狀) 점토피막(粘土皮膜)(Free grain cutans)이 생성(生成)되어 있는 것으로 보아 단구퇴적물(段丘堆積物)의 퇴적전(堆積前)에 일정기간(一定期間) 동안 토양생성작용(土壤生成作用)을 받을 기회가 있었던 것으로 추측(推測)되었다.