Identifications using Quartz Inclusions in Sand and Soil

2023 Fiscal Year Final Research Report

• Project/Area Number: 20K01153
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 04010:Geography-related
• Research Institution: Japan Coast Guard Academy Center for Maritime Safety and Security Studies
• Principal Investigator: Noriko Kawamura 海上保安大学校(海上保安国際研究センター), 海上保安国際研究センター, 准教授 (80442458)
• Project Period (FY): 2020-04-01 – 2024-03-31
• Keywords: 法地質学 / 包有物 / 磁気測定 / 非破壊分析

Outline of Final Research Achievements

Sediment and soil samples are consisted of rock fragments and minerals, and are collected as the evidence in criminal investigations. We are asked “where the rock fragments and minerals come from?” in forensic science and geology. We focused to beach where illegal activities and transportations of sediment particles have been occurred. Itamiya et al. (2019) reported results of surface microtexture of quartz in the beach sediment samples at nine sites from Aomori Prefecture in Japan, and revealed the relationship between the quartz morphological features per sites. We focused on not only quartz, but also feldspar and magnetic minerals at the same sites. The beach sediments are affected under pH condition change, either seawater (alkaline) or rainfall (acidic), while the inclusions are less susceptible to the change. We analysed the inclusions, and revealed that inclusions in quartz, feldspar, and magnetic minerals can be magnetically identified.

Free Research Field

法地質学

Academic Significance and Societal Importance of the Research Achievements

研究開始当初は、石英の包有物のみに着目していたが、堆積物に普遍的に含まれる磁性鉱物長石の包有物についても磁気分析や元素分析を行ったところ、採取地点ごとの特徴を見出すことができた。石英に限らず、他の鉱物の包有物の特徴を組み合わせることにより、より詳細な堆積粒子の採取地点の推定に応用できる可能性がある。このことは、法科学分野での堆積粒子の由来推定だけでなく、環境学分野や地質学分野での粒子の移動経路についての研究において、大きな発展が見込める。