2011 Fiscal Year Final Research Report
Longevity of fracture in crystalline rocks by using Rb-Sr dating method
| Project/Area Number |
22656204
|
|---|
| Research Category |
Grant-in-Aid for Challenging Exploratory Research
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
Earth system and resources enginnering
|
|---|
| Research Institution | Nagoya University |
|---|
Principal Investigator |
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
YAMAMOTO Koshi 名古屋大学, 大学院・環境学研究科, 教授 (70183689)
ASAHARA Yoshihiro 名古屋大学, 大学院・環境学研究科, 助教 (10281065)
|
|---|
| Project Period (FY) |
2010 – 2011
|
| Keywords | 応用地質 |
|---|
| Research Abstract |
In this research, formation process and the age of formation of fracture in granitic rocks has been focused. The result shows that different plutons have identical episodes of fracturing and fracture filling, consisting of : brittle tensile fracturing, due to decreasing temperature through the ductile-brittle transition after plutonic intrusion(Stage I); relatively rapid uplifting accompanied by hydrothermal water circulation which produced un-crushed layered mineral fillings(Stage II); and a period of low-temperature meteoric water circulation following exposure after uplift(Stage III). The parageneses of carbonate mineral fracture fillings and their carbon isotopic compositions(^<14C>,δ^<13> C) show that there were distinct episodes of carbonate mineral precipitation during the rapid uplifting of a pluton. The carbonate minerals that formed during each episode incorporated carbon from a distinct source. The evolution of fillings identified here enable development of a specific model of fracturing and persistence of fluid conducting systems in the plutons of the orogenic field.
|
