| Title | Carbonation of Cl-rich scapolite boudins in Skallen, East Antarctica; evidence for changing fluid condition in the continental crust |
| Author | Satish-Kumar, M.; Hermann, J.; Tsunogae, T.; Osanai, Y. |
| Author Affil | Satish-Kumar, M., Shizuoka University, Institute of Geosciences, Shizuoka, Japan. Other: Australian National University, Australia; University of Tsukuba, Japan; Kyushu University, Japan |
| Source | Journal of Metamorphic Geology, 24(3), p.241-261, . Publisher: Blackwell, Oxford, United Kingdom. ISSN: 0263- 4929 |
| Publication Date | Apr. 2006 |
| Notes | In English. 78 refs. GeoRef Acc. No: 287539 |
| Index Terms | Antarctica--East Antarctica; Antarctica--Skallen; Antarctica; apatite; Archean; calcite; carbon dioxide; carbonates; chemical composition; chlorine; continental crust; crust; East Antarctica; electron probe data; fine-grained materials; fluid inclusions; fluid phase; fluorapatite; fractures; framework silicates; geologic thermometry; grain size; halogens; ICP mass spectra; inclusions; infiltration; Lutzow- Holm Complex; mass spectra; metals; metamorphic rocks; microthermometry; Napier Complex; phosphates; poikilitic texture; Precambrian; Raman spectra; rare earths; recrystallization; scapolite; scapolite group; silicates; Skallen Antarctica; spectra; textures; zoning |
| Abstract | Spectacular reaction textures in poikiloblastic scapolitite boudins, within marbles in the continental crust exposed in the Ltzow-Holm Complex, East Antarctica, provide insights into the changing fluid composition and movement of fluid along grain boundaries and fractures. Petrographic and geochemical features indicate scapolite formation under contrasting fluid compositions. Core composition of scapolite poikiloblasts (ScpI) are marialitic (Cl = 0.7 apfu) whereas rims in contact with biotite or clinopyroxene are meionite rich. Fine-grained recrystallized equigranular scapolite (ScpII) shows prominent chemical zoning, with a marialitic core and a meionitic rim (Cl = 0.36 apfu). Scapolite poikiloblasts are traversed by ScpIII reaction zones along fractures with compositional gradients. Pure CO2 fluid inclusions are observed in healed fractures in scapolite poikiloblasts. These negative crystal-shaped fluid inclusions are moderately dense, and are believed to be coeval with ScpIII formation at temperatures #gt600 °C and a minimum pressure of c. 3.8 kbar. Grain-scale LA-ICPMS studies on trace and rare earth elements on different textural types of scaplolites and a traverse through scapolite reaction zone with compositional gradient suggest a multistage fluid evolution history. (MOD. JOURN. ABST.) |
| URL | http://hdl.handle.net/10.1111/j.1525-1314.2006.00635.x |
| Publication Type | journal article |
| Record ID | 84745 |