| Title | Mantle heterogeneity beneath the Antarctic-Phoenix Ridge off Antarctic Peninsula |
| Author | Choi, S.; Choe, W.; Lee, J. |
| Author Affil | Choi, S., Korea Polar Research Institute, Incheon, South Korea |
| Source | Island Arc, 17(1), p.172-182, . Publisher: Blackwell Scientific, Carlton, Victoria, Australia. ISSN: 1038- 4871 |
| Publication Date | Mar. 2008 |
| Notes | In English. 47 refs. GeoRef Acc. No: 285598 |
| Index Terms | Antarctica--Antarctic Peninsula; Drake Passage; Southern Ocean; alkaline earth metals; Antarctic Peninsula; Antarctic- Phoenix Ridge; Antarctica; basalts; Cenozoic; depth; enriched-type melts; enrichment; fracture zones; Hero fracture zone; heterogeneity; igneous rocks; isotope ratios; isotopes; lead; magma contamination; major elements; mantle; melts; metals; mid-ocean ridge basalts; mid-ocean ridges; Miocene; Nd- 144/Nd-143; neodymium; Neogene; normal-type melts; ocean floors; partial melting; Pb- 206/Pb-204; Pb-207/Pb-204; Pb-208/Pb-204; Phoenix Plate; plate tectonics; Pliocene; radioactive isotopes; rare earths; samarium; sea-floor spreading; Sm-147/Nd-144; spreading centers; Sr-87/Sr-86; stable isotopes; strontium; Tertiary; trace elements; volcanic rocks |
| Abstract | We determined the Sr, Nd and Pb isotopic compositions of basalts recovered from the Antarctic-Phoenix Ridge (APR), a fossil spreading center in the Drake Passage, Antarctic Ocean, in order to understand the nature of the subridge mantle source. There are no known hotspots in close proximity to the site. We observe that small-scale isotopic heterogeneity exists at a shallow level in the subaxial mantle of the APR. Enriched (E-type) mid-ocean ridge basalts (MORB) coexist with normal (N-type) MORB in this region. The E-type basalts are: (i) relatively young compared to the N-type samples; (ii) were erupted after the extinction of the APR; and (iii) have been generated by low-degree partial melting of an enriched mantle source. Extinction of the APR likely caused the extent of partial melting in this region to decrease. We interpret that the geochemically enriched materials dispersed in the ambient depleted mantle were the first fraction to melt to form the E-type MORB. |
| URL | http://hdl.handle.net/10.1111/j.1440-1738.2007.00609.x |
| Publication Type | journal article |
| Record ID | 84512 |