| Abstract: | Analyses of Sm-Nd and U-Th-Pb systematics, REE, Ba, Sr, Rb and K concentrations were carried out for whole rock and mineral separates from the Nakhla meteorite. The 1.26 ??.07 b.y. Sm-Nd age obtained in this work is in good agreement with those previously obtained by the Rb-Sr and Ar-Ar methods. The high initial ??{lunate}Nd value of +16 suggests that Nakhla was derived from a light REE-depleted, old planetary mantle source. U-Th-Pb data, after correction for pre-analytical terrestrial Pb contamination assuming an age of 1.26 b.y., suggest that the age of the Nakhla source is ???4.33 b.y. The agreement in the age determined by three independent radiometric methods and the high initial ??{lunate}Nd value strongly suggest that the 1.3 b.y. age dates one thorough igneous event in the parent body which not only reset these isotopic systems but also established the chemical and petrologic characteristics observed for the Nakhla meteorite. Using a three-stage Sm-Nd evolution model in combination with LIL element data and estimated partition coefficients, we have tested partial melting and fractional crystallization models to estimate LIL element abundances in a possible Nakhla source. Our model calculations suggest that partial melting of the light REE-depleted source followed by extensive fractional crystallization (???50%) of the partial melt could account for the REE abundances in the Nakhla constituent minerals. The estimated source is depleted in the light REE, Ba, Rb and K and therefore may resemble the MORB source in the earth‘s upper mantle or the upper 60-300 km of the moon. The significantly younger age of Nakhla than the youngest lunar rock; the young differentiation age inferred from the U-Th-Pb data, and the estimated LIL element abundances (including those of K, U and Th) in the source suggest that the Nakhla meteorite may have been derived from a relatively large, well-differentiated planetary body such as Mars. ?? 1982. |
| Genre: | Article |
| ProdID: | 70011676 |
| Citation Author: | Nakamura, N.; Unruh, D. M.; Tatsumoto, M.; Hutchison, R. |
| Citation Contributing Office: | |
| Citation Datum: | |
| Citation Day: | |
| Citation Edition: | |
| Citation Editor: | |
| Citation End Page: | 1573 |
| Citation Issue: | 9 |
| Citation Keywords: | |
| Citation Language: | English |
| Citation Larger Work Title: | Geochimica et Cosmochimica Acta |
| Citation LatN: | |
| Citation LatS: | |
| Citation LonE: | |
| Citation LonW: | |
| Citation Month: | |
| Citation No Pagination: | |
| Citation Number Of Pages: | 19 |
| Citation Online Only Flag: | |
| Citation Phsyical Description: | |
| Citation Projection: | |
| Citation Public Comments: | |
| Citation Publisher: | |
| Citation Series: | |
| Citation Series Code: | |
| Citation Series Number: | |
| Citation Search Results Text: | Origin and evolution of the Nakhla meteorite inferred from the Sm-Nd and U-Pb systematics and REE, Ba, Sr, Rb and K abundances; 1982; Article; Journal; Geochimica et Cosmochimica Acta; Nakamura, N.; Unruh, D. M.; Tatsumoto, M.; Hutchison, R. |
| Citation Start Page: | 1555 |
| Citation Volume: | 46 |
| Citation Year: | 1982 |
| Type: | citation/reference |
| Text: | Origin and evolution of the Nakhla meteorite inferred from the Sm-Nd and U-Pb systematics and REE, Ba, Sr, Rb and K abundances; 1982; Article; Journal; Geochimica et Cosmochimica Acta; Nakamura, N.; Unruh, D. M.; Tatsumoto, M.; Hutchison, R. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Fri, 1 Jan 1982 00:00 -0600 |
| Publisher: | |
