N. Nakamura M. Tatsumoto D.M. Unruh 1977 <div id="abstracts" class="Abstracts u-font-serif text-s"><div id="ab1" class="abstract author" lang="en"><div id="aep-abstract-sec-id4"><p>The Rb<img src="https://sdfestaticassets-us-east-1.sciencedirectassets.com/shared-assets/55/entities/sbnd.gif" alt="single bond" data-mce-src="https://sdfestaticassets-us-east-1.sciencedirectassets.com/shared-assets/55/entities/sbnd.gif">Sr, Sm<img src="https://sdfestaticassets-us-east-1.sciencedirectassets.com/shared-assets/55/entities/sbnd.gif" alt="single bond" data-mce-src="https://sdfestaticassets-us-east-1.sciencedirectassets.com/shared-assets/55/entities/sbnd.gif">Nd, and U<img src="https://sdfestaticassets-us-east-1.sciencedirectassets.com/shared-assets/55/entities/sbnd.gif" alt="single bond" data-mce-src="https://sdfestaticassets-us-east-1.sciencedirectassets.com/shared-assets/55/entities/sbnd.gif">Pb systematics of the eucrite Pasamonte have been studied in order to investigate the relative susceptibility of the different systems to post-crystallization events and to determine the age and history of the meteorite. The Rb<img src="https://sdfestaticassets-us-east-1.sciencedirectassets.com/shared-assets/55/entities/sbnd.gif" alt="single bond" data-mce-src="https://sdfestaticassets-us-east-1.sciencedirectassets.com/shared-assets/55/entities/sbnd.gif">Sr and²³⁸U-²⁰⁶Pb data of mineral separates do not define an isochron but the Sm<img src="https://sdfestaticassets-us-east-1.sciencedirectassets.com/shared-assets/55/entities/sbnd.gif" alt="single bond" data-mce-src="https://sdfestaticassets-us-east-1.sciencedirectassets.com/shared-assets/55/entities/sbnd.gif">Nd data define an internal isochron which corresponds to the formation age of<i>4.58 ± 0.12b.y.</i><span>&nbsp;</span>(10⁹<span>&nbsp;</span>years). The²⁰⁷Pb-²⁰⁶Pb data of mineral separates define an apparent age of<i>4.53 ± 0.03b.y.</i>, however we conclude that this age, while in agreement with the Sm<img src="https://sdfestaticassets-us-east-1.sciencedirectassets.com/shared-assets/55/entities/sbnd.gif" alt="single bond" data-mce-src="https://sdfestaticassets-us-east-1.sciencedirectassets.com/shared-assets/55/entities/sbnd.gif">Nd age, is not strictly valid since the U<img src="https://sdfestaticassets-us-east-1.sciencedirectassets.com/shared-assets/55/entities/sbnd.gif" alt="single bond" data-mce-src="https://sdfestaticassets-us-east-1.sciencedirectassets.com/shared-assets/55/entities/sbnd.gif">Pb data indicate at least three stages of evolution. The U<img src="https://sdfestaticassets-us-east-1.sciencedirectassets.com/shared-assets/55/entities/sbnd.gif" alt="single bond" data-mce-src="https://sdfestaticassets-us-east-1.sciencedirectassets.com/shared-assets/55/entities/sbnd.gif">Pb data indicate that the parent body of the meteorite experienced brecciation shortly after the formation of the parent body surface (<i>∼4.2–4.45b.y.</i><span>&nbsp;</span>ago) and a recent disturbance (collision?)<i>6 ± 30m.y.</i><span>&nbsp;</span>ago. The latter age is within the range of cosmic ray exposure ages for achondrites.</p></div></div></div><ul id="issue-navigation" class="issue-navigation u-margin-s-bottom u-bg-grey1"></ul> application/pdf 10.1016/0012-821X(77)90141-8 en Elsevier History of the Pasamonte achondrite: Relative susceptibility of the SmNd, RbSr, and UPb systems to metamorphic events article