thumbnail

Radiogenic strontium-87 as an index of geologic processes

Science

By:
,

Links

  • The Publications Warehouse does not have links to digital versions of this publication at this time

Abstract

The abundance of radiogenic Sr87 relative to Sr86 at the time of crystallization has been determined for 45 rocks. The total range in the ratio Sr87/Sr86 is less than 2 percent. Ratios for recent lavas range from 0.702 to 0.711. Oceanic basalts are closely grouped at 0.703, whereas ratios for continental volcanic rocks spread from 0.702 to 0.711. Among the volcanic rocks, ranging from basalt to rhyolite, no correlation was found between original ratio and rock type. Older mafic and felsic rocks that include both plutonic and extrusive types also cover this same range in original Sr87/Sr86 ratios; however, there is a definite trend with geologic time. Pre-cambrian rocks give values as low as 0.700. The data indicate that Sr87/Sr86 of the weathering crust has changed 1.1 percent in 3000 million years, while the ratio in the mantle has changed no more than 0.5 percent.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Radiogenic strontium-87 as an index of geologic processes
Series title:
Science
Volume
140
Issue:
3572
Year Published:
1963
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
First page:
1214
Last page:
1217
Number of Pages:
4