Tholeiitic and alkalic basalts of the oldest Pacific Ocean crust
Links
- More information: Publisher Index Page (via DOI)
- Download citation as: RIS | Dublin Core
Abstract
Approximately 160 Ma old basaltic lavas obtained from ODP Site 801 in the Pigafetta Basin represent the first Jurassic oceanic crust recovered in the Pacific Ocean and the oldest in situ oceanic crust discovered anywhere. The basement consists of an upper alkali olivine basalt sequence and a lower tholeiitic sequence separated by a yellow Fe-rich hydrothermal sedimentary deposit. The aphyric and sparsely plagiodase-olivine±spinel phyric tholeiites exhibit depleted, open–system fractionated characteristics with trace element abundances and Pb–Nd isotopic compositions similar to normal mid-ocean ridge basalts (N-MORB). The aphyric alkali basalts, although showing some overlap in isotopic composition with MORB, exhibit strong similarities in terms of incompatible element abundances to ocean island basalts (OIB). They could represent either OIB-type off-axis volcanism or an alkalic event possibly associated with the waning stages of spreading axis volcanism in the Pigafetta Basin. All lavas have undergone low-grade anoxic smectite–carbonate alteration, although flows underlying the Fe-rich sediments have suffered hydrothermal alteration and fracturing.
Study Area
| Publication type | Article |
|---|---|
| Publication Subtype | Journal Article |
| Title | Tholeiitic and alkalic basalts of the oldest Pacific Ocean crust |
| Series title | Terra Nova |
| DOI | 10.1111/j.1365-3121.1991.tb00143.x |
| Volume | 3 |
| Issue | 3 |
| Year Published | 1991 |
| Language | English |
| Publisher | Wiley |
| Description | 8 p. |
| First page | 257 |
| Last page | 264 |
| Other Geospatial | Pacific Ocean |
| Google Analytic Metrics | Metrics page |