Neogene biogenic sediments of onshore Peru: part I, sedimentology and stratigraphy
Conference
·
· Geol. Soc. Am., Abstr. Programs; (United States)
OSTI ID:6462740
The Sechura (approx.6/sup 0/S) and Pisco (approx.14/sup 0/S) Basins of onshore Peru contain Miocene diatom and phosphate rich sediments which sharply contrast with underlying clastics. In the Sechura Basin the Miocene clastic Mancora, Heath and Montera Formations are overlain by the Zapallal Formation which grades upwards from a weakly biogenic base into fairly pure diatomites (biogenic silica >20%) and ore grade phosphorite (P/sub 2/O/sub 5/>20%). Biogeneic content decreases in the eastern basin as clastic content increases. The base of the Zapallal Formation has been dated at between 12.2 and 14.0 mybp using radiolaria correlated to magnetic stratigraphy by Theyer, et al (1978), and the phosphatic section yields dates of between 8.0 and 11.2 my. In the Pisco Basin the Eocene clastic Paracas Formation is overlain unconformably by the Miocene Pisco Formation which contains a basal sequence of cross-bedded clastics, tuffs, and partially recrystallized diatomites; a phosphorite bearing middle sequence; and a diatom rich top. Current direction from the cross beds of the basal Pisco Formation indicate a generally southerly transport direction but with considerable directional variability. This may be related to the Peru under-current which shows highly variable strength and direction near 15/sup 0/S.
- Research Organization:
- Rice Univ., Houston, TX (USA)
- OSTI ID:
- 6462740
- Report Number(s):
- CONF-8510489-
- Conference Information:
- Journal Name: Geol. Soc. Am., Abstr. Programs; (United States) Journal Volume: 17
- Country of Publication:
- United States
- Language:
- English
Similar Records
Neogene biogenic sediments of onshore Peru. Part 2. Geochemistry and diagenesis
Mixing of biogenic siliceous and terrigenous clastic sediments: South Belridge field and Beta field, California
Late Eocene diatomite from the Peruvian coastal desert, coastal upwelling in the eastern Pacific, and Pacific circulation before the terminal Eocene event
Conference
·
Mon Dec 31 23:00:00 EST 1984
· Geol. Soc. Am., Abstr. Programs; (United States)
·
OSTI ID:6576272
Mixing of biogenic siliceous and terrigenous clastic sediments: South Belridge field and Beta field, California
Conference
·
Tue May 01 00:00:00 EDT 1990
· AAPG Bulletin (American Association of Petroleum Geologists); (USA)
·
OSTI ID:6634883
Late Eocene diatomite from the Peruvian coastal desert, coastal upwelling in the eastern Pacific, and Pacific circulation before the terminal Eocene event
Journal Article
·
Thu Sep 01 00:00:00 EDT 1988
· Geology; (United States)
·
OSTI ID:6860857
Related Subjects
58 GEOSCIENCES
580100* -- Geology & Hydrology-- (-1989)
580300 -- Mineralogy
Petrology
& Rock Mechanics-- (-1989)
ALGAE
CENOZOIC ERA
CHROMOPHYCOTA
DEVELOPING COUNTRIES
DIATOMS
GEOLOGIC AGES
GEOLOGIC FORMATIONS
GEOLOGIC STRUCTURES
GEOLOGY
LATIN AMERICA
PALEONTOLOGY
PERU
PETROLOGY
PLANTS
SEDIMENTARY BASINS
SEDIMENTS
SOUTH AMERICA
STRATIGRAPHY
TERTIARY PERIOD
580100* -- Geology & Hydrology-- (-1989)
580300 -- Mineralogy
Petrology
& Rock Mechanics-- (-1989)
ALGAE
CENOZOIC ERA
CHROMOPHYCOTA
DEVELOPING COUNTRIES
DIATOMS
GEOLOGIC AGES
GEOLOGIC FORMATIONS
GEOLOGIC STRUCTURES
GEOLOGY
LATIN AMERICA
PALEONTOLOGY
PERU
PETROLOGY
PLANTS
SEDIMENTARY BASINS
SEDIMENTS
SOUTH AMERICA
STRATIGRAPHY
TERTIARY PERIOD