ABSTRACT
Results of fission track dating of detrital zircons from the
Scotland sandstones, Barbados, yield a mixture of ages with
several strong groupings from 20-80 Ma, 200-350 Ma, and greater
than 500 Ma. Metamict grains were assumed to fall into the greater
than 500 Ma population.
The youngest population indicates that the Scotland beds,
previously dated by paleontologic methods as Eocene, may actually
be as young as late Oligocene. These ages better constrain the
timing of deposition for these sediments and support the proposal
that the late middle Eocene - early Oligocene Oceanic Fm has
overthrust the Scotland beds. This population (20-80 Ma) may
reflect material derived from the adjacent arc, the
Netherland-Venezuelan Antilles arc, and the Caribbean Mountains of
Venezuela. The 200-350 Ma population may reflect partially
annealed cratonic material, an Andean component, and/or material
associated with a Triassic rifting event. The oldest population
(>500 Ma) and metamict zircons were very likely derived from
the South American craton. 40Ar/39Ar age spectrum analysis of
detrital feldspar from sample 22 provides additional evidence of a
cratonic source for these sediments.
Based on results from this study, distribution of glaucophane, and
paleogeographical constraints it is proposed that the source area
for the Scotland sediments of Barbados was an area of the Guayana
shield which was drained by the Unare (proto-Orinoco?) river
system and deposited in a submarine fan north of the Unare
depression.
Baldwin, S.L., 1984. Fission track dating of detrital zircons
from the Scotland Sandstones, Barbados, West Indies. Unpublished
MSc. thesis, State University of New York at Albany. 97 pp.,
+viii; 1 folded plate (map)
University at Albany Science Library call number: SCIENCE
Oversize (*) QE 40 Z899 1984 B35
thesis (scanned
text) - 6.5MB pdf file
Plate 1 - Geology
of the Scotland area, Barbados, and sample localities
(uncoloured geological map, 1:20,000 scale)
1.5MB pdf file [map position Google Earth kmz
pin; kmz
linked polygon]
Return to MS Theses completed in the
Geological Sciences Program, University at Albany