Order number 940330-160606-96
-001-001
page 37
set 11 with 111 of 111 items
deposition of carbonate from 40 Ma to 20 Ma
Depositional environments show a gradual babinward
progradation of facies with slope carbonates passing
upward into fore-reef,
reef,
back-reef,
and lagoonal
carbonates. Slope strata contain wackestones and
packstones with submarine-cemented lithoclasts, coral,
coralline algae fragments, benthic rotaline forams,
planktonic forams, and echinoderm fragments. Fore-reef
strata are dominantly packstones and boundstones
containing large pieces of coral, abundant benthic
forams, coralline algae fragments, stromatoporoids(?),
and minor planktonic forams. Reef and near-reef
sediments include coralgal boundstones and grainstones
with abundant benthic forams. Halimeda and miliolid
forams are common in lagoonward parts of the back reef.
Sponge borings, geopetal structures, and fractures are
common in reef and fore-reef strata. Lagoonal strata are
wackestones and packstones with common mollusks,
coral,
coralline algae, and benthic forams (rotaline and
miliolid). Diagenesis has extensively altered strata
near the atoll margin. Aragonite dissolution and calcite
cements (radiaxial and cloudy prismatic) are abundant in
fore-reef,
KEYWORDS
EDB
Item
reef,
and some back~-reef strata.
Petrographic
and geochemical data indicate aragonite dissolution and
calcite cementation in seawater at burial depths of 100
to 300 m. Dolomite occurs in slope and deeply buried
reefal carbonates. Most dolomitization occurred at
burial depths of more than 1000 m in cool marine waters
circulating through the atoll. lagoonal strata are not
Significantly altered by marine diagenesis and still
contain abundant primary aragonite and magnesium
calcite.
MARSHALL ISLANDS/reefs ;REEFS/deposition ;ALGAE; CALCITE;
CARBONATE ROCKS; CORALS; DISSOLUTION; FOSSILS; GEOCHEMISTRY;
REEFS;MIOCENE EPOCH; DEPOSITION; STRATIGRAPHY
51
PRIMARY REPORT NUMBER
UCRL--50007-87
ANALYTIC TITLE ENGLISH Summary of the Bikini Atoll ionizing-radiation survey
TITLE ENGLISH
AUTHOR ANALYTIC
PERSONAL AUTHOR
CORPORATE TEXT
PAGE RANGE
PUB. DATE (YYMMDD)
ABSTRACT
Hazards Control Department
annual technology review,
1987
Shingleton, K.L.;Cate, J.L.;Trent, M.G.;Robison,
Griffith, R.V.;Anderson, K.J. (eds.)
~
Lawrence Livermore National Lab.,
1-13
CA
W.L.
(USA)
880700
This survey was designed to measure the beta dose rate
from
{sup
137}Cs and
{sup
90}Sr/{sup
90}Y¥ relative to
previously measured gamma dose rates on Bikini and Eneu
20034871