Cretaceous and Tertiary samples dredged from Florida Escarpment, Eastern Gulf of Mexico

Conference · Thu Sep 01 04:00:00 EDT 1983 · Am. Assoc. Pet. Geol., Bull.; (United States)

OSTI ID:6797208

Freeman-Lynde, R P

Cretaceous and Tertiary rocks were dredged along the Florida Escarpment at five areas south of 27/sup 0/05'N in late 1982 during cruise LY-82A of USNS Lynch. The escarpment was sampled from near the base (as deep as 3300 m, 10,800 ft) to near the top (as shallow as 1500 m, 4900 ft) of the slope. Presumed middle Cretaceous dolomites deposited in hypersaline bank-interior environments were taken primarily from the walls of canyons incised from 10 to 50 km (6 to 30 mi) into the escarpment, and also from the escarpment proper at several dredge stations. Limestone lithologic characteristics are generally bioturbated miliolid and mollusk wackestone/packstone (lagoonal) and fenestral and algal-laminated mudstone/wackestone (peritidal). Some dolomites retain primary sedimentary structures (e.g., mottling and algal lamination), whereas others appear structureless, perhaps due to recrystallization. Few of the middle Cretaceous samples were deposited under high-energy conditions. Those that are high-energy deposits are bioclastic rudstones and coral boundstones. Late Cretaceous and Tertiary deep-water limestones and chalks unconformably overlie and drape the older shallow-water carbonates. The limestones are Late Cretaceous through Pleistocene. The limited occurrence of high-energy facies rocks indicates that the escarpment has been eroded bankward over its entire length south of 27/sup 0/05'N, and not just at canyon reentrants. The younger deep-water rocks reflect the drowning of the middle Cretaceous platform in Late Cretaceous time. The facies change from limestone to dolomite is attributed to higher salinities in the bank interior during the middle Cretaceous.

• Research Organization: Naval Ocean Research and Development Activity, NSTL Station, MS
• OSTI ID: 6797208
• Report Number(s): CONF-8310301-
• Conference Information: Journal Name: Am. Assoc. Pet. Geol., Bull.; (United States) Journal Volume: 67:9
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580300* -- Mineralogy
Petrology
& Rock Mechanics-- (-1989)
ATLANTIC OCEAN
CARBONATE ROCKS
CARIBBEAN SEA
CENOZOIC ERA
CRETACEOUS PERIOD
DREDGING
FEDERAL REGION IV
FLORIDA
GEOLOGIC AGES
GEOLOGIC HISTORY
GULF COAST
GULF OF MEXICO
LITHOLOGY
MESOZOIC ERA
NORTH AMERICA
ROCKS
SEAS
SEDIMENTARY ROCKS
SURFACE WATERS
TERTIARY PERIOD
USA