Recent estuarine deposits, Chesapeake Bay and Apalachicola Bay
Estuarine facies are not easily discernible in the ancient record, because they represent a transition stage between fluvial and marine deposits. Modern estuarine sediments, nevertheless, are widespread because of the ongoing marine transgression. This widespread occurrence indicates that, during a highstand, estuaries are important centers for deposition of sediments shed from the continents. Sedimentologic studies have been made of 2 major estuaries: Chesapeake Bay (the largest US estuary) and Apalachicola Bay (estuary of the largest river in Florida). A detailed sediment budget for the Chesapeake, using radiotracers, clay mineralogy, magnetic stratigraphy, and other methods, demonstrates that the estuary is filling rapidly with sediment. Its remaining sedimentologic lifetime can be measured in centuries. Most of this filling has come at the expense of shoreline erosion. The rate of sedimentation, as measured by C-14, Pb-210, and Cs-137, has accelerated sharply over the past 2 centuries, from a few millimeters per year to present rates of a few centimeters per year. Sediment trapping effectiveness of the Chesapeake is nearly 100%. For Apalachicola Bay, the filling rate has been slower, although it appears to be nearly as efficient in retaining sediment. It has undergone a comparable change in sedimentation rates and sources over the past few centuries, as shown by magnetic stratigraphy and clay mineralogy. Given favorable conditions, such estuaries might be expected to contribute relatively thin but areally extensive bodies of fine-grained sediment to the rock record.
- Research Organization:
- Florida State Univ., Tallahassee
- OSTI ID:
- 5912947
- Report Number(s):
- CONF-850322-
- Journal Information:
- Am. Assoc. Pet. Geol., Bull.; (United States), Vol. 69:2; Conference: American Association of Petroleum Geologists annual meeting, New Orleans, LA, USA, 25 Mar 1985
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ESTUARIES
SEDIMENTATION
CARBON 14
CESIUM 137
CHESAPEAKE BAY
CLAYS
FLORIDA
LEAD 210
MINERALOGY
STRATIGRAPHY
ALKALI METAL ISOTOPES
ALPHA DECAY RADIOISOTOPES
ATLANTIC OCEAN
BAYS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CARBON ISOTOPES
CESIUM ISOTOPES
EVEN-EVEN NUCLEI
FEDERAL REGION IV
GEOLOGY
HEAVY NUCLEI
ISOTOPES
LEAD ISOTOPES
LIGHT NUCLEI
NORTH AMERICA
NUCLEI
ODD-EVEN NUCLEI
RADIOISOTOPES
SEAS
SURFACE WATERS
USA
YEARS LIVING RADIOISOTOPES
020200* - Petroleum- Reserves
Geology
& Exploration