. The ecology of delta marshes of coastal Louisiana : a community profile. Marsh ecology -- Louisiana; Wetlands -- Louisiana. Figure 15. The position of major delta lobes on the gulf coast during the previous 25,000 years. (A) Late Wisconsin, 25,000 - 20,000 yr B. P. (B) Late Wisconsin, 15,000 yr B. P. (C) Early Holocene, 12,000 - 10,000 yr B. P. (0) Present, 5,000 - 1,000 yr B. P. SL = relative sea level. has sunk beneath the marine waters. Scruton (1960) referred to this stage of the delta cycle as the destructional phase. Thus, in a relatively short period of geologic time both land gain an
. The ecology of delta marshes of coastal Louisiana : a community profile. Marsh ecology -- Louisiana; Wetlands -- Louisiana. Figure 15. The position of major delta lobes on the gulf coast during the previous 25,000 years. (A) Late Wisconsin, 25,000 - 20,000 yr B. P. (B) Late Wisconsin, 15,000 yr B. P. (C) Early Holocene, 12,000 - 10,000 yr B. P. (0) Present, 5,000 - 1,000 yr B. P. SL = relative sea level. has sunk beneath the marine waters. Scruton (1960) referred to this stage of the delta cycle as the destructional phase. Thus, in a relatively short period of geologic time both land gain and land loss occur, a function of the stage of the normal delta cycle. The initial phase of delta progradation is characterized by formation of coastal marshes associated with the advancing delta.^ Coastal marshes deteriorate when a delta lobe is aban- doned, and a new delta cycle begins else- where. Figure 17, a satellite image of the eastern portion of the Mississippi Delta Plain, shows several delta lobes in different stages of construction and destruction. The oldest shown on this image is the St. Bernard Delta, a delta lobe that was actively prograding some 3,000 years before present. This delta lobe remained active for approximately 1,200 years, forming a broad, coastal marshland along the eastern deltaic plain. Approximately 1,800 years ago, the Lafourche channel began its progradation. In the St. Bernard Delta, deprived of its sediment load, marine processes and subsidence (primarily compaction) became dominant. The Lafourche distributary gradually increased its sediment yield and within 1,000 years built out a major delta lobe west of the modern or Balize Delta. During this time the St. Bernard Delta continued to be dominated by marine processes and subsidence. Marine waters began to intrude into the formerly fresh- water marshes, and marshland deterioration 17. Please note that these images are extracted from scanned page images that may have been digitally enhanced fo
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Keywords: ., bookcentury1900, bookcollectionbio, booksubjectwetlandslouisiana
