USGS - Pontchartrain Geochemistry

Environmental Geochemistry and Sediment Quality in Lake Pontchartrain

Summary Table of Figures for Lake Pontchartrain Geologic History

Field studies and background data	Fig. 1	Location map for field surveys
Field studies and background data	Fig. 2	Bathymetric and sediment texture
Subsurface expressions of the ancestral Mississippi River	Fig. 3	(a) Seismic profile (b) Channel overlain by estuarine fill
Pleistocene-Holocene sediment distributions	Fig. 4	Contour map of depth to Pleistocene surface
	Fig. 5	Generalized vibracore with typical sediment units
	Fig. 6	USACE boring and seismic profiles
	Fig. 7	High-resolution seismic profile with vibracore
	Fig. 8	Thinning of Holocene deposits in northern Lake Pontchartrain
Schematic development of Lake Pontchartrain	Fig. 9	Changes over time with sea-level rise
Sediment profiles from NW Lake Pontchartrain to Lake Borgne	Fig. 10	Superposition of various depositional units (marsh, estuarine/lagoonal, deltaic, etc.)
Schematic development of the Northern Gulf of Mexico shelf	Fig. 11	Estuary and shelf development through Holocene transgression