Isopach map showing true stratigraphic thickness of Holocene sediments deposited offshore of Pacifica, California
An isopach map (/ˈaɪsoʊpæk/) illustrates thickness variations within a tabular unit, layer or stratum. Isopachs are contour lines of equal thickness over an area. Isopach maps are utilized in hydrographic survey, stratigraphy, sedimentology, structural geology, petroleum geology and volcanology.
An isopach map is similar to an isochore map, but these terms actually describe different methods of displaying thickness variations within a layer.[1][2]
An isopach map displays lines of equal thickness in a layer where the thicknesses are measured perpendicular to the layer boundaries. Isopach maps are also referred to as True Stratigraphic Thickness (TST) maps.[2][3]
An isochore map displays lines of equal thickness in a layer where the thicknesses are measured vertically. Isochore maps in geology are also referred to as True Vertical Thickness (TVT) maps.[2][3]
Thus, an isochore and isopach map are the same only when both the top and bottom surfaces of the layer shown are horizontal. When the layer shown is inclined, as is usually the case, the thicknesses displayed in an isochore map of the layer will be greater than the thicknesses displayed in an isopach map of the same layer. The terms isopach and isochore are widely confused, and many times maps of True Vertical Thickness (TVT), which by definition are isochore maps, are incorrectly labeled isopach maps.[3]
^Levorsen (1967), p. 596-600 and 616.
^ abcTearpock and Bischke (2002), chap. 14.
^ abcIsopach maps vs isochore maps at www.structuralgeology.org, accessed 5 April 2013.
An isopachmap (/ˈaɪsoʊpæk/) illustrates thickness variations within a tabular unit, layer or stratum. Isopachs are contour lines of equal thickness over...
stratum illustrating the subsurface topographic trends of the strata. Isopachmaps detail the variations in thickness of stratigraphic units. It is not...
Isopachmaps use isopachs (lines of equal thickness) to illustrate variations in thickness of geologic units. In discussing pollution, density maps can...
does cause an increase in seismic amplitude which can be used with an isopachmap to determine net pay. In the mid-1980s the Ekofisk field as a whole and...
Geology, Southern Illinois University Press. Outerbridge, W.F., 2003, Isopachmap and regional correlations of the Fire Clay tonstein, central Appalachian...
Callide Coal Measures, being deposited in a comparatively stable basin. Isopachmaps of the Precipice Sandstone indicate two distinct areas of sediment accumulation...
Retrieved October 19, 2021. Alberta Geological Survey. "Cardium Formation isopachmap with distribution of major Cardium Formation oil and gas fields". Retrieved...
recorded from 1966 to 1970, coupled with well data defined lithofacies and isopachmaps indicating large delta systems. Relative amplitude seismic profiles reveal...
there was a basement high area gently dipping to the north identified by isopachmaps. Thus sediment thickened quickly to the south. To the north strata changed...
Seletuskiri" [Kohtla-Järve. Explanation to the maps] (PDF). Eesti Geoloogiakeskus. Geological base map of Estonia (in Estonian). pp. 11–12. Archived from...
Southwestern Denver Basin, The second report Bedrock Geology, Structure, and IsopachMaps of the Upper Cretaceous to Paleogene Strata between Greeley and Colorado...
even though the reservoir true stratigraphic thickness in that area (or isopach) might be only 10 m, and its true vertical thickness (isochore), 14 m....
locations of sedimentary facies (lithofacies and biofacies) or the mapping of isopachs of equal thickness of sedimentary rock Surficial mapping: recording the...
period of deformation. There are many other anticlines within the basin and isopach data suggests that the formation of these folds occurred mostly during...
Rust, Alison C. (February 6, 2020). "Sources of uncertainty in the Mazama isopachs and the implications for interpreting distal tephra deposits from large...
general trend of pyroclastic dispersal is shown using isopachs (which are analogous to topographic map contours though they illustrate lines of equal thickness...
McKenzie and Santiam Passes region between 4,500 and 1,100 years ago. Isopach mapping of the deposits from Blue Lake Crater suggest an eruptive volume...
assumption that the layers are close to parallel. Convergence map shows lines of equal distance (isopach lines) between key layer and target layer. If the layers...
Global Information