| [[File:M91FG192.JPG|thumb|300px|{{figure number|7}}Generalized map and cross sections showing major environments and facies associations of a barrier island-lagoonal system (from McCubbin<ref name=McCubbin />). Reprinted with permission from the AAPG.]] | | [[File:M91FG192.JPG|thumb|300px|{{figure number|7}}Generalized map and cross sections showing major environments and facies associations of a barrier island-lagoonal system (from McCubbin<ref name=McCubbin />). Reprinted with permission from the AAPG.]] |
− | Barrier islands form thick, well-sorted sand bodies with a tabular geometry ([[:File:M91FG192.JPG|Figure 7]]). They typically comprise a composite of beach, dune, and upper shoreface sandstones (Galloway, 1986). Barrier islands can be continuous for tens of kilometers along strike but may only be a few kilometers wide. Local heterogeneity can be provided by tidal channel inlet deposits. These form crosscutting lenticular pods, disrupting the layer-cake continuity of the barrier island body. Recent barrier island sediments on the South Carolina coast provide a modern analog and are described in detail by Sexton and Hayes (1996). | + | Barrier islands form thick, well-sorted sand bodies with a tabular geometry ([[:File:M91FG192.JPG|Figure 7]]). They typically comprise a composite of beach, dune, and upper shoreface sandstones.<ref name=Galloway1986>Galloway, W. E., 1986, [http://archives.datapages.com/data/bulletns/1986-87/data/pg/0070/0007/0750/0787.htm Reservoir facies architecture of microtidal barrier systems]: AAPG Bulletin, v. 70, no. 7, p. 787–808.</ref> Barrier islands can be continuous for tens of kilometers along strike but may only be a few kilometers wide. Local heterogeneity can be provided by tidal channel inlet deposits. These form crosscutting lenticular pods, disrupting the layer-cake continuity of the barrier island body. Recent barrier island sediments on the South Carolina coast provide a modern analog and are described in detail by Sexton and Hayes (1996). |
| Ambrose et al. (1997) gave an example from an oil field in Venezuela where sweep has resulted from preferential water encroachment along the sandstone-rich core of the barrier island depositional axis with bypassed oil remaining along the landward pinch-out edge. | | Ambrose et al. (1997) gave an example from an oil field in Venezuela where sweep has resulted from preferential water encroachment along the sandstone-rich core of the barrier island depositional axis with bypassed oil remaining along the landward pinch-out edge. |