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The AAPG/Datapages Combined Publications Database
Meander-belt ridges are the most enduring depositional features of the Pleistocene outcrop near Houston, where those on the Beaumont Formation (seaward from Buffalo Bayou) are evident on most early aerial photographs and soils maps, especially the U.S. Geological Survey 1-ft contour-interval topographic sheets of Galveston and Harris Counties, surveyed in 1915-1926. These show the meander-belt ridges as drainage divides between the modern streams, which developed later on the intervening lowlands (except for upper Mustang Bayou). This systematic transposition of the drainage makes it possible to identify the eroded older ridges farther inland as well as those near the Gulf of Mexico.
In the coastal sector from the Brazos River east to Galveston Bay and the San Jacinto River, the meander-belt ridges deflect eastward from successive fluvial terraces along the Brazos Valley and repeatedly branch downslope to the southeast. They belong to four major systems (one of which consists of three subsystems), within each of which the ridge pattern is internally consistent and distinct from contiguous systems. The major systems are separated by the sector's four longer streams, which head just outside the Brazos Valley and flow nearly east: Cypress Creek is the simplest example, and Buffalo Bayou the most complex. These streams flow almost parallel with the nearest meander-belt ridges on their south sides, whereas the ridges from the north approach at much higher angles and ar cut off abruptly by the stream. Each such stream evidently formed along the landward edge of an eastward-prograding increment of coastal plain, where it gathered the blocked drainage off the older plain to the north. As a result, these streams closely follow the unconformable contacts between successive coastal-plain increments, and so mark the approximate landward edges of a succession of distinct unconformity-bounded sequences of strata, each of which is expressed at the surface by its meander-belt ridge system.
Substantially greater ages of the sequences farther inland are indicated by successive increases in the average slope of the ground and amount of erosion and weathering and, for the Beaumont units, by contrasting directional rates of meander-belt slope and quality of channel preservation. However, the boundaries of these formations as shown on the Geologic Atlas of Texas maps are not closely related to the corresponding eastward-flowing streams that fairly well define the stratigraphic sequences. Also, immediately west of the Brazos River and along the San Jacinto River some of the equivalent ridge systems are elongated in the dip direction, which makes the larger regional outcrop pattern much more complex than that described between these rivers.
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