Bulletin of the Geological Society of America . breakdown, carrying the entire orogenetie zone, perhaps leaving the tops ofborder ranges projecting above sealevel as chains of islands (figTire 5).The island chains east of Asia may represent a combination of thesetwo modifications (figure 6). The eastern foreland is covered by thePacific; a typical foredeep borders Japan; the Yellow Sea is ashallow, partly filled foredeep, and the western foreland is partly broken. Figure T.—Blocl-diagirntmi cines samt dem Vorlande vevsenJcten OrofjcnKobers figure 32. page 167. down. Again, both forelands and m
Bulletin of the Geological Society of America . breakdown, carrying the entire orogenetie zone, perhaps leaving the tops ofborder ranges projecting above sealevel as chains of islands (figTire 5).The island chains east of Asia may represent a combination of thesetwo modifications (figure 6). The eastern foreland is covered by thePacific; a typical foredeep borders Japan; the Yellow Sea is ashallow, partly filled foredeep, and the western foreland is partly broken. Figure T.—Blocl-diagirntmi cines samt dem Vorlande vevsenJcten OrofjcnKobers figure 32. page 167. down. Again, both forelands and most of. the orogen may be submergedfigure 7). Perhaps this type is represented by the island chains of XewCaledonia and the Xew Hebrides. The suboceanic ridge extending northand south in the mid-Atlantic may be an orogen of which no portionrises above sealevel. MouxTAix Growth What forces are involved in the building of a two-sided mountainsystem and how do they operate? The motive power for folding andthrusting is probably furnished by contraction of the earth. Compressiondue to contraction is, no doubt, continuous, but in any orogenetie zoneperiods of deformation alternate with periods of quiet, during whichstresses accumulate. But the requirements of gravity must be satisfiedin the crust. Tangential movements, with localization of deformation,tend to build up an excess of material in an orogenetie zone, which thensubsides under the overload. If subsid
Size: 2208px × 1131px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1890, booksubjectgeology, bookyear1890
