. Shore processes and shoreline development . known occurrence of fault-lines incertain fjords, and of the rectangular pattern of other fjords,which suggests an intersecting fault pattern. There can belittle doubt but that crushed zones along faults, and infaultedstrips of weak rook, have often determined the position andpattern of fjord-valleys. It is, however, an error of reasoningto jump to the conclusion that faults make fjords. As alreadynoted, the glacial theory of fjord origin fully recognizes the factthat the pre-glacial valleys later transformed into fjords wereoften excavated along a
. Shore processes and shoreline development . known occurrence of fault-lines incertain fjords, and of the rectangular pattern of other fjords,which suggests an intersecting fault pattern. There can belittle doubt but that crushed zones along faults, and infaultedstrips of weak rook, have often determined the position andpattern of fjord-valleys. It is, however, an error of reasoningto jump to the conclusion that faults make fjords. As alreadynoted, the glacial theory of fjord origin fully recognizes the factthat the pre-glacial valleys later transformed into fjords wereoften excavated along ancient fault-lines. Stream erosion natu-ally took advantage of the weak belts determined by faulting,forming fault-line valleys; but not until ice occupied these pre-glacial stream valleys and profoundly changed their shape andtheir depth, were the forms which we called fjords prove the presence of a fault-line through a fjord is, therefore,to prove nothing as to the tectonic origin of the fjord. The SHORELINES OF SUBMERGENCE 185. 186 TERMINOLOGY AND CLASSIFICATION OF SHORES tectonic theory, moreover, affords no rational explanation of therestriction of fjords to high latitudes, nor of the identity in formbetween fjord valleys and unsubmerged glacial troughs, betweenfjord-basins and trough lake-basins. In the glacial theory alonedo all of the phenomena cited, including the relation of fjords tofaults, find a logical interpretation. It should be noted that the subsidence of the land, which wasan essential element of the theory that fjords are drowned normalriver valleys, ha^s been specifically invoked or tacitly assumed bymany of the supporters of the tectonic and glacial may be said regarding the discarded tectonic theory,it is clearly an error of reasoning which would assume the neces-sity of land sinking in order to account for partial submergenceof glacially over-deepened valleys. Glaciers in high latitudesreach the sea at the present time; and
Size: 960px × 2604px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, bookpublisheretcetc, bookyear191
