Applied sedimentology

[6jan14Sn vbm] Alexander & Fielding (1997) have described gravel antidunes in the modern Burdekin river ofQueensland, Australia. Fig 5.20 illustrates an example from an ancient alluvial environment [p.149-150]

@Depositional systems [p.181]
#~~ the depositional system approach [pendekatan] to understanding the origins of sedimentary rocks. In this method the ancient depositional envi (process) of a sedimentary rock (the product) is deduced [menyimpulkan] by comparison w/ modern depositional envi

@Physiographic units [p.181]
#The surface of the earth can be clasified by geomorphlogists into distinctive PHYSIOGRAPHIC units, such as mountain ranges, sand deserts & deltas. Similarly, oceanographers define morphologic types of sea floors such as continental shelves, submarine fans & abyssal plain. The most cursory [singkat, sepintas] of such studies shows that the number of physiographic types is finite [terbatas]. For example, lakes & deltas occur on most of the continents; submarine fans & coral reefs are spread wide across the oceans.

@Def sedimentary envi
#It has been defined as a “part of the earth’s surface which is physically, chemically & biologically distinct from adjacent [bedekatan, berdampingan] areas (Selley 1970:1 in p.181). As already pointed out, sand deserts, deltas & submarine fans are examples of these different sedimentary envi

@Soil formation [p.182-183]
#prolonged [yg berlangsung lama] exposure [kedapatan, pembukaan] to the elements is responsible for the development of weathering profiles & soil formation in the rocks which immediatelly underlie [mendasari] an envi of equilibrium (Thiry & Simmon-Coincon 1999). Laterite & bauxite horizons are the products of certain specific climatic conditions in conjunction w/ [dlm hubx dg, ber-sama2 dg] suitable [cocok, sesuai] rock substrates [landasan] (see section 2.3.3). They may be regarded as the products of sedimentary envi of equilibrium [keseimbangan]

@Classical type of classification of sedimentary envi [p.184]
#a second reason why this classification (tab 6.2) is difficult to apply to ancient sediments is because it is extremely hard [sukar] to determine the depth of water in which ancient marine deposits originated. It is generally
possible to recognize the relative position of a sequence of facies w/ respect to a shoreline [grs pantai], but it is often extremely hard to equate [menyamakan] these w/ absolute depths (Hallam 1967:330 in p.184). For this reason a classification of marine env into depth-defined neritic, bathyal & abyssal realms [alam, bidang, kalangan] is hard to apply to ancient sediments


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