SE NW Pennyroyal Plateau Chester Upland Altitude Ieel melers 1000- 300 mainly in
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SE NW Pennyroyal Plateau Chester Upland Altitude Ieel melers 1000- 300 mainly insoluble rocks limestone-floored valley with sinkholes knob Green River 800 sinkholes Girkin Formation springs 600 200 St. Louis Limestone 400 MOTH CAVE 100 200 PEcave.htt avorago dp of rocks 1/3 to 1/2 degree FP :impure ro limestono 1 mile (1.5Km) approximate scale Image: Cross-section of Mammoth Cave Source: Anne Jefferson, adapted from Palmer, 1981 and obtained from http://www.nps.gov 1. Based upon the diagram above, how many major layers of passages are there? Based upon these major layers of cave passages, how many past base-levels (or water table levels) are recorded by the formation of Mammoth Cave? 2. What do you think caused these changes in base-level? (Hint: Think about the name "Pennyroyal Plateau" and "Chester Upland" 3.Explanation / Answer
At Mammoth Cave the limestone is topped by insoluble rocks, for the most part sandstone, which shape a safe top over the huge shakes beneath. This top shake secures the upper-level entries in the give in from being dissolved away. The stone layers are tilted a normal of around 0.3 degrees toward the northwest. The sandstone-topped district is known as the Chester Upland. It ascends to around 800 ft above ocean level. Stream disintegration has cut valleys into the caprock in numerous spots, leaving sporadic ?at-topped edges between them. Toward the south and east, where the caprock has been totally disintegrated away, the limestone is uncovered in a wide and almost ?at level, called the Pennyroyal Plateau, which lies around 150-200 ft beneath the edge peaks of the Chester Upland. It too is underlain by numerous hollows, and its surface is dimpled with a huge number of sinkholes. Sinkholes are dejections shaped by arrangement of the limestone by slipping water and fall of the limestone into hidden holes. All investigated entries of the Mammoth Cave System lie in the Chester Upland, however color following of underground water demonstrates that a considerable lot of the give in streams in the surrender are nourished by sinking streams and sinkholes in the Pennyroyal Plateau.
Entries in the give in have shaped not just by water from sinkholes in the Pennyroyal Plateau, yet additionally from stream valleys in the Chester Upland. A significant part of the water in these valleys enters along the dissolved edge of the sandstone top to shape little tributary sections. Most sections n Mammoth Cave have been relinquished by their streams. As the Green River valley develops by disintegration, more established sections lose their water to bring down courses, which shape new entries, while the more seasoned ones are left between a rock and a hard place.
Mammoth Cave contains a few kinds of entries. Over the water table (the level underneath which water fills all openings in the stone), the common sections are tight and gully like. They are higher than they are wide, with bending, twisted ways. These sections shape where the water depletes along the bedding (layering) of the stone, for the most part toward nearby plunge (tilt) of the beds. Their sinuosity is caused by anomalies in the neighborhood course of tilt. Gulches in Mammoth Cave extend up to 10-30 feet wide and up to 80-100 feet high, however most are much smaller and not all that high. Where water can plunge pretty much vertically along cracks, vertical shafts are framed. Shafts are for the most part round or oval in level cross segment and about all have created in stages by intermittent descending disintegration from bed to bed. Most shafts demonstrate an arrangement of channels at different heights in their dividers. Water dropping a pole today obviously exits by the most minimal deplete, which is situated at the pole floor. The biggest shafts in Mammoth Cave go up to 150 feet profound and a few many feet in measurement. Over the water table, water slips along the steepest accessible ways through the limestone. A large portion of the subsequent entries are ravines hindered in places along their length by shafts, to shape plunging stair-step profiles. Likewise shaped beneath the water table are entries that take after unmistakable fractures.These are straight, thin, and gap like. Numerous solutionally amplified breaks can be found in section roofs all over in Mammoth Cave, yet there are just a couple of little entries of this write can really be taken after.
Four past base levels are recorded by the formation of mammoth cave. These have been formed by incision of valleys by strems and rivers. Because of this cave levels are also formed.When there were events of rapid entrenchment, water was redirected through surface lows, rock fractures, and existing phreatic passageways. These actions led to cave collapse in some areas. The valley geomorphology is the result of base level lowering, stratigraphy, and insufficient time for valley widening. The lack of wide, gradually sloping valleys can also be explained by a short-lived constant base level during level formation and the high propensity for erosion within the valleys rather than the valley slopes. With increasing elevation, there is more likelihood that erosional processes have stepped the valley wall back further from the active stream channel.
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