1. How does a limestone cavern form? Include the history of the limestone. 2. Wh
ID: 289547 • Letter: 1
Question
1. How does a limestone cavern form? Include the history of the limestone.
2. What is the connection between chemical weathering and marine critters forming shells or the hard structure of coral? (Be specific about the type of weathering.)
3. What is fossil groundwater and what does it indicate about the geologic history of the Sahara region? Why should the groundwater under the Sahara Desert be considered a nonrenewable resource?
4. What is the relationship between thermohaline circulation and the ocean conveyor belt circulation?
Explanation / Answer
1). Limestones caves or the cavern are naturally formed underneath structures whose area of span varies from some meters to some kilometers, most of the world caves those on the cradle of the earth are formed of this, early life forms was appeared in the oceans about 3.8 million years ago and there was the cynobacteria which took their food by the process of photosynthesis and it releases the huge amount of oxygen that huge amount of oxygen was taken in reactions, limestones, the sedimentary rocks are deposited in the surface and formed the layered structures in this way, due to the movement in the earth crust the sedimentary rocks which were dumped were get exposrd on the surface and comes in contact with the atmosphere as the time passes the limestone comes in the contact with the water and thus causes erosion because it was permeable and soluble,Weak carbonic acid in rainwater, reacting with the chemicals in the rock, dissolved and eroded away the limestone as the water filtered into the underlying depths of sediments. Large hollow solution cavities were formed in the limestone in this way, and these cavities are called as cavern of limestones.
2).
The coral reefs are made up of the calcium carbonates which is subject to the chemical weathering thats why these reefs are broken down this process involves the formation of the carbonic acid by the mixture of water and the co2 from the atmosphere and then it settles over the reefs and thus reacts with the caco3 which causes chemical weathering.This type of addition of the carbonic acid leads to the acidification of the oceans.
Because of the adding of more and more carbonic acid the marine shells was formed by the clams, oysters, and some snails and urchins are getting partially dissolved because of the CO2 have 2 functions when it combines with the carbon of the ocean it formed the CACO3 from which these shells are formed but when it combines with water it forms H2CO3 which is an acid and thus it leads to the dissolution of the shells.
Some of the coral reefs are formed from stony corals, which consist of polyps that combines in groups. The polyps are from a group of animals known as Cnidaria, which also includes sea anemones and jellyfish. Unlike sea anemones, corals secrete hard carbonate exoskeletons which support and protect the coral polyps and thats why tthese coral reefs are hard in nature.
3).
Fossil water is found in the arid or semi arid region, where the climate was more humit in te recent history, In the recent history if the amount of precipitation is more than the amount of water which precipitates its most of the portion goes to the evaporation and some goes to the infiltration which leads to the recharge of the aquifers.Most of these fossil water were infilterated in within the Holocene and Pleistocene (10,000-40,000 years ago), and some part is associated with the melting of ice in the time since the last glacial maximum.Age of these sahara fossil water is determined by the dating of the isotopes such as 3H (tritium) and 18O ("heavy" oxygen), This water dissolves and bsorbs a number of ions from the host rocks in sahara regions because of such dissolution its salinity is higher than that of the oceanic water thats why the underground fossil wate of sahara region is salty in nature,some form of treatment is required to make these waters suitable for human use. Saline fossil aquifers can also store significant quantities of oil and natural gas
RENEWABILITY
Fossil water is extracted from these aquifers of sahara regions are for many human purposes, such as, agriculture, industry, and consumption. In arid regions, some aquifers containing available and usable water receive little to no significant recharge, effectively making groundwater in those aquifers a non-renewable resource.
Extraction rates greater than recharge rates result in lowering of the water table and can lead to groundwater depletion. Extraction of non-renewable groundwater resources is referred to as groundwater "mining" because of their finite nature.
4).
Thermohaline circulation is nothing but the circulation or the movement of the oceanic water due to the difference in temperature according to the latitudewise and thus this circulation creates salinity variations and which leads to the formation variations of the densities of the oceanic water this circulation traces a path which includes the Atlantic ocean, Indian ocean, antrctica ocean or the southern ocean and some part of the pacific ocean in which the water circulates by upwelling and downwelling at different places of low surface density and high surface density respectively and the path it traces is seems like two belts arraanged over one another and makes a system which looks like it is a moving conveyor thats why its name was given ocean conveyor belt circulation
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