Until recently it was believed that the earth had only experienced 4 to 5 glacial periods, all of which occurred in the past 2 million years. (Louis Agassiz, 1837) However, globally conducted research has revealed that countless glacial advances have appeared over 200 million years ago, thus broadening our insight of the history of the earth system by 100 times. These astonishing advances have witnessed the introduction of a new sub-discipline—palaeoclimatology, which specialises in the study of the climate prior to the period of instrumental measurements.
Importance and methodology of palaeoclimatology
As a matter of fact, knowledge about past climatic variations is invaluable to our lives today. The climate, in any region, is dynamic and …show more content…
(Bradley, 2015)
Data collection and calibration
Geological sediments
Geological evidence is the most widely distributed and commonly used approach to reconstruct the past climate. One of the essential way is the isotopic test. For example, the proportion of O18 in relation to O16 is temperature dependent in the organic compounds in the ocean. It has been proved that an increase of temperature by 1 °C is likely to cause a 0.23% decrease in the ratio of O18 to O16. The equation below shows how temperature is calculated from the isotopic ratio. (Craig, et al., 1963) Similar tests can be applied to TEX86, long chain diols, Mg/Ca abundance, sea ice proxies etc. to reconstruct …show more content…
For instance, globigerina has a peculiar character of bending its body to the left in warm water and to the right in the cold water. (Malmgren & Kennett, 1978) Sometimes, in cases where marine sediment comes from the comes the continent, we can obtain information of wind and precipitation.
Similarly, lake sediments, help to reconstruct a range of environmental conditions including temperature, salinity and even as dating methods. Lake sediment records have higher dating precision. As most lake sediments (varves, result from annual melting of ice sheets) accumulate at a high rate, which provides almost error free data and good consistency.
Assessments of sedimentary influx from the glacier is a prime data source regarding lake sediments. By examining the chemical constituents in the sediment, we can build a record of bedrock erosion by glacial activities. (Bilt, et al., 2015) Furthermore, there is also aeolian influx into the lake, which gives rise to modelling paleotemperature and wind activities. Other sources include macrofossils, the assemblage of ostracods— a microorganism which is sensitive to water depth and temperature; (Corrège, 1993) and that of diatoms regarding salinity, are all widely collected, and analysed through isotopic
Importance and methodology of palaeoclimatology
As a matter of fact, knowledge about past climatic variations is invaluable to our lives today. The climate, in any region, is dynamic and …show more content…
(Bradley, 2015)
Data collection and calibration
Geological sediments
Geological evidence is the most widely distributed and commonly used approach to reconstruct the past climate. One of the essential way is the isotopic test. For example, the proportion of O18 in relation to O16 is temperature dependent in the organic compounds in the ocean. It has been proved that an increase of temperature by 1 °C is likely to cause a 0.23% decrease in the ratio of O18 to O16. The equation below shows how temperature is calculated from the isotopic ratio. (Craig, et al., 1963) Similar tests can be applied to TEX86, long chain diols, Mg/Ca abundance, sea ice proxies etc. to reconstruct …show more content…
For instance, globigerina has a peculiar character of bending its body to the left in warm water and to the right in the cold water. (Malmgren & Kennett, 1978) Sometimes, in cases where marine sediment comes from the comes the continent, we can obtain information of wind and precipitation.
Similarly, lake sediments, help to reconstruct a range of environmental conditions including temperature, salinity and even as dating methods. Lake sediment records have higher dating precision. As most lake sediments (varves, result from annual melting of ice sheets) accumulate at a high rate, which provides almost error free data and good consistency.
Assessments of sedimentary influx from the glacier is a prime data source regarding lake sediments. By examining the chemical constituents in the sediment, we can build a record of bedrock erosion by glacial activities. (Bilt, et al., 2015) Furthermore, there is also aeolian influx into the lake, which gives rise to modelling paleotemperature and wind activities. Other sources include macrofossils, the assemblage of ostracods— a microorganism which is sensitive to water depth and temperature; (Corrège, 1993) and that of diatoms regarding salinity, are all widely collected, and analysed through isotopic