2D thermal modelling along the seismic section Kuppam–Bommidi in Southern Granulitic terrain of Indian Shield,Journal of Earth System Science

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2D thermal modelling along the seismic section Kuppam–Bommidi in Southern Granulitic terrain of Indian Shield
Journal of Earth System Science ( IF 1.9 ) Pub Date : 2020-10-24 , DOI: 10.1007/s12040-020-01481-2
Harini Guruhappa , G N Shinde , T Vijay Kumar , D V Ramana , Kirti Srivastava

Abstract

The crustal structure along the 90 km seismic profile from Kuppam to Bommidi in the southern part of Archean Dharwar Craton and Southern Granulitic terrain is used to obtain a 2D thermal structure for the region. The temperatures are computed for known values of the radiogenic heat production, thermal conductivity and associated boundary conditions. The heterogeneous nature of the subsurface compels one to consider the controlling parameters to be a realization of a random process, as estimation of realistic values for these parameters is very difficult. Uncertainties in the model in such a situation can be analyzed by solving the governing heat conduction equation with its associated boundary conditions from a stochastic point of view. A 2D thermal model for this area is obtained using the finite element method for the heat conduction problem using the COMSOL Multiphysics software. The crustal temperatures for different layers along the 90 km profile is computed by incorporating randomness in thermal conductivity values. Using seismic velocities, the heat production in the layered earth is computed along the profile. The 2D temperature-depth profile along with upper and lower bounds is plotted and results obtained reveal that the temperature varies from 405° to 498°C at Moho depth along the profile. The errors are varying from 100° to 115°C. The Moho depth along the profile is seen to vary from 34 to 45 km. At a few locations, the 1D solution along with error bounds is plotted and the results are seen to match well with that of the 2D thermal result at that location.

Highlights

The 2D crustal thermal structure along with its errors is computed along the 90 km Kuppam–Bommidi profile is the Southern Granulite Terrane.
The crustal thermal structure for this profile is solved using the finite element method for the heat conduction problem with surface temperature as one boundary condition and mantle heat flow values as lower boundary conditions and incorporating thermal parameters such as thermal conductivity and heat production along the profile.
Variation in thermal structure for changes in thermal conductivity is calculated by incorporation randomness in thermal conductivity values.
The crustal temperature varies from 405°C to 498°C at Moho depth along the profile. The errors are varying from 100°C to 115°C. The Moho depth in the region varies from 34 to 45 km.

中文翻译：

印第安盾构南部花岗岩地带Kuppam–Bommidi地震剖面的二维热模拟

摘要

从太古宙达顿克拉通南部的库帕姆到博米迪，沿着90公里地震剖面的地壳结构被用来获得该地区的二维热力结构。计算温度以获取已知的放射源热产生值，热导率和相关的边界条件。地下的异质性迫使人们认为控制参数是随机过程的实现，因为估计这些参数的实际值非常困难。在这种情况下，模型的不确定性可以通过从随机的角度求解控制热传导方程及其相关边界条件来分析。使用COMSOL Multiphysics软件使用热传导问题的有限元方法获得了该区域的二维热模型。沿90 km剖面的不同层的地壳温度是通过将热导率值中的随机性纳入计算的。使用地震速度，沿着剖面计算层状地球中的热量产生。绘制了二维温度-深度曲线以及上下边界，获得的结果表明，沿该曲线在莫霍深度处温度在405°至498°C之间变化。误差范围为100°至115°C。沿剖面的莫霍面深度从34公里到45公里不等。在几个位置上，绘制了1D解以及误差范围，并且结果与该位置的2D热结果十分吻合。