Application of sediment cores in reconstruction of long-term temperature and metal contents at the northern region of the Persian Gulf

Long marine sedimentary cores can be effective in paleo-climate reconstruction. The present research aims at analyzing the temporal variation of temperature as an important climate parameter and also variations in metal concentrations (As, Ba, Cd, Li, Mo, Mg, Mn, Na, Pb, Sr, Zn, Fe, Ca, Al) of two long sedimentary cores at the Persian Gulf back to the Holocene. The obtained results revealed that the average elemental concentrations, apart from Ni, Sr, Ca and Na, are less than the shale value in both sedimentary cores. Moreover, the amount of 𝛿13𝑐 varies from -1.31 versus 1.02 in Bushehr, to -1.69 versus 1.56 in Bandar Abbas sedimentary cores, respectively. In addition, 𝛿18𝑂 change from -3.63 Vs -2.02 in Bushehr to -3.79 Vs -1.36 in Bandar Abbas sedimentary cores, respectively. Abrupt change in 𝛿13𝑐 and 𝛿18𝑂 can be seen in both sedimentary cores at two different periods (3000 to 5000 and 8000 to 9000 years ago). The maximum increase in temperature in sedimentary cores was at 0.4°C per 100 years in Bushehr and 0.01°C per 100 years in Bandar Abbas. The minimum temperature reached to -0.8°C per 100 years in Bushehr to -0.02°C per 100 years in Bandar Abbas sedimentary cores. Compared to the previously obtained temperatures in this research, there has been temperature changes in the last 40 years in the Persian Gulf, which indicates that the recent rate change in sea water temperature has been unprecedented.