In the bustling coastal region of Xiamen Bay, Southeast China, a team of researchers has uncovered intriguing insights into the dynamics of saline geothermal waters, potentially reshaping how we harness these resources for energy. Led by Jing Li from the School of Environmental Studies at China University of Geosciences in Wuhan, the study delves into the formation, circulation, and age of geothermal waters, offering a fresh perspective on their interaction with seawater.
Geothermal energy, a renewable and sustainable resource, holds immense potential for meeting the world’s growing energy demands. However, the effective utilization of geothermal resources, particularly in coastal areas, has been hindered by a lack of understanding of their residence time and interaction with seawater. Li’s research aims to bridge this knowledge gap, providing valuable insights for the energy sector.
The study, published in the Journal of Hydrology: Regional Studies, focuses on granite-hosted coastal areas of Xiamen Bay. The researchers measured the chemistry and multiple isotopes of geothermal water samples, revealing that the saline geothermal waters in the region are of the chloride (Cl) type. “The enriched water isotopes and the co-variation of chloride and δ18O indicate a marine origin of salinity,” Li explained. This finding suggests that the geothermal waters have interacted with seawater, a process that has significantly influenced their composition.
The research also sheds light on the age of the geothermal waters. Carbon-14 isotope dating revealed that the age of fresh geothermal water ranges from 571 to 10,082 years in mountain areas and from 3,500 to 17,000 years in coastal areas. These age estimates imply a paleo-recharge in the fracture system, with mixing of ancient seawater trapped in the fractures during the Holocene and Late Pleistocene.
The implications of these findings for the energy sector are profound. Understanding the age and origin of geothermal waters can help in predicting their behavior and potential for energy extraction. Moreover, the study’s emphasis on long-term monitoring of geothermal water salinity is crucial for determining whether ancient seawater is a finite volume of storage or connects to the present seawater. This knowledge is vital for the scientific utilization of geothermal resources, ensuring their sustainable and efficient use.
Li’s research also highlights the importance of considering the geological context when exploring geothermal resources. The study’s findings suggest that the geological setting of Xiamen Bay, with its granite-hosted coastal areas, plays a significant role in the formation and circulation of geothermal waters. This insight could guide future geothermal exploration and development in similar geological settings.
As the world continues to seek sustainable energy solutions, the study of geothermal waters in coastal areas like Xiamen Bay becomes increasingly important. Li’s research offers a promising step forward, providing a deeper understanding of these complex systems and paving the way for their effective utilization. The study’s findings, published in the Journal of Hydrology: Regional Studies, are a testament to the power of scientific inquiry in driving innovation and progress in the energy sector.
