The Study of Gravity Low in Chutung Area

Shu-Fan Lin

Abstract

The Chutung gravity low is located the northwest in the Taiwan anomaly map (Yen et al., 1995). We can exclude artificial observation error form the Hsinchu Bouguer anomaly map (Chang, 1972) which is a result of gravity survey by Chinese Petroleum Corporation (CPC) in 1960s.There are many complex structures in this area because where is the interaction of inter and outer foothills.The oil and gas had found in the Chingtsaohu anticline, and Chutung anticline.There are many folds and faults.They are Hsinchu fault, Hsincheng fault, Chutung fault, Peipu fault, Juanchiao fault, Chingtsaohu anticline, Kantzechi syncline, Paoshan anticline, Chutung anticline, and Taping anticline in the Hsinchu area.The locations of the folds are related with the faults.The gravity located between Kuanhsi and Chutung area is related with the subsurface formation density.In this study, the geology model of Yang et al. (2002) is employed in constructing the initiate models.By combining the gravity data and the initiate models the low area is located from the west Paoshan anticline to the east Juanchiao fault.The gravity low area from the Paoshan anticline to the Peipu fault and from the Peipu fault to the Juanchiao fault are respectively arose by the Toukoshan formation and the complex structures. The depth of the Toukoshan formation is about 1.5 km.Due to a lot of logging and seismic data, the fitting between the observation and calculation of the gravity curve is great in the west part of the gravity low aera.However, the broken formation results in the bad fitting in the eastern part of the gravity low area.The east part of the gravity low, the initiate model needs to be correction. If we have more seismic and logging data in the eastern part, we will have the better result.

 

Reference

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(Abstract) (Full text)

Hsieh, S. H., Hu, C. C., 1972.Gravity and Magnetic Studies of Taiwan, Taiwan, Petrol. Geol. of Taiwan, no. 10, 283-321.

(Abstract) (Full text)