Physical Modeling of Fold-and-Thrust Belt Evolution and Triangle Zone Development:Dabashan Foreland Belt(Northeast Sichuan basin,China) as an Example

Triangle zones, generally found in foreland fold-and-thrust belts, serve as favorable objects of petroleum exploration. Taking the Dabashan foreland belt as an example, we studied the formation and development of triangle zones, and investigated the effect of d^collements and the mechanical contrast of lithology by employing the method of physical modeling. Four experimental models were conducted in the work. The results showed that ＇sand wedges＇ grew episodically, recorded by deformational length, height and slope angle. The height versus shortening rate presented an S-shape curve, and uplifting occurred successively in the direction of the foreland belt. During the formation of the triangle zone, layer-parallel shortening took place at the outset; deformation decoupling then occurred between the upper and lower brittle layers, divided by a middle-embedded silicone polymers layer. The upper brittle layers deformed mainly by folding, while the lower sand layers by thrusting. As shortening continued, the geometry of a triangle zone was altered. We consider that the triangle zone in the Dabashan foreland belt was modified from an early one based on available seismic profiles and the experimental results. In addition, dccollements and mechanical contrast impose significant influence on structural development, which can directly give rise to structural discrepancies. More d^collements and obvious mechanical contrast between brittle layers can promote the coupling between the upper and lower brittle layers. Basal d^collement controls the whole deformation and decreases the slope angle of the wedge, while roof d^collement determines whether a triangle zone can be formed.

REGIONAL TOURISM COOPERATION IN TRIANGLE ZONE OF LIAONING PROVINCE

Strengthening the regional tourism cooperation is the requirement of both tourism development and tourist competition drive. On the one hand, resources, products, market and infrastructure in tourism are characteristics of half-public goods, which are the externalities. On the other hand, tourism competition has evolved from individual scenic spot, or finn competition to regional competition, which also requires urgent regional tourism cooperation. In recent years, the regional economic cooperation has been becoming popular in the world. The triangle tourism zone of Liaoning Province, constituted by Shenyang, Dalian and Dandong, is the core region of Liaoning tourism system. This regional tourism cooperation has been raised for a long time, but has not made substantial progress as yet. In recent years, the strategic cooperation among them has been becoming urgent, along with the change of tourism competition models, as well as the desire for building a Northeast Asia tourist economy circle. Based on literature, this paper establishes a conceptual frame of regional tourism cooperation and applies it in the analysis of the strategic tourism cooperation of Liaoning Province＇s golden triangle zone. This paper firstly examines both qualifications and motives concerning with cooperation among the three cities, and believes that the biggest difficulties involve traditional ideas, administrative institutions, communications, economic performances, time constraints, and more overlap among their tourist markets. Then this paper continues to construct a cooperating mechanism, including participant arrangements, construction of operating mechanism and construction of assisting mechanism. At last, this paper proposes approaches to the strategic cooperation such as introducing Xiuyan County, strategic integration and developing differentiated and complemented tourism products.