We present the bifurcation pattern of the thermocapillary horizontal convection flow of succinonitrile (SCN) in an open top parallelepipedic cavity with dimensions 4 x 1 x 1. The bifurcation parameter is the Rayleigh number (Ra) that was investigated in the range [150;5x 10(8)] while the Marangoni number (Ma) was kept at Ma= 10(4). Several steady flow configurations are described for Ra< or =5 x 10(7). Then the occurrence of periodic and quasiperiodic flows is shown for values of Ra<5 x 10(8) and at Ra=5 x 10(8) the chaos arises. It is also proved numerically the coexistence of different temporal regimes at the same value of Ra according to the thermal history of the fluid.