Not really. There were 11 secession ordinances, and not one of them listed slavery as a cause. There were also four legislative declarations from four states, each of which listed slavery as a cause at length and one of which listed the tariff at length. As for there being an official statement of secession for the confederacy itself, there simply isn't one. Instead what you have are those documents I listed, dozens of newspaper editorials, and hundreds of speeches by prominent southerners in the government at the time such as the one found above.
"Our position is thoroughly identified with the institution of slavery --- the greatest material interest of the world. Its labor supplies the product which constitutes by far the largest and most important portions of of the commerce of the earth. These products are peculiar to the climate verging on the tropical regions, and by an imperious law of nature none but the black race can bear exposure to the tropical sun. These products have become necessities of the world, and a blow at slavery is a blow at commerce and civilization. That blow has been long aimed at the institution, and was at the point of reaching its consummation. There was no choice left us but submission to the mandates of abolition, or a dissolution of the Union, whose principles had been subverted to work out our ruin."
-- Mississippi secession document.
Well, you tipped my BS-O-meter.
Walt