According to my family group sheet for this couple, they were married 5 Oct 1875 in Saint Louis, MO. She was born there 25 Dec 1855. I have a copy of their marriage record. His name is spelled Siek, but I am sure it is them.
I also have a copy of a church record pertaining to Johann Wilhelm Carl Obermeyer and his wife, Johanna Sophia (nee Knorr )and their first born, Wilhelm Gottfried Michael who was born 3 Jan 1848 . Itr shows that Johann Wilhelm Carl Obermeyer was Baptised in the city Braunschweig in Germany and Johanna Sophis KNORR was Baptized in Goeritzhain, Saxony, Germany
I have twenty-three family group sheets peraining to the descendants of this Sieck-Obermeyer marriage. Most of the data was given to me by the late Roy N. Restall whose mother considered herself the family's historian; unfortunately he did not share his documentation. Copies of these are yours for the asking. Or if you prefer I can supply you with the sheets pertaining only to your lineage.
I have identified Johann Heinrich (aka John Henry) Sieck as the son of Adolph Clamor Heinrich Sieck who was born in Huesede, Hannover, Germany and Florentine Luisa/Louise Ebeler who was born in Buer Amt Melle, Hannover, Germany. For years I have been trying to document the Sieck genealogy which traces Adolph Clamor Heinrich Sieck's ancestry back to his father Christof Heinrich Sieck of Huesede---but that is another story.
Let me know the scope of your interest and your postal address via e-mail and I will put together a mailing for you.