Treacle is molasses, of which there are many different types, and it is caramelized many times for purposes of extracting sucrose, while maple syrup comes from the sap of maple trees. The maple sap is boiled down to create syrup.
Syrup is also available in different types, such as golden syrup, corn syrup, date syrup and grape syrup. Golden syrup is a refinery syrup in which raw sugar is used, and it is filtered through charcoal. Blackstrap molasses is the darkest form of treacle, and molasses is generally used in recipes for moisture, color and flavor rather than not sweetness. Sugar is often added to recipes using treacle.