The sphere in SH that caused lines to radiate from Kelsier in every direction did so because it automatically strengthened his connection to any form of Preservation's investiture. When he pulled on these lines, he called the investiture into himself, causing his ascension. Basically, the sphere itself contained only connection, not large quantities of Preservation's investiture, but it allowed Kelsier to obtain enough investiture by pulling it to himself through his connection that he was able to ascend.
ETA: Because the spiritual realm, and therefore connection, is composed of investiture, the sphere could possibly be highly invested. It may not be Preservation's investiture, however, because we know investiture from different shards can substitute for each other (when disregarding intent). It most certainly could not have contained large amounts of Preservation, however, because such a discrepancy would undoubtedly be mentioned in the books