In 1940 he enlisted in the
Royal Australian Engineers, and worked with
munitions from 1941 to 1942. He transferred to the
soils division of the
CSIRO until 1943, when he joined the
South Australian Geological Survey, which sent him to reopen the
Radium Hill uranium field in 1944, and to map the
Mount Painter uranium field, new sources being required for the
Manhattan Project. Sprigg was sent by the
South Australian Government in 1946 to inspect abandoned mines in the
Ediacara Hills, to ascertain whether old mines could be reworked profitably using new technologies. When he discovered the fossils, apparently while eating his lunch, he realised that they were very ancient, either of Early
Cambrian, or possibly even of
Precambrian age. He thought that the organisms had probably been jellyfishes. He submitted a paper to the journal
Nature, but it was rejected. He travelled to London and presented his findings to the 1948
International Geological Congress, but failed to excite either interest or belief. Subsequent work by Prof
Martin Glaessner at the University of Adelaide demonstrated that they were indeed of latest
Precambrian age. Although Precambrian animal fossils had been reported before, they had not been accepted universally as organic. This discovery resulted ultimately in the definition in 2004 of the
Ediacaran Period, the first new
geological period created in more than one hundred years. Of other significance, Sprigg helped establish
Santos (an acronym for
South Australia Northern Territory Oil Search), which discovered gas deposits in the
Cooper Basin, including the
Moomba Gas Field, which supplies natural gas to South Australia,
New South Wales and
Canberra. In 1954 Sprigg formed the company Geosurveys of Australia, which was a consulting and contracting company for geological and geophysical work. They prospected for uranium in the
Northern Territory and
nickel in the north west corner area of South Australia as well as working for Santos. In 1962 Geosurveys became incorporated into
Beach Petroleum, of which Sprigg was general manager. In 1968, Sprigg purchased the pastoral lease of
Arkaroola, a property and important uranium exploration field of in the
Flinders Ranges of South Australia, and converted it into a wildlife refuge and tourist attraction. A governing board of Reg Sprigg, his wife Griselda and Dennis Walter, a mineralogist and old friend, oversaw the creation of Arkaroola Village out of existing buildings and the opening to tourists in October 1968. == Australian Energy Producers ==