Origin of the sedimentary deposits of the Naracoorte Caves, South Australia, , Forbes Ms, Bestland Ea,

The origin of the sediments located in the Naracoorte Caves (South Australia) was investigated via the analysis of strontium isotope ratios (87Sr/86Sr), elemental geochemistry, and mineralogy. Sedimentary deposits located in Robertson, Wet, Blanche and several other chambers in Victoria Cave are all variable mixes of fine sand and coarse silts, which display similar and consistent strontium isotope ratios (0.717-0.725). This suggests that over the 400[no-break space]ka time frame that these deposits span there has been minimal variation in the source of the clastic sediments. Increased strontium concentrations for these cave sediments correspond with increasing silt content, yet there is no correlation between 87Sr/86Sr ratios and silt content. This implies that the silt-sized component of the sediments is the main contributor of strontium to the cave sediments. Comparisons of 87Sr/86Sr with regional surficial deposits show a significant correlation between the cave sediments (avg: 0.7228; n = 27), the fine silt lunettes of the Bool Lagoon area (avg: 0.7224; n = 4), the sandy A horizons of the Coonawarra Red Brown Earths (RBEs; avg: 0.726; n = 5), and Holocene age podsolic sand deposits (0.723). These data suggest that there has been substantial flux from this group of deposits to the caves, as would be expected considering prevailing winds. This relationship is further supported by a strong correlation between many trace elements, including Ti, Zr, Ce, and Y; however, variations in clay mineralogy suggest that the fine silt-dominated lunettes and Padthaway RBEs were not significant contributors to the cave deposits. Hence, the detritus entering the caves was more than likely from areas proximal to the cave entrance and was dominated by medium grain-sized materials. Major regional deposits, including the coarser-grained, calcite-rich Bridgewater Formation sands, basalts from the lower SE, Padthaway Horst granites, Gambier limestone, and metamorphics from the Adelaide geosyncline show minimal correlation in 87Sr/86Sr ratios, elemental geochemistry, and mineralogy with the cave sediments, and are discounted as significant sources. In comparison, 87Sr/86Sr ratios for the Coorong silty sands (0.717-0.724), Lower Murray sands (0.727-0.730), and the medium size silt component of the Murray-Darling River system (0.71-0.72), compare favourably with the cave sediments. This relationship is further supported by similarities in elemental chemistry and mineralogy. Thus, much of the strontium-rich silt that is now located in the Naracoorte Cave sediments likely originated from the Murray-Darling basin. Over time, this material has been transported to the SE of South Australia, where it mixed with the medium sand component of the regressive dune ridge sequence, locally derived organic matter, limestone fragments, and fossil material to produce the unique deposits that we see evident in many of the chambers of the Naracoorte Cave system today

The Historical Construction of Naracoorte Caves, 1986, Hamiltonsmith, Elery

This paper will focus upon the role of Reddan and Leitch, who between them were responsible for some 59 years of the first 62 years of cave management at Naracoorte. Those who seek a more comprehensive narrative of events, both prior to the first reservation and since, should consult the Draft Management Plan document (S.A. : National Parks and Wildlife Service, 1986).

Electron spin resonance dating of the fossil deposits in the Naracoorte Caves, South Australia., 2001, Grum R. , Moriarty K. , Wells R.

Cave Temperatures at Naracoorte Caves, 2002, Sanderson Ken , Bourne Steven

Temperatures in four different caves at Naracoorte were logged for periods of up to two years, during 1998-2001. In Bat Cave temperatures near ground level were 19.0-21.1°C in the maternity chamber, and 10.3-15.6°C near the entrance. In Victoria Fossil Cave temperatures near the fossil chamber were 16.9-18.3°C. In Blanche Cave and the outer chamber of Robertson Cave temperatures were 9.4-15.0°C, with temperatures in the inner chamber of Robertson Cave 14.2-15.0°C. Cave chambers with little air flow had seasonally stable temperatures, and those with high air flow showed seasonal temperature variations of 5-6°C.

Cave Temperatures at Naracoorte Caves, 2002, Sanderson Ken , Bourne Steven

Temperatures in four different caves at Naracoorte were logged for periods of up to two years, during 1998-2001. In Bat Cave temperatures near ground level were 19.0-21.1°C in the maternity chamber, and 10.3-15.6°C near the entrance. In Victoria Fossil Cave temperatures near the fossil chamber were 16.9-18.3°C. In Blanche Cave and the outer chamber of Robertson Cave temperatures were 9.4-15.0°C, with temperatures in the inner chamber of Robertson Cave 14.2-15.0°C. Cave chambers with little air flow had seasonally stable temperatures, and those with high air flow showed seasonal temperature variations of 5-6°C.

Bacterial community survey of sediments at Naracoorte Caves, Australia, 2012, Adetutu E. M. , Thorpe K. , Shahsavari E. , Bourne S. , Cao X. , Fard R. M. N, Kirby G. , Ball A. S.

Bacterial diversity in sediments at UNESCO World Heritage listed Naracoorte Caves was surveyed as part of an investigation carried out in a larger study on assessing microbial communities in caves. Cave selection was based on tourist accessibility; Stick Tomato and Alexandra Cave (> 15000 annual visits) and Strawhaven Cave was used as control (no tourist access). Microbial analysis showed that Bacillus was the most commonly detected microbial genus by culture dependent and independent survey of tourist accessible and inaccessible areas of show (tourist accessible) and control caves. Other detected sediment bacterial groups were assigned to the Firmicutes, Actinobacteria and Proteobacteria. The survey also showed differences in bacterial diversity in caves with human access compared to the control cave with the control cave having unique microbial sequences (Acinetobacter, Agromyces, Micrococcus and Streptomyces). The show caves had higher bacterial counts, different 16S rDNA based DGGE cluster patterns and principal component groupings compared to Strawhaven. Different factors such as human access, cave use and configurations could have been responsible for the differences observed in the bacterial community cluster patterns (tourist accessible and inaccessible areas) of these caves. Cave sediments can therefore act as reservoirs of microorganisms. This might have some implications on cave conservation activities especially if these sediments harbor rock art degrading microorganisms in caves with rock art.