Since 1935, when Oil Search Ltd. commenced its Hutton Creek well, six deep tests have been drilled to test folds in Permian strata in central Queensland. The wells are: 1. Oil Search Ltd.--Hutton Creek well 2. Oil Search Ltd.--Arcadia No. 1 well 3. Shell (Queensland) Development Pty. Ltd.--Morella well 4. Australasian Oil Exploration Ltd.--Reid's Dome No. 1 well 5. Australasian Oil Exploration Ltd.--Reid's Dome No. 2 well 6. Australasian Oil Exploration Ltd.--Consuelo well. The following is an attempt to divide the strata penetrated in the wells into formations defined by surface mapping and to correlate between the six wells. Electrical logging was carried out on all except the Oil Search Ltd. wells. The last four wells have been correlated by using these logs. A geological history of the area is presented together with a brief review of oil and gas possibilities. Throughout the text, discussion is confined to the area defined by the six wells.
<p>The oxygen isotope signature of leaf water is used to trace several processes at the soil-plant-atmosphere interface. During photosynthesis, it is transferred to the oxygen isotope signature of atmospheric CO<sub>2</sub> and O<sub>2</sub>, which can be used for reconstructing past changes in gross primary production. The oxygen isotope signature of leaf water additionally imprints leaf organic and mineral compounds, such as phytoliths, used as paleoclimate and paleovegetation proxies when extracted from sedimentary materials.</p><p>Numerous experimental and modelling studies were dedicated to constrain the main parameters responsible for changes in the &#948;<sup>18</sup>O of leaf water. Although these models usually correctly depict the main trends of <sup>18</sup>O-enrichment of the leaf water when relative humidity decreases, the calculated absolute values often depart from the observed ones by several &#8240;. Moreover, the &#948;<sup>18</sup>O of leaf water absorbed by plants is dependent on the &#948;<sup>18</sup>O value of meteoric and soil waters that can vary by several &#8240; at different space and time scales. These added uncertainties make our knowledge of the parameters responsible for changes in the &#948;<sup>18</sup>O of leaf water and phytoliths flawed.</p><p>Changes in the triple oxygen isotope composition of leaf water, expressed by the <sup>17</sup>O-excess, are controlled by fewer variables than changes in &#948;<sup>18</sup>O. In meteoric water the <sup>17</sup>O-excess varies slightly as it is weakly affected by temperature or phase changes during air mass transport. This makes the soil water fed by meteoric water and the atmospheric vapour in equilibrium with meteoric water changing little from a place to another. Hence the <sup>17</sup>O-excess of leaf water is essentially controlled by the evaporative fractionation. The latest depends on the ratio of vapor pressure in the air to vapor pressure in the stomata intercellular space, close to relative humidity. Leaf water evaporative fractionation can lead to <sup>17</sup>O-excess negative values that can exceed most of surficial water ones.</p><p>Here we present the outcomes of several recent growth chamber and field studies, for the purpose of i) refining the grass leaf water and phytoliths &#948;<sup>18</sup>O and <sup>17</sup>O-excess modelling, ii) assessing whether the &#948;<sup>18</sup>O and <sup>17</sup>O-excess of grass leaf water can be reconstructed from phytoliths, and iii) examining the precision of the <sup>17</sup>O-excess of phytoliths as a new proxy for past changes in continental atmospheric relative humidity. Atmospheric continental relative humidity is an important climate parameter poorly constrained in global climate models. A model-data comparison approach, applicable beyond the instrumental period, is essential to progress on this issue. However, there is currently a lack of proxies allowing quantitative reconstruction of past continental relative humidity. The <sup>17</sup>O-excess signature of phytoliths could fill this gap.</p>
