A strontium isoscape of inland southeastern Australia
<p>The values and distribution patterns of the strontium (Sr) isotope ratio <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M1" display="inline" overflow="scroll" dspmath="mathml"><mrow...
| Main Authors: | , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2022-09-01
|
| Series: | Earth System Science Data |
| Online Access: | https://essd.copernicus.org/articles/14/4271/2022/essd-14-4271-2022.pdf |
| Summary: | <p>The values and distribution patterns of the strontium (Sr) isotope ratio
<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M1" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msup><mi/><mn mathvariant="normal">87</mn></msup><mi mathvariant="normal">Sr</mi><msup><mo>/</mo><mn mathvariant="normal">86</mn></msup><mi mathvariant="normal">Sr</mi></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="49pt" height="15pt" class="svg-formula" dspmath="mathimg" md5hash="7f4baae305f328d12fa7f61ee32c1202"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="essd-14-4271-2022-ie00001.svg" width="49pt" height="15pt" src="essd-14-4271-2022-ie00001.png"/></svg:svg></span></span> in Earth surface materials are of use in the geological,
environmental, and social sciences. Ultimately, the <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M2" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msup><mi/><mn mathvariant="normal">87</mn></msup><mi mathvariant="normal">Sr</mi><msup><mo>/</mo><mn mathvariant="normal">86</mn></msup><mi mathvariant="normal">Sr</mi></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="49pt" height="15pt" class="svg-formula" dspmath="mathimg" md5hash="fc572d0bea75b4287a5b3ee79eca9f85"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="essd-14-4271-2022-ie00002.svg" width="49pt" height="15pt" src="essd-14-4271-2022-ie00002.png"/></svg:svg></span></span> ratios
of soils and everything that lives in and on them are inherited from the rocks
that are the parent materials of the soil's components. In Australia, there
are few large-scale surveys of <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M3" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msup><mi/><mn mathvariant="normal">87</mn></msup><mi mathvariant="normal">Sr</mi><msup><mo>/</mo><mn mathvariant="normal">86</mn></msup><mi mathvariant="normal">Sr</mi></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="49pt" height="15pt" class="svg-formula" dspmath="mathimg" md5hash="e4467c5528b2ace664e23d19756eb310"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="essd-14-4271-2022-ie00003.svg" width="49pt" height="15pt" src="essd-14-4271-2022-ie00003.png"/></svg:svg></span></span> available, and here we
report on a new, low-density dataset using 112 catchment outlet (floodplain)
sediment samples covering 529 000 km<span class="inline-formula"><sup>2</sup></span> of inland southeastern Australia
(South Australia, New South Wales, Victoria). The coarse (<span class="inline-formula"><i><</i>2</span> mm)
fraction of bottom sediment samples (depth <span class="inline-formula">∼</span> 0.6–0.8 m) from
the National Geochemical Survey of Australia were milled and fully digested
before Sr separation by chromatography and <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M7" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msup><mi/><mn mathvariant="normal">87</mn></msup><mi mathvariant="normal">Sr</mi><msup><mo>/</mo><mn mathvariant="normal">86</mn></msup><mi mathvariant="normal">Sr</mi></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="49pt" height="15pt" class="svg-formula" dspmath="mathimg" md5hash="d08d238405a8ea6b7e7b29972a1ba7ec"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="essd-14-4271-2022-ie00004.svg" width="49pt" height="15pt" src="essd-14-4271-2022-ie00004.png"/></svg:svg></span></span> determination
by multicollector-inductively coupled plasma mass spectrometry. The results
show a wide range of <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M8" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msup><mi/><mn mathvariant="normal">87</mn></msup><mi mathvariant="normal">Sr</mi><msup><mo>/</mo><mn mathvariant="normal">86</mn></msup><mi mathvariant="normal">Sr</mi></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="49pt" height="15pt" class="svg-formula" dspmath="mathimg" md5hash="5260b111447fe6189885d1843a512fbf"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="essd-14-4271-2022-ie00005.svg" width="49pt" height="15pt" src="essd-14-4271-2022-ie00005.png"/></svg:svg></span></span> values from a minimum of 0.7089 to
a maximum of 0.7511 (range 0.0422). The median <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M9" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msup><mi/><mn mathvariant="normal">87</mn></msup><mi mathvariant="normal">Sr</mi><msup><mo>/</mo><mn mathvariant="normal">86</mn></msup><mi mathvariant="normal">Sr</mi></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="49pt" height="15pt" class="svg-formula" dspmath="mathimg" md5hash="2bd05feaa19a0417bc7caaaba8485c45"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="essd-14-4271-2022-ie00006.svg" width="49pt" height="15pt" src="essd-14-4271-2022-ie00006.png"/></svg:svg></span></span> (<span class="inline-formula">±</span> median absolute deviation) is 0.7199 (<span class="inline-formula">± 0.0071</span>), and the mean
(<span class="inline-formula">±</span> standard deviation) is 0.7220 (<span class="inline-formula">± 0.0106</span>). The spatial
patterns of the Sr isoscape observed are described and attributed to various
geological sources and processes. Of note are the elevated (radiogenic)
values (<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M14" display="inline" overflow="scroll" dspmath="mathml"><mrow><mo>≥</mo><mo>∼</mo></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="19pt" height="10pt" class="svg-formula" dspmath="mathimg" md5hash="407a930bce85629226f77123f12d98cb"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="essd-14-4271-2022-ie00007.svg" width="19pt" height="10pt" src="essd-14-4271-2022-ie00007.png"/></svg:svg></span></span> 0.7270; top quartile) contributed by (1) the
Palaeozoic sedimentary country rock and (mostly felsic) igneous intrusions
of the Lachlan geological region to the east of the study area; (2) the
Palaeoproterozoic metamorphic rocks of the central Broken Hill region; both
these sources contribute radiogenic material mainly by fluvial processes;
and (3) the Proterozoic to Palaeozoic rocks of the Kanmantoo, Adelaide,
Gawler, and Painter geological regions to the west of the area; these sources
contribute radiogenic material mainly by aeolian processes. Regions of low
<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M15" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msup><mi/><mn mathvariant="normal">87</mn></msup><mi mathvariant="normal">Sr</mi><msup><mo>/</mo><mn mathvariant="normal">86</mn></msup><mi mathvariant="normal">Sr</mi></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="49pt" height="15pt" class="svg-formula" dspmath="mathimg" md5hash="e72675ce4dc97380507a29c15014c353"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="essd-14-4271-2022-ie00008.svg" width="49pt" height="15pt" src="essd-14-4271-2022-ie00008.png"/></svg:svg></span></span> (<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M16" display="inline" overflow="scroll" dspmath="mathml"><mrow><mo>≤</mo><mo>∼</mo></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="19pt" height="10pt" class="svg-formula" dspmath="mathimg" md5hash="fc3ae60215f1b0844788a2ac9936264e"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="essd-14-4271-2022-ie00009.svg" width="19pt" height="10pt" src="essd-14-4271-2022-ie00009.png"/></svg:svg></span></span> 0.7130; bottom quartile) belong
mainly to (1) a few central Murray Basin catchments; (2) some Darling Basin
catchments in the northeast; and (3) a few Eromanga geological
region-influenced catchments in the northwest of the study area; these
sources contribute unradiogenic material mainly by fluvial processes. The new
spatial Sr isotope dataset for the DCD (Darling–Curnamona–Delamerian) region is publicly available (de Caritat et al., 2022; <span class="uri">https://dx.doi.org/10.26186/146397</span>).</p> |
|---|---|
| ISSN: | 1866-3508 1866-3516 |