The distribution and roost habitat of the orange leaf-nosed bat, Rhinonicteris aurantius, in the Pilbara region of Western Australia

2001 ◽  
Vol 28 (1) ◽  
pp. 95 ◽  
Author(s):  
K. N. Armstrong
Keyword(s):  
Western Australia ◽  
Nature Reserve ◽  
Iron Formation ◽  
Banded Iron Formation ◽  
Diverse Range ◽  
Breeding Range ◽  
New Localities ◽  
Orange Leaf ◽  
First Time ◽  
Landform Units

The endemic orange leaf-nosed bat, Rhinonicteris aurantius, is a relict both in a phylogenetic and a geographic sense. Prior to this study, two colonies in disused mines and seven other records of single animals were known from the disjunct Pilbara population of Western Australia. Cave roosts were located in the region for the first time, five new roosts were found in disused mines and the species was recorded in five new localities. Cave roosts were discovered in sandstone bedding. Free-flying R. aurantius were located in a diverse range of landscapes composed of banded iron formation, Cleaverville Formation geology and granite. Mines utilised as roosts were structurally complex and in some cases breached the watertable. This study revealed that while the species is widespread throughout the region, it is restricted to certain landform units, the number of suitable roosts within landform units is limited and the population appears to be subdivided within the region. Dispersal and connectivity within the population may be dependent on the availability of roosts in intervening areas, which may be a function of the availability of groundwater to subterranean formations for the control of roost microclimate. Currently, the known breeding range is one gorge at Barlee Range Nature Reserve and one mine at Bamboo Creek.

scholarly journals Archean to Paleoproterozoic seawater halogen ratios recorded by fluid inclusions in chert and hydrothermal quartz

2020 ◽  
Vol 105 (9) ◽  
pp. 1317-1325
Author(s):  
Ray Burgess ◽  
Sarah L. Goldsmith ◽  
Hirochika Sumino ◽  
Jamie D. Gilmour ◽  
Bernard Marty ◽  
...  
Keyword(s):  
Western Australia ◽  
Fluid Inclusions ◽  
Hydrothermal Systems ◽  
Iron Formation ◽  
Banded Iron Formation ◽  
Hydrothermal Quartz ◽  
Ocean Salinity ◽  
Halide System ◽  
Chemical Sediment ◽  
Substantial Change

Abstract Past changes in the halogen composition of seawater are anticipated based on the differing behavior of chlorine and bromine that are strongly partitioned into seawater, relative to iodine, which is extremely depleted in modern seawater and enriched in marine sediments due to biological uptake. Here we assess the use of chert, a chemical sediment that precipitated throughout the Precambrian, as a proxy for halide ratios in ancient seawater. We determine a set of criteria that can be used to assess the primary nature of halogens and show that ancient seawater Br/Cl and I/Cl ratios can be resolved in chert samples from the 2.5 Ga Dales Gorge Member of the Brockman Banded Iron Formation, Hamersley Group, Western Australia. The values determined of Br/Cl ~2 × 10-3 M and I/Cl ~30 × 10-6 M are comparable to fluid inclusions in hydrothermal quartz from the 3.5 Ga North Pole area, Pilbara Craton, Western Australia, that were the subject of previous reconstructions of ancient ocean salinity and atmospheric isotopic composition. While the similar Br/Cl and I/Cl values indicate no substantial change in the ocean halide system over the interval 2.5–3.5Ga, compared to modern seawater, the ancient ocean was enriched in Br and I relative to Cl. The I/Cl value is intermediate between bulk Earth (assumed chondritic) and the modern seawater ratio, which can be explained by a smaller organic reservoir because this is the major control on marine iodine at the present day. Br/Cl ratios are about 30% higher than both modern seawater and contemporary seafloor hydrothermal systems, perhaps indicating a stronger mantle buffering of seawater halogens during the Archean.

scholarly journals Serra Sul diamictite of the Carajás Basin (Brazil): A Paleoproterozoic glaciation on the Amazonian craton

Geology ◽  
2019 ◽  
Vol 47 (12) ◽  
pp. 1166-1170 ◽  
Author(s):  
Raphael Araújo ◽  
Afonso Nogueira
Keyword(s):  
South America ◽  
Volcanic Rock ◽  
Iron Formation ◽  
Banded Iron Formation ◽  
Submarine Fan ◽  
Glacial Deposits ◽  
Amazonian Craton ◽  
Ice Rafting ◽  
First Time

Abstract This paper reports the discovery of glacial deposits of likely Siderian–Rhyacian age (2.58–2.06 Ga) in South America (Carajás Basin, Brazil), thereby expanding the potential reach of Paleoproterozoic glaciations to the Amazonian craton for the first time. Glacially derived diamictites are stacked within a hitherto unrecognized ∼600-m-thick siliciclastic succession, here named the Serra Sul Formation. Well-preserved textures, with evidence of glaciotectonism and ice rafting, indicate deposition in a coastal subglacial to glacial-fed submarine fan system, in which the immediately underlying units (banded iron formation and volcanic rock) were the main source and bedrock. The Serra Sul diamictite may be correlated with any of the known Paleoproterozoic glaciations, or with none of them.

The Joffre banded iron formation, Hamersley Group, Western Australia: Assessing the palaeoenvironment through detailed petrology and chemostratigraphy

2016 ◽  
Vol 273 ◽  
pp. 12-37 ◽  
Author(s):  
Rasmus Haugaard ◽  
Ernesto Pecoits ◽  
Stefan Lalonde ◽  
Olivier Rouxel ◽  
Kurt Konhauser
Keyword(s):  
Western Australia ◽  
Iron Formation ◽  
Banded Iron Formation
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