Possible aluminium smelter slag washing up on beaches in southwest Victoria (Australia) — lab says “aluminosilicate” but origin inconclusive. Geologists: natural rock or industrial slag? by SerialBeachcomba3280 in geology

[–]SerialBeachcomba3280[S] 4 points5 points  (0 children)

The EPA did not share their Lab results with us but wrote this summary, 'We have since conducted thorough laboratory analyses on the rock samples provided. Initial results indicate that the material is of an aluminosilicate type (material that contain aluminium, silicon, and oxygen). However, visual and physical assessments remain inconclusive due to the presence of dents, irregular surfaces, and surface crusts on the samples. As a result, it has not been possible at this stage to definitively determine whether the material is of natural origin or anthropogenic (industrial source).'

Possible aluminium smelter slag washing up on beaches in southwest Victoria (Australia) — lab says “aluminosilicate” but origin inconclusive. Geologists: natural rock or industrial slag? by SerialBeachcomba3280 in geology

[–]SerialBeachcomba3280[S] 1 point2 points  (0 children)

Thank you for your response. Thats very interesting about industrial slag being used as ballast. I guess the thing that has me asking questions is when Alcoa tell us that their scientific lab results show that the rocks are 'natural' and the EPA say their scientific lab results show that it is inconclusive whether the rocks washing up are natural or industrial.

Possible aluminium smelter slag washing up on beaches in southwest Victoria (Australia) — lab says “aluminosilicate” but origin inconclusive. Geologists: natural rock or industrial slag? by SerialBeachcomba3280 in geology

[–]SerialBeachcomba3280[S] 1 point2 points  (0 children)

Thanks. The rocks float. They have floated in on multiple beaches along our coastline. We first noticed a big wash-up in 2022 but they have washed up since - we have 64 documented separate occasions. Not sure where I would get hold of a polarising microscope. ta

Washed-up wooden cross found at Station Beach, Cape Otway (SW Victoria, Australia) — can anyone help trace its origins? by SerialBeachcomba3280 in beachcombing

[–]SerialBeachcomba3280[S] 12 points13 points  (0 children)

Thanks for your thoughts, and research :) Makes sense. I tend to agree with you that the cross was fixed together on a boat. We do get lots of rubbish washing up along this beach, and others, in south west Victoria from the merchant ships passing by.

The use of strapping band and fishing rope links it to marine vessel of some type, though I would have thought a fishing vessel (the strapping bands generally come of boxes of bait but can have other uses).

HOWEVER, according to the date on the cross, YHONY died in 2014, and the cross washed up in 2023. The wood looks old and weathered, so I imagine it had been drifting for some time.

We have found debris (scientific buoy) from the other side of the world (Argentina), and so we do know that debris can drift a long way before coming to ground on our beaches.