inconspicuous
Really, the conditions were awfully awful. The new site for the rock garden was just a barren bit of grass, on a slope, facing the afternoon sun and perpendicular to the prevailing Spring gale. How, in an arboretum, are there no trees?
With a buffeting wind and unblinking glare, wrangling a heavy macro lens was never going to be fun. I still had the mewling and bawling toddler ringing in my ears as much as the roaring wind had my poor old ears drumming. Yet, in this maelstrom I was determined, for better or worse, to memorialise this rusty-looking nondescript boulder. It's actually worst. I should go back on a better day. Here's my dilemma. This rock is full of stories; but they are inconspicuous until someone tells them. This is the Middledale Diorite, source of one of the world's most widely used standards in U-Pb radiometric dating: Temora-2.
Part of the significance, to me at least, is that I spent a few mostly happy years quite near the source of this boulder. Temora had been a gold mining town. You know the drill: 20,000 people, 50 pubs, a main street built wide enough to turn a bullock dray because, well they could afford it, and everyone looking for their own version of the Mother Shipton nugget, then bust; only 7 pubs when I left. Sheep and wheat kept it alive, and the railway junction moved all of those riches, plus the produce of the Ardlethan tin mine and Murrumbidgee Irrigation Area off to distant markets. The railway's mostly gone now: roundhouse gone, turntable too, the big dam that watered the engines filled in, branch lines mostly closed. It struggles on. While all of this was happening, this boulder just sat inconspicuously on a hillside, out past the high school and hospital, waiting to be famous.
Here's my other distraction. There's another voice in my ear. I just happen to be trying to wrangle a front-heavy macro set up with my eyes watering in the gale and standing upright becoming a challenge when I hear someone ask: "Ah, you've found Temora-2?" Who could imagine that someone familiar with this blob of a boulder would turn up at just this moment? Yes, he said, I collected that, and use the zircons from it everyday in my work; we've got tonnes of it out the back…
That's the thing! This rusty boulder, and its siblings contain zircons which are uniformly 416.78±0.33 million years old. For someone interested in these things, a bit of this now certified standard is like Temora's gold. I recall, probably half a century ago now, when a distinguished and excited chap showed me where he was going to build the world's first effective ion microprobe for fine scale radiometric dating. He did it, without my help as I was just his visitor, and today it has evolved into a SHRIMP: Sensitive High-Resolution Ion Microprobe. A quiet one, he never skited about being NASA's choice to determine the age of moon rocks brought back by the Apollo missions, nor did he give up driving his distinctive Rover P3. He died in May this year, but his legacy lives on. Of course, to a familiar tune, it's another Aussie invention that's been sold to a Chinese buyer. But that piece of equipment is likely what has made this inconspicuous rock famous.
inconspicuous
Really, the conditions were awfully awful. The new site for the rock garden was just a barren bit of grass, on a slope, facing the afternoon sun and perpendicular to the prevailing Spring gale. How, in an arboretum, are there no trees?
With a buffeting wind and unblinking glare, wrangling a heavy macro lens was never going to be fun. I still had the mewling and bawling toddler ringing in my ears as much as the roaring wind had my poor old ears drumming. Yet, in this maelstrom I was determined, for better or worse, to memorialise this rusty-looking nondescript boulder. It's actually worst. I should go back on a better day. Here's my dilemma. This rock is full of stories; but they are inconspicuous until someone tells them. This is the Middledale Diorite, source of one of the world's most widely used standards in U-Pb radiometric dating: Temora-2.
Part of the significance, to me at least, is that I spent a few mostly happy years quite near the source of this boulder. Temora had been a gold mining town. You know the drill: 20,000 people, 50 pubs, a main street built wide enough to turn a bullock dray because, well they could afford it, and everyone looking for their own version of the Mother Shipton nugget, then bust; only 7 pubs when I left. Sheep and wheat kept it alive, and the railway junction moved all of those riches, plus the produce of the Ardlethan tin mine and Murrumbidgee Irrigation Area off to distant markets. The railway's mostly gone now: roundhouse gone, turntable too, the big dam that watered the engines filled in, branch lines mostly closed. It struggles on. While all of this was happening, this boulder just sat inconspicuously on a hillside, out past the high school and hospital, waiting to be famous.
Here's my other distraction. There's another voice in my ear. I just happen to be trying to wrangle a front-heavy macro set up with my eyes watering in the gale and standing upright becoming a challenge when I hear someone ask: "Ah, you've found Temora-2?" Who could imagine that someone familiar with this blob of a boulder would turn up at just this moment? Yes, he said, I collected that, and use the zircons from it everyday in my work; we've got tonnes of it out the back…
That's the thing! This rusty boulder, and its siblings contain zircons which are uniformly 416.78±0.33 million years old. For someone interested in these things, a bit of this now certified standard is like Temora's gold. I recall, probably half a century ago now, when a distinguished and excited chap showed me where he was going to build the world's first effective ion microprobe for fine scale radiometric dating. He did it, without my help as I was just his visitor, and today it has evolved into a SHRIMP: Sensitive High-Resolution Ion Microprobe. A quiet one, he never skited about being NASA's choice to determine the age of moon rocks brought back by the Apollo missions, nor did he give up driving his distinctive Rover P3. He died in May this year, but his legacy lives on. Of course, to a familiar tune, it's another Aussie invention that's been sold to a Chinese buyer. But that piece of equipment is likely what has made this inconspicuous rock famous.