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Post Info TOPIC: Australites
Blobrana


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Darwin glass
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Organics Preserved in Ancient Meteorite-Formed Glass

Scientists have found organics from Earth's swamp trapped inside of glass created by a meteor impact almost a million years ago. The tiny pockets, only micrometers across, contain material such as cellulose and proteins. Though the impact glass was found on Earth, scientists say that similar samples could have been thrown into space by this or other blasts, allowing organics to be transported from one planet to another.
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Blobrana


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RE: Australites
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Title: Review of the Australasian Tektite Source Crater Location and Candidate Structure in the Song Hong-Yinggehai 
Authors: A. Whymark

The Australasian tektite strewn field is the youngest of the major strewn fields. Tektites fell over 16-18 percent of the Earth's surface. The distal ejecta has a strongly down-range distribution pattern, indicative of an oblique impact from the northnorthwest. The estimated size of the source crater is ~40 km diameter, based on a calculated ejecta layer thickness from microtektite concentrations. Evidence is reviewed, a general source crater location suggested and a strong candidate structure identified.
The older/deeper buried the source material is, the lower the 10Be concentration. Tektite 10Be iso-concentration maps can be drawn up. These indicate the source crater is on the eastern side of the Indochinese Peninsula or in the Gulf of Tonkin, centred on 17° N, 107°E

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Tonkinb.jpg



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Blobrana


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Magical meteorite market bustling

The ad pieces about the sale of meteorites have appeared on some Russian websites. Meanwhile, in Vietnam, these "stones from the sky" have been traded for the last tens of years.
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Blobrana


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Darwin crater is a suspected meteorite impact crater in Western Tasmania, Australia. It is expressed as a 1.2 km diameter rimless circular flat-floored depression within mountainous and heavily forested terrain 26 km south of Queenstown. It lies east of the West Coast Range and just within the Franklin-Gordon Wild Rivers National Park.

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Darwincraterb.jpg
Expand (152kb, 776 x 592)

 Latitude: 42°18'15.14"S, Longitude: 145°39'32.57"E

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Blobrana


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Darwin Crater.kmz

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Blobrana


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Posts: 131433
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How old are tektites?
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Tektites are geologically young, with a range of about 300,000 years to 35 million years. Many Australites are 610,000 to 750,000 years old. The North American tektites have been dated at 34.5 million years, and the Libyan Desert glass at 28 million years. The Bohemian and Moravian sites are dated at 14.7 million years, Aouelloul Crater at 3 million years and Ivory Coast tektites at about 1 million years.

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Blobrana


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RE: Australites
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Title: Occurrence, distribution, and age of Australian tektites
Authors: Chalmers, R. O.; Henderson, E. P.; Mason, B.

Geographic distribution, relative abundance, physical properties, and chemical composition of australites (Australian tektites) were studied. Tektites were found in late Pleistocene or early Recent sandy aeolianite; the presence of delicate surface features on many tektites suggests that these tektites have not been subjected to terrestrial forces which would have relocated them. The stratigraphic findings indicate an age of 7000 to 20,000 years before the present, although K-Ar and fission track data are consistent with an age of about 700,000 years. Distribution within the strewn-fall is irregular and is attributed to original nonuniform fall, burial by recent deposition, or removal by erosion. Variations in chemical composition and size with respect to geographic distribution are also discussed.

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Image1
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The most striking of these bands of 'dense patches' is that of f - g which traversed some of the most famous and dense australite localities. If this line is continued to the north west it will be found to go directly to Indochina and the locality of the Muong Nong tektites and passes very close to the suspect impact crater of Tonle Sap!
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Blobrana


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Title: Source of the Australasian tektite strewn field - A possible off-shore impact site
Authors: Schnetzler, C. C.; Walter, L. S.; Marsh, J. G.

Although there is a preponderance of evidence that tektites were formed by asteroid impacts on the earth, no source crater has been found for the largest and youngest of the strewn fields - the Australasian strewn field. A combined Seasat/Geos 3 altimeter data set of sea surface heights in the northern portion of the Australasian strewn field has been examined for negative gravity anomalies on the continental shelf and slope which might be related to the source crater for these tektites. A large negative anomaly called the Qui Nhon Slope Anomaly is a sea surface depression of approximately 1.5 meters over an area of 100 km diameter. It corresponds to a gravity anomaly of about -50 mgal. It is proposed that this anomaly may be due to the impact structure that produced the Australasian strewn field.

Source

110.62315E_13.77877N
Expand (27kb, 804 x 566)
Location map overlain with gravity anomaly map

Latitude:13.78 Longitude: 110.62


The Tonle Sap, 35x100 km, structure was proposed as the origin of the tektites.  The structure is associated with -3 to -4 mgal gravity anomaly.
Possibly the same as Qui Nhon.
Latitude:12.80 Longitude: 104.12

References:
Moilanen J. (2004) List of probable and possible impact structures of the World. 29 October 2004.
Source (829kb, XLS)

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Blobrana


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Tektites are found in geographically restricted areas and are associated with asteroid or comet impact with the Earth. A number of previous hypotheses were put forward, including a lunar origin (from lunar volcanoes or lunar impact events). These alternatives are no longer taken seriously by scientists. It has been firmly established that tektites are terrestrial rock melted and flung into the atmosphere by the force of an asteroid or comet impact. Whilst a number of tektite strewn fields exist, the focus of this website is the Australasian strewn field. This is the most recent strewn field, the largest and is unique due to the low angle impact, which resulted in the formation of highly oriented forms typified by the much sought after flanged Australite buttons.

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Blobrana


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Darwin Crater
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145.66030E_42.30428S

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