Geochemistry and origin of tektites from Guilin of Guangxi,Guangdong and Hainan

Six tektites from Guilin of Guangxi, Hainan, and Guangdong were analyzed for the abundances of major elements and 27 trace elements. All samples are splash-form tektites and have SiO2 contents ranging from 73.1wt% to 76.0wt% (74.6wt% on average). The chemical compositions, except Cr and Ni, of tektites from different areas, are similar. Guangdong tektite shows enrichments of Ni and Cr contents by a factor of 3, and has slightly higher MgO and FeO than Hainan and Guilin tektites. It indicates that the tektites were formed by mixing several target rocks. The major and trace element concentrations of southern China tektites closely resemble previously reported data for average splash-form and Muong Nong-type indochinites, indicating that they have the same source. (La/Lu)CI (7.99), Zr/Hf (35.45 on average), Ba/Rb (3.59 on average), and the rare earth element (REE) contents of tektites are similar to those of typical post Archean upper crustal rocks. This study suggests that the best fit for the target source of southern China tektites could be a combination of 41% shale, 2% sandstone, 20% greywacke, and 37% quartzite.

A PRELIMINARY STUDY ON CHEMICAL COMPOSITION AND TL CHARACTERISTICS OF TEKTITES FROM LEIZHOU PENINSULA AND HAINAN ISLAND

Tektites have been found in many localities over the world, mainly in Asia-Australia, Cote Divoire, Moldavia and North America with isotopic ages of about 0.7, 1.1, 14.5 and 34.5 Ma respectively. Tektites in China are mainly distributed in the Leizhou Peninsula and Hainan Island. Recent discoveries of tektites in Maoming city, Dianbai and Yangjiang counties extend the spread area, which is now within the area of about 18020’—21°50’ N

Spratlies Archipelago as the Australasian Tektite Impact Crater, Details of Formation &Richard Muller’s Dust Cloud Explanation for the Mid-Pleistocene Ice Age Cycle Transition

Several significant events of a geological nature occurred approximately 800 ka before the present: (1) Australasian tektite fall (AA), (2) Brunhes-Matuyama geomagnetic reversal (BMR), (3) mid-Pleistocene changes in ice age cycles. Add to these the undated fault system (4) in the South-West (SW) of the South China Sea (SCS). Here we offer a unified cause for all four of these in (5), an impact in the SCS of a large, massive cosmic object, likely a comet, obliquely coming from the SW at an extremely shallow angle, striking the Sunda shelf yet unexploded with the shock of its compressed air bow wave, and causing the continual shelf and slope to collapse, resulting in the fault system (4), then traveling almost tangentially to the surface, exploding at impact with the sea surface, ejecting the tektites (1), creating the formation underlying the later atolls of Spratlies Archipelago (6), Nansha Islands in Chinese, & causing the BMR (2). An explanation of event (3) was Richard Muller’s hypothesis of planet Earth passing through an interplanetary dust cloud periodically due to ecliptic precession. Here we hypothesize this cloud actually is a belt of Australasian tektites ejected into space at super-orbital velocities that Earth encounters about every 100 ka.

Disintegrated Comet Trail in Southern Tibet

In southern Tibet, there is a series of lakes in the region (82°30'E, 29°N and 90°30'E, 33°N). This study indicates that these lakes were formed by the impact of a single disintegrating comet that hit the region. Observation indicates that the lakes are unusually closely aligned and have a steep slope facing circular feature on the eastern side. Fractures and faults connecting these lakes can be observed over entire subject site hinting towards the multiple impact craters. The terrain is uneven and lakes are partially filled hence in some cases do not look like circular or elliptical. These lakes vary from 1 Km to 65 Km in diameter and are linearly aligned around a single line. Studies of deuterium by Yuan et al. (2011) [1] indicate an abrupt 4‰ increase in δ18O in middle Holocene period around 6000 years ago. The study indicates that the region is rich in diamond, Coesite, Platinum Group Elements (PGE), Stishovite, tektites, and other complex alloys, as would be expected from a high energy impact of an extraterrestrial object. The possibility of the impact as one of the reasons for the diamond in this region was also suggested by Wen-Ji Bai and Qing-Song Fang (2007) [2]. However in absence of definitive evidence they favoured mantle origin. Two possible reasons of absence of impact signature are source of sample and impact pattern. First is the source of the sample which is collected from the river beds of Yarlung-Zangbo Suture Zone of Tibet which is believed to be the origin of this diamond, however it ignores the fact that these rivers get water from lakes which are in the proposed impact zone and the second reason is the impact-pattern spread over close to 800 km which is not expected from the asteroid impact. It will therefore be prudent to test samples from the lake region to understand surface distortion features to confirm the impact. Based on satellite imagery major industrial development supported by road infrastructure in the subject region near lakes and rivers originating from these lakes can be observed hinting towards placer mining activity associated with lakes (craters). Our study suggests that the diamonds, Platinum Group Elements, Stishovite and other alloys harvested from the region should be considered as comet impact diamonds rather than those created in the interior of the earth.

The Unique Comet Impact Pattern with Reference to Southern Tibet

In the terrestrial planet zone, Comets start outgassing due to solar radiation. This can make comet composition fragile enough to break under the gravitational gradient. Examples like those of Comet Shoemaker-Levy 9 [1] show that it is not unusual for comets to disintegrate due to gravitational gradients. In the event of an impact of such a disintegrated comet on earth, multiple coherent impact craters will be distributed over a large area. The low-density porous composition of the comet will result in the formation of “large flat-floored craters” spread over a large area with a network of faults and fractures as described by Roddy and co-workers (Roddy, 1976;Roddy et al., 1977) [2] [3]. Due to its unusual appearance these impacts patterns are different than rock/metal asteroid impact craters. As a result, these sites are difficult to identify. There are multiple such sites on the planet earth which are under study for impact but due to complex nature of comet impact craters, they have been a conundrum for some time. One such possible site matching the comet impact features can be observed in the southern Tibet between the latitudes of 82°30'E and 90°30'E and 29°N and 33°N. This study indicates that the lakes in this region were formed by the impact of a single disintegrating comet that hit the region. Observation indicates that the lakes are unusually closely aligned and have a steep slope facing circular feature on the eastern side. Fractures and faults connecting these lakes can be observed over entire subject site hinting towards the multiple impact craters. These craters are large flat-floored and spread over a large area. Gravitational anomaly in the lake region along with the presence of Ultra High Pressure (UHP) minerals like cubic Born Nitride, micro-diamond with the inclusion of Platinum Group Elements (PGE), coesite, Stishovite, osbornite and other complex finds in the region support the possibility of impact.

泰国东北部猜也奔府Noen Sa-nga地区Yasothon土壤剖面中的澳大拉西亚玻陨石(英文)

A sedimentary profile exposed in soil quarries a few kilometers north of Noen Sa-nga district,Chaiyaphum province,NE Thailand,reveals a Quaternary geological history.The lower part of the soil profile is a gravel deposit characterized by sub-angular to well-rounded pebbles representing an abandoned river sedimentary deposit.The gravel bed in some places is coated by iron oxide as a thin layer of ferricrete at the uppermost part.The upper part of the soil profile is a bright reddish brown structureless sand deposit with fining upward sedimentary structure at the basal portion,the Yasothon soil series.A piece of tektite was discovered at the contact boundary between the two sedimentary units.It is characterized by an irregular shape with a smooth concaved surface regarding as an external mold of a piece of well-rounded pebble.This piece of tektite indicates that a solidified tektite had fallen from high sky then was remelted into a plastic form prior to reach and partly cover a piece of well-rounded pebble.These evidences suggest that there was a meteoritic or cometary impact on our earth surface somewhere in the region then catapulted numbers of melted silica ejecta with vast volume of dust into the sky.The melted silica ejecta were solidified into splash-form tektites with various shapes while they were in the high sky.After that the tektites had fallen down and remelted into a plastic form prior to reach the ground surface and then solidified as a tektite deposit followed by larger-sized sediments and angular quartz fragments forming a fining upward sedimentary structure.The finer sediments were gradually settled down forming a bright reddish brown structureless sand deposit,the Yasothon soil series.This meteoritic impact event occurred at about 0.77 Ma ago as the evidence of the previous tektite radiometric dating.

How to estimate the effect of an intense meteor shower on human space activities

In the present age,the potential threat to space projects coming from some intense meteor storms has been noticed.Especially,the increasing activities of mankind in space for scientific,commercial and military purposes have led to an increase in safety-related problems about the satellites,space stations and astronauts.Several new techniques for observing meteors and meteor showers have been developed.However,how to estimate even predict the effect of an intense meteor shower should be further studied.The initial definition about a meteor storm based on visual observations with a Zenithal Hourly Rate of over one thousand seems insufficient,since it only means a storm or burst of meteors in numbers.In 2006 the author suggested a synthetical index of the potential threats about intense activities of meteors;however,it is too complex to determine several parameters.In this paper,the author suggests a Special True Number Flux Density(STNFD).Set a certain energy-limit,or a certain electric-charge-limit,and then calculate the number flux density.Through the comparison between two of the 10 strong meteor showers in recent years it is found that the important factor affecting the space flight security is not only the number of meteoroids,but also their velocities,their average energy and the population index r.Calculations show that Giacobinids,even June Bootids,should be one of the most hazardous meteor showers.

Silica-Metal Spherules in Ignimbrites of Southern Primorye,Russia

A comprehensive mineralogical-geochemical and petrological study of ignimbrites from the Yakut-Gora volcanic depression （Primorye, Far Eastern Russia） revealed a wide distribution of silica-metal spherules （＂globules＂） that are typical liquid immiscibility resultant. The metallic portion of a spherule （composition varies from low-carbon iron to cohenite） borders gas pores and is rimmed by symplectite that consists of quartz, magnetite, and silica-potassic glass. This allows us to consider that the whole formation formed through reduction of the enclosing silicate melt. Abundant evidence of high reduction states of ignimbrite melts and the presence of iron carbides suggest an H2-CH4 composition of the fluidal phase in ignimbrite magmas.

Fission-Track Age of Bobai County and Baise Basin Tektite in Guangxi

Tektite arouses great concern of the scientists in different fields, mainly because it is a synthesized material produced by impact between terrestrial material and extraterrestrial material, and the falling or forming process of tektite has never

ELEMENT GEOCHEMISTRY OF MELT AND BASEMENT ROCKS OF NUCLEAR EXPLOSION CRATER

Most terrestrial impact craters such as Ries and Lappajarvi craters contain a lot of impact melts. The common character of the impact melts includes (ⅰ) an extremely homogeneous composition, (ⅱ) the chemical component of melt indicating the properties of basement rocks and (ⅲ) the partial melts