Dust flux, Vostok ice core

Dust flux, Vostok ice core
Two dimensional phase space reconstruction of dust flux from the Vostok core over the period 186-4 ka using the time derivative method. Dust flux on the x-axis, rate of change is on the y-axis. From Gipp (2001).

Tuesday, October 31, 2017

Huge development in Zhengzhou

The second subway line for Zhengzhou, running from the north end of the city to the airport was completed last year. I took it out to airport city a couple of weeks ago.

Along the way, there is an enormous new real estate development--it must have run about 2 km along the track, almost entirely filling in what used to be a forested area between Zhengzhou and what used to be a separate town (Hua'nancheng). Unfortunately, the subway is enclosed in tube with these horizontal lines, obscuring the imagery.

And here's some video to give you a sense of scale.

Monday, October 30, 2017

Loess in west Zhengzhou

I decided to go somewhere a little different in the city, so on Golden Week, I took the subway out to the civic centre.

Correction: I took the subway to the station that was called Civic Centre. It seemed reasonable at the time to assume the civic centre was there. Since it was a national holiday, I thought it possible that there would be some kind of public event in the space.

The subway system was built very rapidly over the past few years, and is in the midst of an enormous expansion. The subway appears to be built to support the growth model designed by the local urban planners, so that there are portions of it built through areas that are as yet undeveloped.

Such as the 'Civic Centre' station.

Inside the station was a map of the surrounding area. There were three exits, and the third exit appeared (from the map) to be near an amphitheatre, with a winding path through a forest leading to the main road. This was the exit I chose. But when I reached the surface, all that was there was a chewed up field, with a couple of collapsing buildings with a farming family squatting inside. Nearby, a dirt track led to a dilapidated village.

In the distance were several high-rise apartments under construction. So my conclusion is that this area will host the civic centre one day. But not quite yet.
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South and a little east of the civic centre is a broad ravine with steep sides. Near the subway line there is no easy access, but as one approaches Zhongyuan Road, the ravine becomes a park, and there are a number of easy access points. This park is called Xiliuhugongyuan, or West Six Lake Park (it isn't clear to me if this means there are six lakes, or it refers to lake number six).


Zhongyuan Bridge crossing the ravine

Given the density of population and commerce, Zhongyuan Rd. looks like a better choice for the subway than where it actually is. But then it would have to cross this bridge, which isn't strong enough.

What struck me is the thick accumulations of loess that are exposed at the sides of the park.

The cliffs range from about 5-10 m high, and consist of nearly vertical, fractured faces of silt. Presumably, they resulted from fracturing and successive block failures from the loess faces

When the loess faces collapse, they break into blocks, which themselves 
may further break down over time.

Henan province mainly lies within the great loess plain of China, where loess covers over 630 000 sq km of central China. Loess is composed of windblown silt particles in central China, but is coarser in the west, where it consists of windblown sand. In places along Huang He, the loess terraces rise above the river terrace level by up to 100 m. So the terraces in western Zhengzhou are not spectacular, but they are the only place within the city where I have seen them.


Fractures in the unconsolidated loess in Xiliuhugongyuan. 

Loess tends to be occur in dry climates, as moisture encourages plant growth which will bind the sediment together and prevent it from being transported by wind. Central China is fairly dry most of the year, with annual evaporation exceeding precipitation (Derbyshire, 1998). The majority of rain falls from July to September (it lasted well into October this year), and up to 40% of annual rainfall can happen in one day (which I can attest to, having experienced such days twice). 

Sunday, October 15, 2017

Ancient gold in Henan

This post revisits some of the artifacts on display at the Henan Provincial museum; which is presently a shadow of itself, with the main building having been under renovations for at least the last two years.

Only one out-building is open, with displays of a fraction of the museum's artifacts, primarily showing cultural development in area influenced by Huang He. This is the oldest part of China.

Gold belt from the western Zhou dynasty, ca. 1000 BCE

First model of an Imperial Star Destroyer, for the movie, The Emperor rises in Guo State.

Gold and jewellery of the Ming dynasty

Of course, this is only a small fraction of what used to be on display.