History of rice

Discussion in 'History' started by garry420, Feb 7, 2016.

  1. garry420

    garry420 Well-Known Member



    “Rice is an integral part of many cultures folklore. In Myanmar, the Kachins were sent forth from the center of the Earth with rice seeds and were directed to a country where life would be perfect and rice would grow well. In Bali, Lord Vishnu caused the Earth to give birth to rice and the God Indra taught people how to raise it. And in China rice is the gift of animals. Legend says after a disastrous flooding all plants had been destroyed and no food was available. One day a dog ran through the fields to the people with rice seeds hanging from his tail. The people planted the seeds, rice grew and hunger disappeared. All of these stories and many others have rice as their foundation and for generations people have believed these lores of Rice. ” (Thomas L. Rost, 1997 http://www-plb.ucdavis.edu/labs/rost/Rice/introduction/intro.html )

    Mekong delta



    Transporting rice husks on the Mekong river


    Mekong river, Laos


    Rainfed rice cultivation in Soc Trang on Mekong delta

    Compare with the figure on the left, the satellite image on the right shows progression of the cultivation in stages. In the rainfed single-cropped area is now flooded and appears dark. The wet direct seeded area now appears in mixture of dark and brighter red. The rice crops in the dry direct seeded areas around Soc Trang is in the end of reproductive stage and appears in reddish gray in the image. (Courtesy: S.C. Liew et al., 1998, Rice crops moitoring in the Mekong river delta using combined ERS and RADARSAT synthetic aperture radar, IEEE).


    Mekong river, Laos-Cambodia border


    Satellite Images ~ Rivers and Deltas ~ Mekong (flooding)


    Flooding usually occurs in the lower Mekong river between Jun and Dec every year. The first image shows the Mekong river during the dry season while subsequent images depict the extent of flooding during the wet season.

    Mar 2002 (SPOT 2)

    Aug 2002 (SPOT 4)

    Sep 2003 (SPOT 4)

    Sep 2004 (SPOT 2)

    All satellite images shown have undergone jpg compression for display purposes, they do not represent the true resolution of the original images. All satellite images are copyrighted :
    © CNES 1995-2005

  2. garry420

    garry420 Well-Known Member

    Figure 3. A global view of India’s collision with Asia (modified from Molnar 1986)

    By the mid 1970s, the theory that the Himalayas were produced by a collision between India and Asia was becoming widely accepted (Figure 3), but it raised major questions regarding the displaced mass of Asian crust. Since about 50 mya, it appeared that India had penetrated at least 2000 km into Asia, but it was not clear that the mass of the Himalayas and the thickened crust beneath the Tibetan Plateau were sufficient to account for the entire mass of displaced Asian crust. Using satellite images and seismic analysis, Molnar and Tapponnier (1975) recognized major east-trending, left-lateral strike-slip faults emanating from Tibet. These faults sliced the areas east and southeast of Tibet, implying that crustal mass north of the Himalayas was shifting eastward and southeastward as India moved north (Figure 4).

    Figure 4. Major crustal blocks, age of uplift, and direction of motion in western China (adapted from Tapponier et al. 2001).

    Molnar and Tapponnier hypothesized that the Yunnan Plateau and the Shan-Thai Plateau are now much further southeast than they were before the collision (Figure 5).

    Figure 5. Clay model illustrating the relationship between India’s northward motion and east-southeast extrusion of southeast Asia (modified from Tapponnier et al.1982).
    We decided that the Mekong River Canyon in western Yunnan was the best region for examining faults to determine whether large blocks of southeast Asian crust were being extruded

    southward towards Indochina. The river crosses several faults in a canyon two miles deep in the stretch where it changes direction from south to southeast (Figure 6). We hoped to investigate the nature of these faults to determine their relationship to the development of the Himalayas and the uplift of the Tibetan Plateau.

    Figure 6. Satellite view of the Mekong and Yangbi drainages in western Yunnan (Landsat photo).

    To achieve this objective, our plan was to determine the sense of shear in mylonites, to sample shear zones for radiometric dating, and to sample overlying Triassic red beds to measure paleomagnetic latitude and orientation. Mylonites are fault rocks, which are cohesive, characterized by a well-developed schistosity resulting from tectonic reduction of grain size, and commonly contain rounded porphyroclasts and lithic fragments similar in composition to the matrix minerals. Fine scale layering and an associated mineral or stretching lineation are commonly present. Brittle deformation of some minerals may be present, but deformation is commonly by crystalplasticity (Brodie et al. 2004).

    Figure 7. Geologic map of western Yunnan.

    A related objective was to take paleontological samples in hopes of justifying further research on patterns of environmental change as the rising Himalayas modified the climate of this area. Will was one of the oarsmen and the only paleontologist on the team.

    In southwestern Yunnan, the Mekong River weaves back and forth across the contact between metamorphic rock units and Mesozoic sedimentary strata (Figure 7).


    According to Chinese geologists, the metamorphic rocks are of amphibolite grade, and therefore temperatures in them have exceeded 450°C. More importantly, the metamorphic rocks are strongly sheared, with a near vertical northwest-trending foliation and subhorizontal lineation characteristic of rocks that have experienced high shear. Neither the sense of shear nor their age was known. On Chinese maps, the sedimentary rocks were shown as Jurassic and Cretaceous shallow marine deposits in fault contact with the underlying metamorphic rocks. Determining the nature of this contact was an important part of our research proposal.

    In summary, we planned to examine in detail the deformation and rotation of rocks exposed along the Mekong River in western Yunnan to characterize the age, style, intensity, distribution, and sense of crustal shearing induced by the collision and penetration of India into Asia. We hoped to constrain the extent and the timing of extrusion of parts of Indochina from an initially more northwesterly position and to place bounds on the amount and distribution of shearing in western Yunnan due to India sliding northward past Yunnan. We believed that a detailed study of one key area was a better approach than a superficial examination of a large area.

    The stretch of Mekong that we planned to run appeared to offer a wide range of possible approaches to studying this deformation. Knowledge gained from this area would be fundamental to understanding areas of more complex deformation in northern Yunnan, western Sichuan, Tibet, and Qinghai. We hoped to expand our collaborative research program to these regions, concentrating on areas where our collective expertise could have been used to maximize the results of our research. Although Will’s scientific background and interest were generally limited to the paleontological aspects of this expedition, his role as an experienced whitewater river guide who could read, write, and speak Mandarin was critical to the success of the expedition.


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