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Terrestrial Geochemistry

Taiwan

Landslides, a common feature of Taiwan's rugged topography, contribute extensively to Taiwan's rapid erosion rates.

Trisuli

Sampling the Trisuli River, central Nepal, April 2002

Tawian

Dr Neils Hovius (left) Professor Mike Bickle and Dr Josh West (right), filtering waters from a roadside borehole in Taiwan.

srcanaca gam

Figure 1

srca cana deopryag

(C) Modelling mixing relations in Sr-Ca-Na space.

sil mary

Seasonal variations in the fraction Ca and Mg derived from silicate (Tipper et al., 2006a)

new 4 isot vectors

Figure 2:

myanmar2

Farmers in the upper Salween Valley, Myanmar

myanmar1

Mike Bickle sampling waters from the Salween River in Myanmar

ganges flood plain

Ganges flood plain

eros weath

Silicate chemical weathering rate versus physical erosion rate. A key observation is that in catchments with low erosion rates, chemical weathering is nearly complete (weathering rates in such catchments give a linear relationship with erosion rates) and chemical weathering rates in such ‘transport limited’ catchments do not respond to changes in climate

degassing

CO2 produced through metamorphic decarbonation and oxidation of organic matter (1) exsolves from metamorphic fluids due to decompression and temperature loss (2). Metamorphic CO2 dissolves in meteoric groundwaters (3). Degassing near the surface (4) drives d13C DIC to values in excess of +13 permil.

bahundanda

Bahundanda hot spring on the Main Central Thrust, in the Marsyandi Valley, central Nepal. Waters are heated by the elevated geothermal gradient, and mix with deep-sourced carbon dioxide before degassing at the surface.

annapurna

The Marsyandi valley north of the Annapurna range where the river flows through the Tibetan Sedimentary Series on the southern margin of the Tibetan plateau. Despite, or perhaps because of, the cold and arid climate we estimate that between 65 and 80% of dissolved Ca is precipitated as secondary calcite within the catchment.

alaknanda map view

(A) Geological map of the Alaknanda and Bhagirathi valleys showing the geologically-restricted catchments used for input modelling. (B) The Alaknanda River where it emerges from the High Himalayan Crystalline Series across the Main Central Thrust. Note the ~6 km topographic difference between the river bed at ~1000 m and Nanda Devi at 7817 m, only 30 km away.

3d

(D) Projection into Sr/Ca to Ca/Na space. Note fit to two-component mixing and extrapolated high Sr/Ca ratios of silicate and carbonate end-members.

amygeotimes

Pillow lavas, Geotimes locality, Semail Ophiolite, Oman

sheeted-dykes

Sheeted dykes in the Semail ophiolite, Oman

plagio-dyke

Plagiogranite with xenoliths of earlier dyke generation cut by epidotised later mafic dyke in hydrothermal 'reaction zone' near top of gabbros. Semail ophiolite, Oman

epdi-dykes

Two generations of sheeted dykes both strongly epidotised. Earlier generation rotated to ~ 30° dipping screens between steeply dipping later generation. Wadi Rajmi, Semail ophiolite, Oman

pillows_wadi_amy

Pillows surrounded by epidosite.

oman6

Cu and Fe sulphides within epidosite sampled from pillow outcrop figured to left

epidosite_zones

Dark epidosite zones mapped within plagiogranite, Wadi Rajmi, Semail ophiolite, Oman

epidosite-zones-wr

Sketch-map of the previous field locality showing higher, ~ 0.705, 87Sr/86Sr ratios of epidosite zones (green) and late phorphyritic dyke (grey) compared with ~ 0.704 values in plagiogranite host rock

sulphide_pit

Mined-out massive sulphide pit in lavas, Semail ophiolite, Oman

carson-plant

Proposed Carson, CA, carbon sequestration plant. Image courtesy of BP and Edison Mission Group

sleipner

Seismic reflection profiles of the Sleipner carbon storage site, North Sea, in 1994, 1999, 2001 and 2002. The 1994 pre-injection profile shows the base and top of the Utsira Sand but little detail within the reservoir. The subsequent post-injection profiles show bright reflections where carbon dioxide is ponding under thin mudstones.

crystal-geyser

Crystal Geyser, Green River, Utah. The geyser, charged with CO2, erupts daily between 8 to 17 hours.

chaffinranch

Chaffin Ranch spring erupting. Green River, Utah

bigbubbling

Big Bubbling spring. Green River, Utah