Sulphur mobility and sulphur‐mineral precipitation during early Miocene‐Recent uplift and sedimentation in Central Otago, New Zealand

Abstract

Since the late Oligocene -early Miocene, three distinct uplift events have resulted in widespread sediment deposition in Central Otago, South Island, New Zealand.

Geological controls on the sulphur content of coal seams in the Northumberland Coalfield, Northeast England

“…In freshwater drainage systems, sulphate may be derived from source rock weathering, which provides the major source, and marine sulphate from seaspray which produces a flux of aerosol sulphate into the atmosphere (Granat et al, 1976;Youngsen, 1995). However, marine sulphate contributes much less than total river water sulphate (Hunt, 1987), especially given the distance from the coastline in the Northumberland basin.…”

“…Sulphur may be readily oxidised and leached from sulphur-bearing source rocks and carried into the basin in solution mainly as terrestrial sulphate in the drainage system. Significant sulphate mobility occurs particularly when sulphur-bearing source rocks undergo uplift and erosion (Youngsen, 1995). Although local intrabasinal source rocks, such as Farne (Fig.…”

“…7). Thus, sulphate-rich waters derived from these source areas could have enhanced the normally low-sulphate content of terrestrial waters (11.2 ppm, Youngsen, 1995), and on entering the basin contribute to the groundwater system, which is typically richer in sulphate than river water (Youngsen, 1995). The presence of syngenetic pyrite in the coal seams suggests that sulphate-and ferrous-enriched groundwater and overbank floodwaters infiltrating the peat mire, precipitated sulphide, and that the pH of the mire was sufficiently high to promote sulphate-reducing bacterial activity (Shao et al, 2003).…”

“…The presence of epigenetic veins and cleat-filling pyrite (Love et al, 1983;White et al, 1994;Bouška et al, 1997;Gayer et al, 1999) suggests that some sulphur may have been added to the coal following deposition and cessation of organic peat reactivity (Hunt, 1987;Youngsen, 1995). In the UK, Westphalian Coal Measures cleat formation is thought to be primarily controlled by tectonism following uplift and release of overburden pressure (Rippon, 1996).…”

Initial sedimentation and subsequent diagenesis in the Eastern Southland Lignite Basin, southern New Zealand

“…Hence, chemical mobility may be responsible for redistribution of pyrite into some basal sands in the Mataura coalfield cores examined in this study. This localised remobilisation of marine-related sedimentary pyrite is different from pyrite impregnation of non-marine sediments that occurs during chemical reduction of shallow groundwater that contains dissolved sulphate from marine aerosols (Youngson 1995). Pyrite deposited by the latter phenomenon can be irregularly present within shallow sediments in the ESLB (Clough & Craw 1989;Falconer et al 2006;Craw et al 2008).…”