Stratigraphic columns for the Cretaceous-lower Quaternary sediments of north-west Nelson and the West Coast, South Island

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Wellman, H.W.; Beck, A.C.; Kear, D.; Suggate, R.P.; Grindley, G.W. 1981 Stratigraphic columns for the Cretaceous-lower Quaternary sediments of north-west Nelson and the West Coast, South Island. Lower Hutt: New Zealand Geological Survey. Report NZGS 63 102 p.

Abstract: Most of the stratigraphic columns presented in this report were prepared in 1950 by H.W. Wellman and G.W. Grindley, as parts of manuscripts by Wellman covering the Cretaceous to lower Quaternary geology of NZMS 1 sheets S1-3, 7, 8, 12, 17-18, 23-24, 30-31, 37, 44 and 51. The work was not published, but copies were held in the Library of the NZ Geological Survey at Lower Hutt. The columns were based almost entirely on field work by Wellman, accompanied by various geologists at various times. Much of the basic compilation of map and fossil locality data, necessary for estimation of stratigraphic thicknesses, was carried out by Grindley. At about the same time, work in the Murchison and Reefton areas, mainly by R.P. Suggate, led to his preparing most of the stratigraphic columns for sheets S25, 32, 38 and 39. Dr Wellman was responsible for devising the format of the columns, which are presented here as they were originally prepared. The ''adopted age'' assigned at the time of preparing each column is retained. The stages of Finlay and Marwick (1947) are used, determinations being mainly by J. Marwick, C.A. Fleming, N. de B. Hornibrook and the late H.J. Finlay. Few changes have been necessary as a result of the re-examination in recent years, the main ones being noted in a short section preceding the columns. The columns were prepared before the recent advances in age assignments from palynology, so that Upper Cretaceous and Lower Tertiary non-marine rocks are not given int terms of stages. Instead they are assigned to ''Lower Coal Measures'' (LCM) which include the Paparoa and Pakawau Groups of coal measures, and the Middle Coal Measures (MCM), which include the Brunner beds and other quartzose coal measures. In contrast, the ''Upper Coal Measures'', interbedded with middle Tertiary rocks or underlying the Moutere and Old Man Gravels that close the sequence in many areas, are assigned to Tertiary and Lower Quaternary stages. Wellman and Grindley interpreted the results of sampling the critical sections detailed in most of these columns with the previous regional geological mapping to produce the series of maps and accompanying texts. Although not published in the form in which they were prepared, the maps provided the essential basis for depicting the Cretaceous and Cenozoic rocks in the 1:250,000 series, mainly sheets 13 and 15.