Journal of the Royal Society of Western Australia, 75 (1), March 1992 Stratification and disconformities in yellow sands of the Stratification and disconformities in yellow sands of the Bassendean and Spearwood Dunes, Swan Coastal Plain, Bassendean and Spearwood Dunes, Swan Coastal Plain, South-western Australia: discussion. South-western Australia: reply. A recent article in the Journal of the Royal Society of We welcome the opportunity provided by Pearce's letter Western Australia (Classford & Semeniuk 1990) provided to discuss aspects of our recent paper (Glassford & Seme¬ evidence for arid phase transport of Bassendean and niuk 1990). Spearwood Dunes of the Swan Coastal Plain. While agree¬ ing with many of the conclusions, I note on page 77 a report In relation to our statement that generally there has been °1 no previous work on stratification of the deposits, on no previous work on stratification in yellow sands, we Page 78 that the age is mainly mid-Pleistocene, and on page emphasise that our comments concern primary sedimen¬ 7° that wind directions were mainly from the east. Various tary statification in the yellow sands, and not the gross overprint' features are listed on'page 90 without any layering which locally is evident. The gross layering is due mention of human activities, yet the latter are well known to either secondary alteration (pedogenic/diagenetic), or on the Plain, sometimes from deposits one or two metres the superimposition of successive units which exhibit these secondary alteration features. 1981) Wit^ Holocene carbon dates (for example, Pearce Human activities are suggested by Pearce as an agent for alteration of yellow sand. While we accept in principle that Some of these locations indicate deflation, but others anthropogenic activities can alter and perturbate yellow certainly show accumulation of aeolian sediments, and the sand in the younger parts of the sequence, we did not question remains, were they localised and related to unequivocally detect the products of any such activity at aisturbance of occupation, or were they part of a wider nobility of upper layers of soil during the Holocene? our study sites. Our study concentrated on the description of primary stratification features in deep sequences of the Further, although Walyunga is not on the coastal plain it yellow sands, as a basis for interpreting the primary oes contain a large dune 5.1 m deep formed by easterly sedimentary origin of such sequences. We described the |nds, where the upper 1.9 m contains stratified sandy soil types of alteration in these sands only as a basis for (ptn occupation debris spanning most of the Holocene interpreting overprint features, to enable us to peer earce 1978). It even shows good evidence of a mid- through the alteration effects. In our study the alteration °locene hiatus possibility linked to aridity. features were overwhelmingly biological such as humifica¬ tion, or bioturbation by vegetation and fauna (e.g., termi- Finally the Upper Swan site has alluvial deposits but it is tarium structures), and chemical, such as bleaching and D se to Bassendean dunes and its dated soil profiles cementation. In regards to anthropogenic alteration effects, 1983)' S°me clueS to Iate Pleistocene changes (Pearce we also envisage that it would be more probable to detect such effects in areas where human occupation may have u Sucb studies and others published (Hallam 1987) and been more likely, that is, near river courses such as at Published show that there was intermittent human Walyunga, or near estuaries such as at Mosman, where to shi Parts tbe Swan Coastal Plain, and such studies date they have been mostly found. Our study sites, . juid contribute towards interpretation and understand- however, were well away from such localities. It is appar¬ of its development. ent that the bulk of the yellow sand pre-dates 10,000 years, and even c. 50,000 years, the approximate time that humans ^ H Pearce are believed to have arrived in Australia, so we do not ft! b>avies Crescent, Kalamunda, WA 6076 expect that there should be evidence of human alteration in ece,Ved 18 August 1990 the deeper sequences of the yellow sand. These deeper sequences form the major bulk of the yellow sands. Now for the matter of the the age of the yellow sand sequences. We have no problem in accepting Holocene u References ages that have been obtained from radiocarbon dating of c~lrri B J 1987 Coastal does not mean littoral. Australian charcoal from the upper parts of the yellow sand se¬ Archaeology 25:10-29. quences. However, such dates must be viewed as chroni¬ •s ford DK & Semeniuk V 1990 Stratification and disconformi¬ cling events only in the upper, near-surface parts of the ties in yellow sands of the Bassendean and Spearwood yellow sand sequences. This surficial zone is also the only Dunes, Swan Coastal Plain, South-western Australia. place in the yellow sand sequences where the radiocarbon Journal of the Royal Society of Western Australia 72:75-93. material is located. These radiocarbon dates therefore should not be construed or extended to infer ages for the tlfCe F H 1978 Changes in artifact assemblages during the last «'000 years at Walyunga, Western Australia. Journal of the entire sequence of the yellow sand thoughout all parts of P K°yal Society of Western Australia 61:1-10. the Swan Coastal Plain. For instance, it it is possible that the sand overlying the uppermost disconformity at Site 7 (Fig. Cl R H 1981 Artifact usage and sea level changes. The Artifact 3) was emplaced in the Holocene. But such a date should 6:30-33. t>earc not be extrapolated throughout the whole sequence as the Ce * H 1983 Archaeology by system and chance. In: Archaeol¬ age of all the underlying sands and disconformities. ogy at ANZAAS 1983 (ed M Smith) Western Australian Evidence of other authors also shows that yellow sand Museum, Perth, 350-358. underlies Tamala Limestone. Thus, these yellow sands 1 °S308M Western Australia, 75 (1), March 1992 Journal of the Royal Society of explain some of the ages and sequences evident in yellow predate the limestone, and hence ^ sands near the coast. cene. A Holocene age for the IsoUted D K Glassford1 and V Semeniuk2 yellow sand sequence, or a H b tQ derjve an age outlier of yellow sand, should n , vvhere< We envisage l33 Rockett Way, Bullcreek, WA 6149, and 221 Glenmere Road, for the entire yellow sand sequen t .g phases Warwick, WA 6024 that the upper surficial partof e > eU° - < ^ Ho,ocene Received 23 December 1991 of activity and mobility dunng th y this Reference and during these times, human occupat on sites m Glassford D K & Semeniuk V 1990 Stratification and disconformities in region coutd be expected to be boned A the yellow sands of the Bassendean and Spearwood Dunes, Swan Coastal Plain, South-western Australia. Journal of the Royal Society of Western Australia preparing a paper (Semeniuk & / as j^is will remobilisation of yellow sands in coastal areas, inis wi 72:75-93. Recent Advances in Science in Western Australia Life Sciences Earth Sciences Banksia cuneata is the rarest of the 76 Banksia species, with Much of the Fortescue Group in the Hamersley Basin is only 350 plants surviving. The most limiting factor in older (2765-2687 Ma)^han the regeneration after fire-induced seed release was survival terrane according to N T Arndt or me m The over the first summer (less than 0.1% of seedlings in this fiir Chemie Germany, and Australian c°,^aSuc"' study by Lamont and colleagues of the Curtin University of Platform cover was being deposited on the Pilbara granite- Technology), and survival was greatly improved by regu¬ SeensiSne temne whife tile Yilgarn granite-greenstone lar watering or transplanting to moister sites: Lamont B B, Connell S W & Bergl S M 1991 Seed bank and population dynamics of Banksia cuneata: the role of time, fire, and moisture. Botanical Gazette 153:114-122. of Earth Sciences 38:261-281. The term serotiny is suggested by B B Lamont at Curtin A useful synthesis and interpretation of seafloor spread¬ University of Technology as the most appropriate term for ing around Australia from 160 Ma to present, based on plants that retain some of their seeds for more than a year changes in plate geometry, is provided by J Veeveirs and - this phenomenon is more widespread among shrubs and colleagues of the Macquane University School of Earth trees of south-western Australia than anywhere else in the Sciences* world: Veevers I J Powell C McA & Roots S R 1991 Review of seafloor Spreading around Australia. I Synthesis of the patterns of spreadmg. Lamont B B 1991 Canopy seed storage and release - what's in a name? Australian Journal of Earth Sciences 38.373-389. Oikos 60:266-268. Precambrian geological history of the Hamersley basin is Lupin yields were improved by 10-90% when super¬ interpreted in terms of plate tectonics by J M Tyler of the phosphate was banded 5-8 cm below the seed compared Geological Survey of WA. After development of the with banding with the seed, and was decreased by 30-60% Fortescue and Hamersley Groups (2750-2300 Ma), a con¬ by topdressing P, according to R J Jarvis and M D A Bolland vergent phase began as a result of a collision between the of the WA Department of Agriculture. Banding improved Pilbara and Yilgarn Cratons resulting in the Capricorn root interception and uptake of P: Orogeny (2200-1600 Ma): Tyler I M 1991 The geology of the Sylvania Inlier and the southeast Jarvis R J & Bolland M D A 1991 Lupin grain yields and fertiliser Hamersley Basin. Western Australia Geological Survey, Bulletin 138. effectiveness are increased by banding superphosphate below the seed. Australian Journal of Experimental Agriculture 31:357-366. Detailed biostratigraphy has been used by J Backhouse of the Geological Survey of WA to correlate the coal seams in the Collie Basin and to compare them with the Karoo Basin in South Africa, demonstrating the value of pollen analysis Note from the Hon Editor: Members and non-members of in predicting the age of coal seams: the Royal Society of Western Australia are encouraged to Backhouse J 1991 Permian palynostratigraphy of the Collie Basin, submit Letters to the Editor and contributions to Recent Western Australia. Review of Palaeobotany and Palynology 67:237- Advances in Science in Western Australia. For the latter, 314. please provide short (2-3 sentence) summaries of recent Two stages are recognised in the evolution of the significant papers by Western Australian scientists or southern transform margin of the Exmouth Plateau - rifting others writing about Western Australia, together with a and shearing, followed by drifting with igneous intrusion copy of the title, abstract and authors7 names and ad¬ and undcrplating - according to ) M Lorenzo of the dresses, to the Hon Editor or a member of the Publications Lamont-Doherty Geological Observatory, New York, and Committee: Dr S D Hopper (Life Sciences), Dr A E colleagues at the Bureau of Mineral Resources, Canberra: Cockbain (Earth Sciences), and Assoc Prof J Webb (Physical Lorenzo J M, Mutter J C, Larson R L et at. 1991 Development of the Sciences). Final choice of articles is at the discretion of the continent-ocean transform boundary of the southern Exmouth Pla¬ Hon Editor. teau. Geology 19:843-846. 2