Dust – A geology-orientated attempt to reappraise the natural components, amounts, inputs to sediment, and importance for correlation purposes

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Abstract

The paper deals with the recent and present-day natural components of the dust inputs to sediments, and aims to attract the attention of geologists to atmospherically mediated teleconnections among basins across the globe. Similar components as today can also be expected to exist in the pre-human history of the Earth, with capability to affect the quantity and quality of non-carbonate phases in limestones. However, a significant part of atmospheric dust sedimentation is not sufficiently covered by standard measurements. Owing to air quality regulations, most of the present research is conducted to understand the emissions and atmospheric load of PM₁₀, and a lesser number of studies map the possible transport of coarser natural particulate matter over the large distances. With respect to the studied particle sizes and methods of their determination, the present-day aerosol science and geological approach, focused on measured sedimentation or input to sediment, show practically no overlap. We report the first evidence (or at least a well-reasoned hypothesis) that the low numbers of frequently occurring large particles, e.g. with 50-m d_e or larger, must always represent a substantial mass added to mineral dust budgets. These rare and bulky particles are either transported with the super-storm dust plumes in the troposphere, or with the jet streams near the tropopause. From the geological point of view, it is important to consider all sizes of mineral-lithic particles or grains, particularly from the silt to fine-sand sizes (i.e., 4–250 m). In atmospheric physics, only the total suspended particulates (TSP) are a partial and often unreliable counterpart. This subject is especially worth of exploring although the emerging discipline, combining the estimates of the total burden of atmosphere by every classes of the natural solid particles and their measurable ‘final sedimentary inputs’, is still encumbered with much imprecision, and the reported results are more concerned with the principles and rough estimates than all variants of calculations. Classifying the components by their sources, this attempt suggests that the ideal mean airborne inputs to the sediments on the present-day Earth are approximately as follows (g/m²/yr): terrestrial weathering ≈ 3.3; volcanic ash ≈ 0.3; biotic ≈ 0.5; cosmogenic ≈ 0.0002; wildfires ≈ 0.3; solids with ultra fine secondary aerosols ≈ 0.02, giving a total of ≈ 4.4. Therefore, a mean (ideal) input of the natural dust to the present (and possibly also Holocene) sediments of about 4–5 g/m²/yr should be considered. Naturally, the real inputs vary geographically to a large extent (± a few orders of magnitude).

Om dit artikel te citeren:

Over : Jindrich HLADIL

Over : Petr CEJCHAN

Over : Ondřej BÁBEK

Over : Leona KOPTIKOVA

Over : Tomas NAVRATIL

Over : Petra KUBINOVA