Dear Mr. Bhowmick,

Sodium is contained in the most widespread silicate in the crust plagioclase. After decomposition by chemical weathering the albitic part of the s.s.s. contributes the majority of Na to the seawater. Chlorine may have derived from subaerial and subaquatic exhalations and the decomposition of micaceous sheetsilicates which also are subjected to chemical weathering.

H.G.Dill

Dear collaeage : by chemical weathering: the solubility of the elements. The charge (e) and the radius (r) of the ions are used to estimate their degree of solubility as expressed by the Goldschmidt potential (e/r):

Thank for your question, i am geologist and will be answer from geology, Sodium and Chloride belonging to chemical reaction and chemical weathering, and we have different materials in nature like soluble and non soluble, soluble like carbonate, salts, lime when water infiltrated between lithology of land and its leached with water and transported to the oceans by rivers and runoff.

Hello Sumit,

As a highly incompatible volatile element, the vast bulk of earth's primordial chlorine would have partitioned into the early-formed magma ocean and degassed along with water vapour into an early steam atmosphere and ocean. So the short answer to where the chloride has come from is that it has always been present in seawater as a result of degassing, likely at similar concentrations to today, since the formation of the oceans >4Ga ago. This, of course, precludes weathering of the continents as an ultimate source.

HCL from volcanic emissions and mid-ocean ridges is the principal way "new" chloride is added to the oceans. Even this, however, may largely be derived from seawater chloride recycled by subduction zone volcanism or ingassed into the upper mantle more generally.

Hope this helps.

Dear Mr. Howes,

when did ocean water start forming NaCl from the chlorine and where did the Na come from during which event ?

The mantle and the universe can be seen as the "deus ex machina" for all chemical compounds and elements.

H.G.Dill

Take a look to my Paper on Geological History of Earth Atmosphere. Available in ResearchGate.com

If you are asking about the original source of these two ions, I think for the Na it's easy to explain because it's included within the mineralogical composition of igneous rock, but for the Cl the most possible source is the volcanic submarune plumes because the fumesof the new erupted plumes contains chlorine compounds

I repeat it once more:

Sodium is contained in the most widespread silicate in the crust plagioclase. After decomposition by chemical weathering the albitic part of the s.s.s. contributes the majority of Na to the seawater. Chlorine may have derived from subaerial and subaquatic exhalations and the decomposition of micaceous sheetsilicates which also are subjected to chemical weathering. H.G.Dill

Dear Harald

I concur completely with your comments regarding sodium.

However, I am puzzled why you assert that weathering of continental crust has been an important contributer to the inventory of seawater chlorine. I don't disagree with mica and amphibole weathering as the principal means of extracting structurally-bound chlorine in igneous and orthometamorphic rocks from the upper continental crust to to the oceans. But it is easy to show with simple mass balance calculations that it cannot be the main, or even a significant, contributer to ocean chlorinity. Secondly, if you look at the chlorine flux from present-day continental runoff, it turns out that the bulk of non-anthropogenic chlorine shed into the oceans today comes simply from recycling of seawater chlorine via oceanic aerosols.

That leaves, as you say, volcanic degassing (HCl). Because the geochemistry of the ocean - crust system is essentially in a steady state, and has probably been so for several times longer than the longest mean residence times of seawater constituents (including chorine), it is difficult not to conclude that the bulk of volcanically degassed chlorine today must be recycled from past ingassing of seawater-derived chlorine into to the mantle via subduction (for example, via subduction of partially-serpentinised oceanic crust), followed by convective mantle mixing, and that these ingassing and outgassing fluxes are in balance. If there is a contribution to seawater chlorinity from ongoing primordial chlorine degassing, it must be small.

Many workers have concluded from this that today's seawater chlorine inventory must have its origins in the (partial) degassing of the silicate earth extremely early in earth history, consistent with the evidence from atmospheric rare gas systematics. Deeper parts of the earth's mantle may contain undegassed primordial chlorine, but the putative contribution of this component to seawater chlorinity over time is presumably small, constrained as it is by the 3He/4He systematics of OIB.

Dear Sumit Bhowmick,

You have interesting questions that make people think of our origin.

You had excellent answers so far. In short, sodium comes from weathering (of plagioclase, etc), chlorine from volcanoes.

K comes from weathering of orthoclase. Plagioclase is more abundant than orthoclase, thus maybe there was less in the seawater and the body fluids that were incorporated into the first living forms (our ancestors).

It will be came from continental to ocean by leaching

Dear All

I can go along with the Cl to be orginally delivered from exhalations as I stated in my first answers. A lot of Cl is contained not only in phyllosilicates but in many other minerals which also contain F- and OH-, both of which can be replaced by Cl-. A nice example is the phosphate group. Fluorine apatite is typical of crustal derivation and contained in granites and pegmatites, Cl apatite is typical of basic magmatic rocks (see Cl apatite in the Henry Ore Body at Kiruna Fe ore district) and OH- and CO2 apatite is typical of sediments. This mineral group shows how step-by-step the chlorine is released through geological time from the original source and supplied to the aquatic system. That is why I do not exclude the mantle as a primary source but I try and avoid to ignore the intermediate stages which are involved. I hope this may explain my approach to this question.

With kind regards

H.G.Dill