Without concentrated ores of insoluble metals embedded into Earth's crust, human civilization would've never advanced beyond a stone-age culture. Today we have the ability to glean unconcentrated metals from rocks, soils, and oceans. The technology to do so, however, wouldn't exist without humanity's prior access to concentrated ores.
Most of the concentration of Earth's ores resulted from bacterial activity. For example, over the course of hundreds of millions (in some cases billions) of years, different species of sulfate-reducing bacteria fed on dilute soluble metal compounds, converting these compounds into insoluble forms. The decayed residues of the bacteria yielded the concentrated ores.
An international team of geologists recently elucidated another metal-concentrating mechanism unique to Earth, at least in its extent.1 This mechanism is the concentration of metals in hydrothermal solutions.
Hydrothermal fluid flow moving through a mineralized part of Earth's crust will transport dissolved metals. If a mechanism exists to precipitate out these metals in insoluble form within a confined local region for a long enough period of time, an economically mineable ore deposit will form. That is, hydrothermal fluid flow under just-right conditions can scavenge metals at a low concentration level from a large volume of rock and then concentrate those metals into a much smaller rock volume.
In their research paper, the team of geologists proposed2 a number of mechanisms known to operate within Earth's crust that could explain the precipitation. They then performed a set of experiments in which they used "laser ablation inductively coupled plasma mass spectrometry" to determine the enrichment factors for these mechanisms. They demonstrated that hydrothermal fluid flow could enrich the concentration of metals like zinc, lead, and copper by at least a factor of a thousand. They also showed that ore deposits formed by hydrothermal fluid flows at or above these concentration levels exist throughout Earth's crust.
The necessary just-right precipitation conditions needed to yield such high concentrations demand extraordinary fine-tuning. That such ore deposits are common in Earth's crust strongly suggests supernatural design. Evidently, the Creator used a variety of carefully designed mechanisms, both organic and inorganic, to concentrate and preserve for humanity's benefit a bountiful treasure of concentrated insoluble ore deposits.
Jamie J. Wilkinson et al., "Anomalously Metal-Rich Fluids Form Hydrothermal Ore Deposits," Science 323 (February 6, 2009): 764-67.
Robert J. Bodnar, "Heavy Metals or Punk Rocks?" Science 323 (February 6, 2009): 724-25.