SOME CHARACTERISTICS AND CAUSES OF CHANGES IN THE RATE OF DISCOVERY OF NEW MINERALS SINCE 1800

Abstract

ABSTRACT Construction of a discovery curve for Earth's minerals illustrates an abrupt inflection in rates of discovery and acceptance of new species that occurred in the middle of the 20th century. Prior to that time new mineral discovery is found to have accelerated at a modest pace of 0.3 species / year2. Since 1950 the rate of acceptance has accelerated at an average of 1.04 species / year2 such that the first two decades of the 21st century have been characterized by the acceptance of over 100 new minerals per year. Despite this rapid acceleration of discovery, the relative distribution among the 10 mineral classes of the Nickel-Strunz classification system of minerals identified prior to and after 1950 are nearly identical. Variation in the rates of attestation of the divisions, families, and mineral groups show distinct differences in that the maximum rates of discovery of minerals populating higher taxonomic levels occurred prior to 1950 while the attestation curve of newly recognized groups closely follows that defined by the identification of mineral species. The application of any hierarchical classification system to the mineral species is somewhat arbitrary and subject to biases or inconsistencies associated with the systematics of classification. Therefore, the discovery of new minerals is also considered within the context of the mathematically defined crystallographic space group symmetries. The space group attestation curve has a shape similar to those exhibited by the higher taxonomic levels within the Nickel-Strunz system. However, not all space groups are represented by naturally occurring minerals. Minerals discovered before and after the inflection in rates of new mineral discovery illustrate significantly different patterns of paragenesis. Nearly all of the species have been associated with one or more of 57 distinct paragenetic modes. Minerals that have long been known tend to have a higher number of paragenetic modes than those more recently discovered such that the average number of paragenetic modes is shown to have decreased linearly from 1950 to 2022. Further, the earliest known occurrence of over 80% of the currently accepted mineral species has been tabulated by the International Mineralogical Association. For species discovered prior to the inflection of 1950 a linear distribution of oldest ages is observed indicating that these minerals have earliest ages of occurrence that are uniformly distributed across the interval 0 to 4700 Ma. Conversely, approximately 70% of the species identified since 1950 have oldest known occurrences of less than 600 Ma and the age distribution of these post-1950 minerals exhibit an exponential distribution suggesting increasing efforts in new mineral discovery in tectonically active settings. Despite the differences in the pre- and post-1950 oldest age distributions, both populations exhibit similar temporal excursions in rates of new mineral creation that likely reflect substantial changes in Earth system processes responsible for new mineral formation.