DOI: 10.5880/fidgeo.2024.018
title: Geochemical and isotopic compositions of minerals and bulk rocks of the Chachimbiro Volcanic Complex (Northern Andes, Ecuador)

description: This dataset provides geochemical data from from the Quaternary Chachimbiro Volcanic Complex (CVC), situated in the Western Cordillera of Ecuador, Northern Andes (0.468°N, 78.287°W). 
 
The CVC is subdivided into 4 eruptive stages (CH1, CH2, CH3, CH4) ranging in age between ~400 and ~4 ka ago (Bellver-Baca et al., 2020). The CH1 stage consists of andesitic flows erupted between 405.7 ± 20.0 and 298.6 ± 32.9 ka with collapse of the pre-existing cone at the end of the effusive period (File #1). The following CH2 stage (121.75 ± 23.2 -36.08 ± 2.8 ka) consists of andesitic to dacitic domes and pyroclastic rocks which also suffered a collapse event as shown by the scar and the uprooted domes in the hillside of the edifice (File #1). The CH3 unit (36.08 ± 0.28 – 22.73 ± 0.12 ka) consists of two main andesitic to dacitic domes (Hugá and Albují: H and A, respectively, in File #1) and effusive rocks. CH4 consists of a volumetrically small rhyodacitic pyroclastic unit which was produced by a lateral blast dated at 5.5-5.8 ky ago. A younger pyroclastic episode (&lt;4.15 ka ago) has been related to the Pucará dome (Comida, 2012), but rocks of this event have not been investigated in the present study. The bulk rock and mineral data are used to reconstruct the plumbing system beneath the CVC during its ~400 ka long lifetime. Since the temporal geochemical evolution of CVC bulk rocks towards higher values of adakite-like indices (e.g., Sr/Y, La/Yb) bears strong similarities to that of magmatic systems associated with supergiant porphyry copper deposits, these data may serve to better understand how adakite-like signatures are acquired in fertile arc magmatic systems with metallogenic implications. 
 
Files included are: 
 
• 2024-018_Chiaradia-et-al_Table-1_Sample-overview: sample overview table with coordinates of and type of analyses carried out on each sample (Table #1) 
 
• 2024-018_Chiaradia-et-al_File_1_map: a geological map with location of investigated samples (File #1) 
 
• 2024-018_Chiaradia-et-al_File_2_WholeRocks: geochemical and radiogenic isotope data on bulk rocks (File #2). 
 
• 2024-018_Chiaradia-et-al_File_3_Pyroxene: contains microprobe and LA-ICP-MS major and trace element analyses of clino- and orthopyroxenes from the CVC and P-T conditions retrieved from clinopyroxene compositions (File #3) 
 
• 2024-018_Chiaradia-et-al_File_4_Amphibole: contains microprobe and LA-ICP-MS major and trace element analyses of amphiboles from the CVC and P-T-H2Omelt, fO2 conditions retrieved from amphibole compositions (File #4). 
 
• 2024-018_Chiaradia-et-al_File_5_Plagioclase: contains microprobe and LA-ICP-MS major and trace element analyses of plagioclases from the CVC (File #5). 
 
• 2024-018_Chiaradia-et-al_File_6_Equilibrium tests: reports the calculations to retrieve pressure and temperature data from clinopyroxene-melt equilibrium and clinopyroxene-only composition (File #6). 
 
• 2024-018_Chiaradia-et-al_File_7_CPX_Thermo_Barometry: reports the calculations to obtain P-T conditions from clinopyroxene-orthopyroxene equilibria in the same thin section (File #7). 
 
• 2024-018_Chiaradia-et-al_File_8_Cpx_Opx_Thermo_Barometry: reports the equilibrium tests between minerals (clinopyroxene, orthopyroxene, amphibole) and host rock compositions and the P-T values retrieved by clinopyroxene and amphibole analyses that passed the test (File #8). 
 
 
Associated RStudio Scripts are available as https://doi.org/10.5880/fidgeo.2025.010 (Chiarada, 2025).