Page 4 - Demo

2074 | Geof%u00edsica Internacional (2026) 65-2of the Oligocene. It consists of a fanglomerate with clasts of shale, limestone, and sandstone (Mora, 1998; Mart%u00ednez Flores & Ortega Gamboa, 2009), with a base covered by fossiliferous limestone. Additionally, there are volcanic rock lenses, such as tuffs near the upper section (Simons & Mapes, 1956). The preceding sequence, up to the Oligocene, is covered by the Las Espinas Formation, distinguished by lavas, tuff deposits, and minor agglomerations, predominantly of andesitic and basaltic composition (Simons & Mapes, 1956).Nonetheless, Paleocene intrusive bodies are post- tectonic, as they intrude Laramide structures. Their ages range from 50 to 40 million years (Carrillo-Mart%u00ednez & Suter, 1982; Fitz-D%u00edaz et al., 2012), with varying compositions, ranging from granodiorite to diorite to monzonite to monzogabbro.QuaternaryDuring the Holocene, a layer of basic composition lava flows, identified as the Atotonilco Formation (Carrillo-Mart%u00ednez & Suter, 1982; Mora, 1998; Mart%u00ednez Flores & Ortega Gamboa, 2009), is situated beneath a polymict conglomerate with fragments of diverse composition known as the Pleistocene Daxi Formation (Simons & Mapes, 1956), which includes andesite rocks, limestone, shales and ashes of diverse composition. Alluvium is ultimately located in the floodplains of rivers and streams (Mora, 1998; Mart%u00ednez Flores & Ortega Gamboa, 2009), composed mainly of terrigenous deposits, gravel, and predominantly coarse material (Simons & Mapes, 1956).3.2. Mineralization eventsThe intrusion of Paleocene granitic-monzonitic rocks into carbonate formations (Mora, 1998), resulted in contact metamorphism and metasomatism (hydrothermal or pneumatolitic) (Simons & Mapes, 1956). Generally, skarn is formed in limeFigure 2. Topographic elevation map as Global Multi-Resolution Topography \and sampling sites. Physiography map (INEGI, 2001) with structural parameters from various sources. TMVB = Trans-Mexican Volcanic Belt, SMO = Sierra Madre Oriental. (Derived and modified from INEGI, 2002, 2010; Servicio Geol%u00f3gico Mexicano, 2002; Ramos Leal, 1996).o o o CD o, N N o o o co ~~ o o o o co N N o - Km Zimap%u00e1n 4 o o o co co N N o o o o co N N o o o .,., o, N N o o o \N N %u25a1 ll%u00bb%u00aemlrill Symblogy Physiography Physiographlc provinces 460000 - Ancient alluvial hills with ravines (TMVB) - Basalt hills (TMVB) High mountain range with convex slopes (SMO) Steep high mountain range (SMO) - Complex mountain range (TMVB) Sampling sites Limits of the lula River Basin Limits of the Moctezuma River Basin 462000 462000 o o o .,., o, N N o o o \N N '5( Mines 854 Fault (INEGI, 2002, 201 O) Fault (SGM, 2002) Normal Fault (Ramos Leal, 1996) Synclinal (Ramos Leal, 1996) Anticlinal (Ramos Leal, 1996) Dykes - Fault breccias (Ramos Leal, 1996) Topographic Elevation 3021 (m. a. s. l.)