Abstract The Caribbean Plate consists of a plateau basalt, formed probably in the Middle Cretaceous, complicated by a continental block, Chortís, several magmatic arcs, strike–slip motions along major fault systems such as the Motagua–Polochic fault zone in Guatemala, the pull-apart basin of the Cayman Trough and subduction zones below Central America and the Lesser Antilles. Five major collisional events have been identified: (i) Late Paleocene–Middle Eocene collision of the Greater Antilles with the Bahamas platform; (ii) Late Cretaceous collision of Chortís with the Maya Block; (iii) emplacement of nappes upon the Venezuelan foreland in the Cenozoic; (iv) collision of the Western Cordillera oceanic complex with the Central Cordillera of Colombia; and (v) Miocene collision of the eastern Costa Rica–Panama arc with the Western Cordillera. All these ‘orogenic events’ show an eastward movement of the Caribbean Plate relative to the Americas. Migration of the Jamaica Block from the Pacific caused obduction of the oldest ophiolites of Huehuetenango at the western end of the Polochic–Río Negro faults in Guatemala. South-southwest migration of the Chortís Block from west of Mexico and northward towards the Maya Block destroyed a trench associated with the Motagua–Jalomáx fault system and caused the Chuacús Orogeny, emplacing Guatemalan ophiolite complexes and metamorphosing the rocks from the Chuacús Series.

Divergence, expressed as the angle between the plate motion vector and the azimuth of a plate margin fault, has been proposed to explain development of contrasting styles of transtensional deformation along transform margins. We present the western North America–Caribbean plate margin as a test of this hypothesis. Here, geologic, earthquake, marine geophysical, and remote sensing data show two distinct structural styles: (1) east-west extension along north-trending rifts normal to the plate margin in the western study area (western Honduras and southern Guatemala); and (2) NNW-SSE transtension along rifts subparallel to the plate margin in the eastern study area (northern Honduras and offshore Honduran borderlands region). Orientations of rifts in each area coincide with the angle of divergence between the GPS-derived plate motion vector and the azimuth of the plate boundary fault, such that the western zone of east-west extension has an angle >10°, while the eastern zone of NNW-SSE extension occurs when the angle of divergence is between 5° and 10°. A narrow transition area in north-central Honduras separates the plate boundary–normal rifts of western Honduras from the plate boundary–parallel rifts to the east. Faults of the offshore Honduran borderlands extend onshore into the Nombre de Dios range and Aguan Valley of northern Honduras where tectonic geomorphology studies show pervasive oblique-slip faulting with active left-lateral river offsets and active uplift of stream reaches. Offshore, exploration seismic data tied to wells in the Honduran borderlands reveal active submarine faults bounding asymmetric half-grabens filled by middle Miocene clastic wedges with continued clastic deposition into Pliocene-Pleistocene. The north-trending rifts of western Honduras form discontinuous half-grabens that cut late Miocene ignimbrite strata. Plate reconstructions indicate the north-trending rifts of western Honduras developed in response to increased interplate divergence as the western margin of the Caribbean plate shifted from the Jocotan fault to the Polochic fault during the middle Miocene.

The Tacaná Volcanic Complex represents the northernmost active volcano of the Central American Volcanic Arc. The genesis of this volcanic chain is related to the subduction of the Cocos plate beneath the Caribbean plate. The Tacaná Volcanic Complex is influenced by an important tectonic structure as it lies south of the active left-lateral strike-slip Motozintla fault related to the Motagua-Polochic fault zone. The geological evolution of the Tacaná Volcanic Complex and surrounding areas is grouped into six major sequences dating from the Mesozoic to Recent. The oldest basement rocks are Mesozoic schists and gneisses of low-grade metamorphism. These rocks are intruded by Tertiary granites, granodiorites, and tonalites ranging in age from 12 to 39 Ma, apparently separated by a gap of 9 m.y. The first intrusive phase occurred during late Eocene to early Oligocene, and the second during early to middle Miocene. These rocks are overlain by deposits from the Calderas San Rafael (ca. 2 Ma), Chanjale (ca. 1 Ma), and Sibinal (unknown age), grouped under the name Chanjale–San Rafael Sequence, of late Pliocene–Pleistocene age. The activity of these calderas produced thick block-and-ash flows, ignimbrites, lavas, and debris flows. The Tacaná Volcanic Complex began its formation during the late Pleistocene, nested in the preexisting San Rafael Caldera. The Tacaná Volcanic Complex formed through the emplacement of four volcanic centers. The first, Chichuj volcano, was formed by andesitic lava flows and pyroclastic deposits, after which it was destroyed by the collapse of the edifice. The second, Tacaná volcano, formed through the emission of basaltic-andesite lava flows, as well as andesitic and dacitic domes that produced extensive block-and-ash flows ∼38,000, 28,000, and 16,000 yr B.P. The Plan de las Ardillas structure (the third volcanic center) consists of an andesitic dome with two lava flows emplaced on the high slope of the Tacaná ∼30,000 yr B.P. Finally, the San Antonio volcanic center was built through the emission of lava flows, andesitic and dacitic domes, and it was destroyed by a Peléan eruption at 1950 yr B.P. that produced a block-and-ash flow deposit. The Tacaná Volcanic Complex was emplaced along a NE-SW trend beginning with Chichuj, followed by Tacaná, Las Ardillas, and San Antonio. This direction is roughly the same as the NE-SW Tacaná graben (as proposed in this work), together with other faults and fractures exposed in the region. The rocks of the Chanjale-San Rafael Sequence and the Tacaná Volcanic Complex have a calc-alkaline signature with medium K contents, negative anomalies of Nb, Ti, and P, and enrichment in light rare earth elements, typical of subduction zones.

Abstract Precambrian and Palaeozoic basements are present in southern Mexico and Central America, where several crustal blocks are recognized by their different geological record, and juxtaposed along lateral faults. Pre-Mesozoic reconstructions must take into account the nature of such crustal blocks, their geological history, age and petrology. Some of those crustal blocks are currently located between southernmost north America (the Maya Block) and Central America (Chortís Block).To better understand the geology of these crustal blocks, and to establish comparisons between their geological history, we performed U–Pb dating of both igneous and metasedimentary key units cropping out in central and western Guatemala. In the Altos Cuchumatanes (Maya Block) granites yield both Permian (269±29 Ma) and Early Devonian (391±7.4 Ma) U–Pb ages. LA-ICPMS detrital zircon ages from rocks of the San Gabriel sequence, interpreted as the oldest metasedimentary unit of the Maya Block, and overlain by the Late Palaeozoic Upper Santa Rosa Group, yield Precambrian detrital zircons bracketed between c . 920 and c . 1000 Ma. The presence of these metasedimentary units, as well as Early Devonian to Silurian granites in the Mayan continental margin, from west (Altos Cuchumatanes), to east (Maya Mountains of Belize) indicates a more or less continuous belt of Lower Palaeozoic igneous activity, also suggesting that the continental margin of the Maya Block can be extended south of the Polochic fault, up to the Baja Verapaz shear zone. A metasedimentary sample belonging to the Chuacús Complex yielded detrital zircons with ages between c . 440 and c . 1325 Ma. The younger ages are similar to the igneous ages reported from the entire southern Maya continental margin, and show proximity of the Complex in the Middle-Late Palaeozoic. The S. Diego Phyllite, which overlies high-grade basement units of the Chortís Block, contains zircons that are Lower Cambrian ( c . 538 Ma), Mesoproterozoic ( c . 980 to c . 1150 Ma) and even Palaeoproterozoic ( c . 1820 Ma). Absence of younger igneous zircons in the San Diego Phyllite indicates that either its sedimentation took place in a close range of time, during the Late Cambrian, or absence of connection between Chortís and Maya Blocks during the Early–Mid-Palaeozoic. The Precambrian zircons could have come from southern Mexico (Oaxaca and Guichicovi Complexes), or from Mesoproterozoic Massifs exposed in Laurentia and Gondwana. Palaeogeographic models for Middle America are limited to post-Jurassic time. The data presented here shed light on Palaeozoic and, possibly, Precambrian relationships. They indicate that Maya and the Chortís did not interact directly until the Mesozoic or Cenozoic, as they approached their current position.