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Puerto Rico geologic map units in Caguas quadrangle

Kabcj Formations A, B, C, and J(lower ?-upper ? Cretaceous)
Non-pillowed lava flows, volcanic breccia, sandstone, conglomerate, and minor limestone, siltstone, and tuff. Estimated thickness exceeds 5,000 m. Exposed in the Cayey, Patillas, Caguas, Comerio, and Yabucoa quadrangles
Kcag Granodiorite of Caguas Pluton(post middle Albian)
Granodiorite, foliate near contacts, autoclastic intrusion breccia present near margins; hornblende-rich autoliths(?) or xenoliths(?) are locally common. Exposed in the Caguas, Aguas Buenas, Juncos, and Gurabo quadrangles
Kdi Diorite(Campanian ? Albian ?)
Locally porphyritic, hornblende-rich diorite. Autoclastic intrusion breccia present near margins and locally in interior of stocks. Widely altered. Autoliths and/or xenoliths are widely present. Exposed in the Punta Guayanes, Patillas, Yabucoa, Coamo, and Caguas quadrangles
Kln Los Negros Formation(lower ?-upper ? Cretaceous)
Basaltic hyaloclastite-breccia, with stringers of pillowed basaltic lava, subordinate volcanic sandstone, and minor siltstone. Maximum estimated thickness, l,800 m. Exposed in the Ciales, Corozal, Naranjito, Aguas Buenas, Caguas, Gurabo, and Juncos quadrangles
Kper Perchas Formation(upper ?-lower ? Cretaceous)
Pillowed basaltic lava interbedded with basaltic tuff, volcanic sandstone, and minor hyaloclastite breccia. Lithologically the Perchas is indistinguishable from the Magueyes. Maximum estimated thickness, l,500 m. Exposed in the Ciales, Corozal, Aguas Buenas, Naranjito, Barranquitas, and Comerio quadrangles
Kr Robles Formation(Cenomanian-lower Albian)
Chiefly volcaniclastic sandstone and siltstone, subordinate lava and minor limestone, conglomerate and breccia; includes at the base, in the Cayey quadrangle, a calcarenite. Two pillowed basaltic andesite flows are enclosed in sandstone-siltstone sequence. Estimated thickness of the Robles exceeds 1,200 m. The Robles occurs in the Coamo, Juncos, Cayey, Caguas, Orocovis, and Comerio quadrangles. In the Barranquitas quadrangle rock lithologically and stratigraphically equivalent to the Robles is mapped as the Magueyes Formation.
Ksl Granodiorite-Quartz Diorite of San Lorenzo(post Cenomanian ?)
Massive hornblende-bearing granodiorite, grades into quartz diorite and locally into quartz monzonite. Autoliths(?) and xenoliths of metavolcanic rock are scattered throughout plutonic complex. Exposed in the Caguas, Juncos, Humacao, Patillas, Yabucoa, and Punta Guayanes quadrangles
Kslq Quartz Diorite Facies of Granodiorite of San Lorenzo(upper ? lower ? Cretaceous)
Quartz diorite, shows faint foliation near intrusive contacts, locally includes autoliths or xenoliths of quartz diorite and diorite. Grades into granodiorite but is largely quartz diorite. Exposed in the Caquas quadrangle
Kt Torrecilla Breccia(lower Albian)
Hyaloclastite breccia and associated lava flows, subordinate volcanic sandstone, conglomerate, and siltstone, minor limestone (Aguas Buenas Limestone). Maximum estimated thickness, 2,000 m. Mapped in part or in whole as Robles in central Puerto Rico. Exposed in the Barranquitas, Orocovis, Comerio, Aguas Buenas, and Cayey quadrangles
Qa Alluvium(Quaternary)
Ql Landslide Deposits(Holocene-Pleistocene ?)
TKha Hydrothermally altered rock(Tertiary ?-Cretaceous?)
Mixture of clay, sericite, albite, and pyrophyllite. Locally pyrite-bearing. Majority of areas mapped as hydrothermally altered are intrusive rocks. Exposed in the umacao, Juncos, Barranquitas, Cayey, Naranjito, Aquas Buenas, Comerio, Caquas, Cailes, Rosario, San German, Gurabo, Patillas, Naguabo, Guayama, and Punta Tuna quadrangles

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Page Last modified: 11:56 on 26-Mar-2012