Middle Miocene closure of the Central American Seaway

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Science  10 Apr 2015:
Vol. 348, Issue 6231, pp. 226-229
DOI: 10.1126/science.aaa2815
  • Fig. 1 Tectonic setting of the study area and location of samples.

    See Table 1. Thick lines represent major boundaries (28). Zero-milligal (0 mgal) contour (29) highlights the geodynamic continuity of the Panama arc; there are no structural breaks between the Uramita suture and the Canal Basin. (A and B) Detrital zircon ages recovered from (A) lower Miocene strata in the Canal Basin (6) and (B) Oligocene-Miocene strata in the Nuevo Mundo Syncline (18) and rivers draining the Eastern and Central cordilleras (19). (C) New U/Pb zircon ages for granitoids of the Panama arc; data point error ellipses are 68.3% confidence (see table S1).

  • Fig. 2 Detrital U/Pb zircon populations for all the samples recovered.

    (A) Middle Miocene strata; (B) Lower Miocene and Oligocene strata of the northern Andes. Data are binned insections of 10 million years (see tables S2 and S3). The youngest detrital zircon is labeled on top of the leftmost bin. See Table 1 and Fig. 1 for sample location.

  • Fig. 3 Paleogeographic reconstruction (28) of the Panama arc and northwestern South America during middle Miocene times (13 to 15 Ma).

    The first detrital loads from Panama arrived in one of two, or both, paths to the basins of northwestern South America: (i) along coastal currents transporting detritus product of the erosion of exposed plutonic rocks along the northern coast of the Panama arc and/or (ii) along fluvial channels draining emerging ranges parallel to the length of the Isthmus. The El Valle volcano, an edifice rising from sea level starting before 10 Ma (11), would only allow shallow and transient seaways between 15 and 10 Ma, as the Canal basin was connected to North America by a land bridge from Oligocene until middle Miocene times (30).

  • Table 1 Sample summary.

    See fig. S1 for stratigraphic location of samples.

    Detrital zircon
    sample name
    Sample typeAge
    U/Pb in detrital zircons from boreholes
    BH1SI-57969.4699–75.0015Cored boreholeMiddle Miocene
    SI-68169.4699–75.0015Cored boreholeOligocene–early Miocene
    BH2SI-66359.3651–74.4474Drill cuttingsOligocene–early Miocene
    BH3SI-59009.8907–74.6344Drill cuttingsMiddle Miocene
    BH4SI-68789.7160–75.1124Cored boreholeMiddle Miocene
    BH5SI-67038.6716–74.5976Cored boreholeOligocene–early Miocene
    BH6SI-66578.1702–75.4761Drill cuttingsMiddle Miocene
    SI-66728.1702–75.4761Drill cuttingsOligocene–early Miocene
    BH7SI-70458.5168–76.1256Cored boreholeMiddle Miocene
    BH8SI-68338.2680–76.2033Drill cuttingsOligocene–early Miocene
    U/Pb in detrital zircons from surface stratigraphic sections
    SMPSI-69978.5488–75.6922Hand sampleOligocene–early Miocene
    SA030337-26.4513–75.7403Hand sampleOligocene–early Miocene
    030337-66.4513–75.7403Hand sampleOligocene–early Miocene
    0303396.5414–75.7754Hand sampleOligocene–early Miocene
    0303576.4085–75.7241Hand sampleMiddle Miocene
    0303596.4166–75.7255Hand sampleMiddle Miocene
    0303626.5064–75.8194Hand sampleOligocene–early Miocene
    U/Pb in magmatic zircons from granitoid surface samples
    DV-1655.7680–76.2490Hand sample43.8 ± 0.8 Ma
    DV-1675.7709–76.2475Hand sample42.5 ± 1.3 Ma
    GA-0018.5094–77.3371Hand sample49.5 ± 0.9 Ma
    VM-0018.4993–77.3221Hand sample49.7 ± 1.6 Ma
    VM-0038.4847–77.3402Hand sample49.5 ± 1.1 Ma
    SI-8608.8370–77.6218Hand sample59.0 ± 1.9 Ma
    SI-9008.6638–77.4321Hand sample58.6 ± 1.6 Ma
    SI-10929.2985–78.1047Hand sample58.3 ± 1.0 Ma

Supplementary Materials

  • Middle Miocene closure of the Central American Seaway

    C. Montes, A. Cardona, C. Jaramillo, A. Pardo, J. C. Silva, V. Valencia, C. Ayala, L. C. Pérez-Angel, L. A. Rodriguez-Parra, V. Ramirez, H. Niño

    Materials/Methods, Supplementary Text, Tables, Figures, and/or References

    Download Supplement
    • Materials and Methods
    • Supplementary Text
    • Figs. S1 to S3
    • References
    Tables S1 to S5
    Table S1. Magmatic U/Pb data
    Table S2. Detrital U/Pb data for lower Miocene strata.
    Table S3. Detrital U/Pb data for lower Miocene and Oligocene strata.
    Table S4. Heavy mineral data
    Table S5. Petrographic data

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