The Vale do Curaçá and Riacho do Pontal copper districts are located within the northern part of the Archaean São Francisco Craton and represent two pulses of mineralization. The copper districts have been identified as Iron-Oxide-Copper-Gold (IOCG) classes of deposits. An older metallogenic event associated with the Caraíba copper deposit, which is located in the Vale do Curaçá district, is related to Palaeoproterozoic (ca. 2 to 2.2 Ga) hydrothermal processes. A younger Neoproterozoic (ca. 750 to 570 Ma) episode of volcanism and associated plutonism is represented by the Riacho do Pontal mineral district. Seismic tomography data from across east-central Brazil show that the multiage Carajás province and Vale do Curaçá and Riacho do Pontal copper districts sit along either side of a prominent NW-trending upper lithospheric high-velocity zone. The edges of the high-velocity zone point to long-lived subparallel transcrustal structures that have been the focus of multiple reactivations and copper mineralization events. Regional gravity and magnetic maps show that the Vale do Curaçá copper district extends over an area greater than 110 km by 22 km. The magnetic and gravity values show significant variations correlated with this area. The district includes high gravity values associated with the Caraíba copper mine (>−35 mGal), which has a greater density (3.13 g/cm³) than the nonmineralized host rock density (2.98 g/cm³). The gravity anomaly signature over the Riacho do Pontal copper district is characterized by a 40-km long NW–SE trending Bouguer gravity low. The Ria4 occurrences of the Riacho do Pontal copper district are situated in these regional low-gravity domains. Data from regional airborne magnetic and ground gravity surveys were inverted to obtain a 3D magnetic susceptibility and density model, respectively, for the known districts. The results show that the Caraíba deposit is characterized by a both dense and magnetic source showing structural control by thrust shear zones. The 2D and 3D geological models show two main NNW prospective trends. Trends I and II have a sigmoidal shear shape and are positioned in the contact zone between domains with high magnetic susceptibility (SI > 0.005) and density > 0 g/cm³). Trend I is 40 km × 10 km in size and hosts the Caraíba, Surubim, and Vermelho copper mines and other minor deposits. The results obtained from the 3D magnetic inversion model for the region of the Riacho do Pontal district show weak magnetic anomaly highs extending along a NW–SE magnetic gradient trend. The gradient is related to mapped shear zones that overprint older and deeper NE–SW features of the São Francisco cratonic root. The area includes high gravity values associated with the Caraíba copper deposit, which has a greater density (3.13 g/cm³) than the nonmineralized host rock density (2.4 g/cm³).

中文翻译：

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在巴西绘制新的IOCG矿产系统图：库拉萨谷（Vale doCuraçá）和里亚托·杜邦塔（Riacho do Pontal）铜矿区

谷歌库拉（Vale doCuraçá）和里亚乔·杜邦塔（Riacho do Pontal）铜矿区位于古细菌圣弗朗西斯科·克拉顿（ArcheeanSãoFrancisco Craton）北部，代表着两个矿化脉动。铜矿区已被确定为氧化铁-铜-金（IOCG）类矿床。位于库尔萨河谷地区的卡拉伊巴铜矿床的一个较早的成矿事件与古元古代（约2至2.2 Ga）水热过程有关。Riacho do Pontal矿区代表了较年轻的新元古代（大约750至570 Ma）的火山活动和相关的岩屑作用。来自巴西中东部的地震层析成像数据表明，多生代的Carajás省以及Vale doCuraçá和Riacho do Pontal铜矿区位于西北偏北趋势较高的岩石圈高速区的两侧。高速带的边缘指向长寿命的次平行跨壳结构，这些结构一直是多次再活化和铜矿化事件的焦点。区域重力和磁图显示，库拉萨河谷铜矿区的范围超过110公里乘22公里。磁和重力值显示出与此区域相关的显着变化。该地区的重力值与卡拉巴铜矿（> -35 mGal）有关，密度比未矿化的主体岩石密度（2.98 g /cm³）高（3.13 g /cm³）。Riacho do Pontal铜区的重力异常特征是NW-SE长40公里，布格重力低。Riacho do Pontal铜矿区的Ria4矿床位于这些区域低重力域。分别反转了区域机载磁和地面重力调查的数据，分别获得了已知地区的3D磁化率和密度模型。结果表明，Caraíba矿床的特征是既有致密又有磁源，显示出受推力剪切带控制的构造。2D和3D地质模型显示了NNW的两个主要趋势。趋势I和II具有S形剪切形状，位于磁化率高（SI> 0.005）和密度> 0 g /cm³的磁畴之间的接触区。趋势I的规模为40公里×10公里，拥有Caraíba，Surumb和Vermelho铜矿和其他次要矿床。从Riacho do Pontal地区的3D磁反演模型获得的结果显示，弱磁异常高沿NW-SE磁梯度趋势延伸。该梯度与映射的剪切带有关，该剪切带覆盖了圣弗朗西斯科克拉通根的更老的NE-SW特征。该区域包括与卡拉巴铜矿床相关的高重力值，该密度比未矿化的主体岩石密度（2.4 g /cm³）大（3.13 g /cm³）。